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5082858/NANR201 V6 Publication.docx

Defra NANR 201 – Environmental Noise

Valuation – The Costs and Benefits of Remediation Measures

Final Report

August 2011

Notice

This report was produced by Atkins Limited for Defra for the specific purpose of Contract NANR201.

This report may not be used by any person other than Defra without Defra's express permission. In any event, Atkins accepts no liability for any costs, liabilities or losses arising as a result of the use of or reliance upon the contents of this report by any person other than Defra.

Document History

JOB NUMBER: 5082858 DOCUMENT REF: 5082858/2009/August/11

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NANR 201 – The Costs and Benefits of Remediation Measures

5082858/NANR201 V6 Publication.docx 1

Foreword It can be seen that the work undertaken for this study was completed in 2011 with the majority of the work being undertaken in 2008 and 2009. As a result of resourcing and prioritisation issues, it has not proved possible to complete until now the work necessary to publish this report. Consequently, although the principles described in this report are still valid, there are some details in the report that reflect when the drafting occurred and which have now been superseded. In general, these include issues such as:

• References to guidance;

• References to noise management policy;

• References to other research;

• The prices quoted;

• The second round of strategic noise mapping. It is important to bear this point in mind when reading the report.



Contents

Section Page

Executive Summary 7

Glossary of Terms 8

1. Introduction 11

Noise Control Measures and Valuation 11

Assessment Approach 11

2. Project Methodology 12

Project Context 12

Identification of Noise Control Measures 12

Costs of Noise Control Measures 12

Valuation and Analysis Methodologies 13

Stakeholder Consultation 13

Determining an Appropriate Approach to Assessment 13

Case Studies 14

Reporting 14

Chapter Summary 14

3. Policy and Initiatives 15

European Union 15

United Kingdom 16

Chapter Summary 19

4. Adopting a Consistent Approach 20

Acoustic Definitions 20

Assessment Input Parameters 23

Noise Impact Types 24

Noise Sensitive Receptors 27

Sensitivity and Significance 29

Chapter Summary 30

5. The Assessment Process 31

Design Targets 31

Assessment Years 32

Scoping 32

Scenarios 34

Do-Minimum Scenario 34

Noise Control Scenarios 35

Study Area 35

Calculations 36

Presentation of Results for Assessment 37

Costs of Noise Control Measures 39

Value of Noise Changes 39

Non-acoustic Assessments 39

Cost Benefit Analysis 39



Reporting 40

Chapter Summary 40

6. Methods of Controlling Noise 41

Rail Grinding and Wheel Turning 41

Rail Pads 42

Alternative Road Surfaces 42

Altering Traffic Flow and Imposing Vehicle Restrictions 42

Speed Restrictions 42

Noise Barriers 42

Noise Insulation of Properties 43

Chapter Summary 44

7. Costs of Noise Control Measures 45

Cost of Screening Noise Control Measures 45

Cost of Noise Control Measures for Road Traffic Noise 46

Cost of Noise Control Measures for Rail Traffic Noise 56

Costs of Building Envelope Improvements 60

Chapter Summary 60

8. Valuing Changes in Noise 61

Noise Annoyance at Residential Dwellings 61

Valuation of Changes in Internal Levels 62

Other Noise-Sensitive Receptors 62

Health Effects 62

Annoyance versus Health Effects 64

Approaches in the UK 64

Practical Considerations 66

Valuation and Discounting Example 67

Chapter Summary 72

9. Other Costs and Benefits 73

Costs Associated With Noise Control Measures 73

Costing Methods in the UK 75

Transport Assessment 76

Sustainability Management 77

Environmental Aspects 80

Planning and Building Control 82

Chapter Summary 85

10. Framework for Cost Benefit Analysis 86

Options Appraisal in UK Central Government 86

The Appraisal Process 87

Practical Issues 89

Chapter Summary 90

11. Toolkit 91

Tool1: Identify Constraints and Opportunities 91

Tool2: Scoping of Potential Noise Control Measures 93

Tool3: Scoping of Non-Acoustic Considerations 94

Tool4: Definition of Scenarios 95



Tool5: Method of Calculation 96

Tool6: Calculation Points 97

Tool7: Internal Noise Levels 97

Tool8: Assessment of Acoustic Benefits 98

Tool9: Assessment of Non-Acoustic Costs and Benefits 98

Tool10: Collation of Assessment Data 99

Tool11: Cost Benefit Analysis 100

Tool12: Reporting 100

Chapter Summary 100

12. Toolkit Example 101

Tool1: Identify Constraints and Opportunities 101

Tool2: Scoping of Potential Noise Control Measures 102

Tool3: Scoping of Non-Acoustic Considerations 102

Tool4: Definition of Scenarios 102

Tool5: Method of Calculation 102

Tool6: Calculation Points 102

Tool7: Internal Noise Levels 102

Tool8: Assessment of Acoustic Benefits 102

Tool9: Assessment of Non-Acoustic Costs and Benefits 105

Tool10: Collation of Assessment Data 107

Chapter Summary 108

13. Case Studies 109

Case Study Analyses 109

Selection of Case Studies 109

Noise Control Options Tested 111

Review of Case Study Results 112

Traffic Management Case Study 126

Summary of Case Study Analyses 133

Sensitivity Testing 134

Chapter Summary 136

14. Conclusions 137

Noise Control Measures 137

Valuation 137

Assessment Approach 137

Further work 138

15. References 139

Appendices

Appendix A - Further Initiatives Relevant to Action Plans 143

A.1 Introduction 144

A.2 Strategic Noise Mapping 144

A.3 UK National Ambient Noise Strategy 145

A.4 Mayor of London’s Ambient Noise Strategy 146

A.5 Traffic Noise Action Programme (TNAP) 147

A.6 London Boroughs 147



A.7 Regional Noise Strategies and Initiatives 147

A.8 Highways Agency Hotspots Noise Assessments 148

Appendix B - Noise Control Measures 151

B.1 Introduction 152

B.2 Noise Remediation Measures 154

B.3 Quiet Vehicles – Power Train and Tyre Noise 155

B.4 Low Noise Heavy Goods Vehicles 157

B.5 Road surfaces 159

B.6 Railway and Train Maintenance 161

B.7 Rolling Stock Design 163

B.8 Streetworks and street maintenance 165

B.9 Altering Traffic Flow and Imposing Vehicle Restrictions 167

B.10 Traffic Calming and Speed Limits 169

B.11 Smooth Driving 172

B.12 Noise barriers 174

B.13 Vegetation 176

B.14 Land Use Planning and Management 177

B.15 Building Design 178

B.16 Economic and Social Regulating Methods 179

Appendix C - Valuation Methods 181

C.1 Introduction 182

C.2 Environmental Valuation Methods 182

C.3 Noise Valuation Methods 182

C.4 TAG Valuation Guidance 184

Appendix D - Methods of Appraisal 188

D.1 Introduction 189

D.2 Cost-Benefit Analysis (CBA) 189

D.3 Cost-Effectiveness Analysis (CEA) 189

D.4 Multi-Criteria Analysis (MCA) 190

D.5 Quantitative Measurement (QM) 190

D.6 Qualitative Assessment (QA) 190

Appendix E - Case Study Results 192

E.1 Case Study 1 193





E.6 Case Study 6a 207

E.7 Case Study 6b 210












Appendix F - Review of Sound Insulation Performance of Windows 252

F.1 Introduction 253

F.2 PPG24 1994 – Annex 6 253

F.3 BB93 – Section 3.4 253

F.4 BB101 – Section 4.3.1 253

F.5 BS8233: 1999 – Section 8.4.7 254

F.6 BS8233: 1999 – Section 6.7.1 254

F.7 BRE Information Paper IP 6/94 – The sound Insulation Provided by Windows 254

F.8 BRE Digest 338 255

F.9 BRE Digest 379 255

F.10 BS6262 – Glazing for Buildings, Part 2 – Code of Practice for Energy, Light and Sound (2005) 256

F.11 BRE Domestic Energy Fact File (2006) 256

F.12 BRE Report 162 – Background Ventilation of Dwellings: a Review (1989) 257

F.13 Summary of Glazing Performance 258

Appendix G Planning Legislation 262

G.1 Introduction 263

G.2 Planning Legislation and Process 263



Executive Summary

This report details the results of project NANR 201 Environmental Noise Valuation - the Costs and Benefits of Remediation Measures undertaken by Atkins for Defra. The objective of the project is to provide practical advice for assessing the costs and benefits of noise control projects, primarily for road traffic and railway noise sources. The project has been undertaken in consultation with stakeholders.

This project has reviewed methods for assessing the costs of noise control measures for road traffic noise and railway noise and valuing the resulting acoustic benefits. An assessment approach has been defined which allows such noise control measures to be assessed and compared in a consistent way.

At the time of writing, in the UK, Noise Action Plans are being prepared as required by the EC directive on environmental noise, referred to as the Environmental Noise Directive. The action plans identify important areas, and it is necessary to investigate options for managing noise in these areas. The results of this project are intended to assist in determining appropriate noise control measures in those areas of high noise levels, referred to in this report as Noise Management Areas.

Noise Control Measures

In order to predict, assess and compare costs and changes in noise, appropriate methodologies have been developed to consider the following noise control measures:

• Noise barriers;

• Quieter road surfacing;

• Rail maintenance measures;

• Traffic management options;

• Building improvement measures.

The prediction methods are generally based on the nationally approved calculation methodologies Calculation of Road Traffic Noise and Calculation of Railway noise, although the advice given could equally be applied to any other calculation methodology. A review of the potential costs of these noise control options considered has been undertaken.

Valuation

The Department for Transport’s Transport Analysis Guidance method for valuing the changes in noise at residential properties has been used to monetise the benefits arising from external noise control measures. Further research is required to value benefits from building envelope measures.

Assessment Approach

A step by step approach to assessing noise control measures provides scoping tools to allow inappropriate measures to be excluded from further consideration at an early assessment stage, In addition, other types of assessment which may be required have been identified which may further limit the types of measure being considered.

The advice in this report provides a method for an economic comparison between the acoustic benefits provided by, and the installation costs of, the noise control measures considered in the report.

The report provides information on the minimum level of detail required for an assessment. Sensitivity tests identify a minimum change in noise which must be considered, and a threshold below which noise levels can be excluded. The analysis shows that it is important that all receptors meeting these criteria are considered, particularly those at the higher noise levels which may influence the valuation. Selection of an appropriate study area is critical in ensuring accurate quantification of acoustic benefits.



Glossary of Terms

Note, all acoustic terms are defined in Chapter 4 of this report.

Term Meaning / Definition

absorptive An absorptive finish to a noise barrier reduces reflections

AONB Area of Outstanding Natural Beauty

AST Appraisal Summary Table

ATC Automatic Traffic Count

AWS Automatic Warning System

ballast Layer of crushed rock or gravel upon which railway track is laid

BCR Benefit Cost Ratio

bogie Chassis or framework carrying wheels, attached to a rail vehicle

BSi British Standards Institution

Building Control Body Local authority or approved inspectors building control service

building envelope The outer shell of a building which separates the interior and the exterior environments

CBA Cost Benefit Analysis

CCTV Closed Circuit Television

CEA Cost Effectiveness Analysis

CERTASS Certification and self assessment

cess The area alongside a rail track, at a lower level than the sleeper bottom, in order to provide drainage.

COBA Cost Benefit Analysis (software)

CRN Calculation of Railway Noise 1995, Amended 1996

CRTN Calculation of Road Traffic Noise 1988

cut and cover Method of construction for shallow tunnels where a trench is excavated and roofed over

DALY Disability Adjusted Live Year

Defra Department for Environment, Food and Rural Affairs

DfT Department for Transport

DMRB Design Manual for Roads and Bridges

EC European Commission

EIA Environmental Impact Assessment

END Environmental Noise Directive

ERTMS European Railway Traffic Management System




EU European Union

Externalities An impact that is not directly involved in the transaction

FENSA Fenestration Self Assessment Scheme

GDHI Gross Disposable Household Income

GDP Gross Domestic Product

GDPO General Development Procedure Order

Hansard The edited verbatim report of proceedings in both UK Houses of Parliament

hedonic A hedonic model is one where the independent variables are related to quality; e.g. the quality of a product that one might buy or the quality of a job one might take.

HGV Heavy Goods Vehicle

HMT Her Majesty’s Treasury

hot rolled asphalt (HRA) Coarse aggregate surrounded by a mixture or mastic of bitumen, sand and very fine material called filler. Predominant surfacing material for UK main roads until about 1995.

Infrastructure The basic physical and organisational structures needed for the operation of a society or enterprise, or the services and facilities necessary for an economy to function.

LPA Local Planning Authority

MCA Multi-Criteria Analysis

MOT Ministry of Transport (test for motor vehicles)

MOVA Microprocessor Optimised Vehicle Actuation

NPV Net Present Value

PCU Passenger Car Unit, The basic unit of traffic flow used in traffic modelling equal to the equivalent of a typical car.

PPG Planning Policy Guidance

PPS Planning Policy Statement

PV Present Value - PVB for benefits and PVC for costs

QA Quantitative Assessment

QM Quantitative Measure

QUADRO Queues and Delays at Roadworks (software)

rail pad Resilient pad directly beneath the rail at each sleeper.

reflective A reflective finish to a noise barrier does not reduce reflections

SCOOT Split Cycle Offset Optimisation Technique

SMS Sustainability Management System

stone mastic asphalt Manufactured from hard rock aggregates with particle sizes selected to leave




(SMA) space for a bitumen and limestone powder mixture known as ‘mastic’.

TA Transport Assessment

TAG Transport Analysis Guidance

tinnitus Perception of sound within the human ear in the absence of corresponding external sound.

TOC Train Operating Company

TPWS Train Protection and Warning System

TUBA Transport Users Benefit Appraisal (software)

TWA Transport and Works Act

valuation Estimation of the potential market value of a financial asset or liability

VOC Vehicle Operating Costs

WebTAG www.webtag.org.uk hosted the TAG guidance until the DfT incorporated this guidance within its website at www.dft.gov.uk/webtag

WG AEN EU Working Group on the Assessment of Environmental Noise

WHO World Health Organisation

WTP Willingness To Pay



1. Introduction

1.1 This report details the results of project NANR 201 Environmental Noise Valuation - the Costs and Benefits of Remediation Measures undertaken by Atkins for Defra. The objective of the project is to provide practical advice for assessing the costs and benefits of noise control projects, primarily for road traffic and railway noise sources.

1.2 The project has been undertaken in two phases, and in consultation with stakeholders. The first project phase has reviewed research and outcomes from literature and other projects to identify:

• methods of noise control, including the identification of costs; and

• approaches for valuing the resulting changes in noise levels.

1.3 The second project phase defines an assessment approach and develops a toolkit approach for this type of project, and tests these using case studies.

1.4 At the time of writing, in the UK, Noise Action Plans are being prepared as required by the EC directive on environmental noise, referred to as the Environmental Noise Directive. The action plans identify important areas, and it is necessary to investigate options for managing noise in these areas. The results of this project are intended to assist in determining appropriate noise control measures in those areas of high noise levels, referred to in this report as Noise Management Areas.

Noise Control Measures and Valuation

1.5 For each method of noise control, appropriate methods of calculating noise levels have been identified, allowing noise impacts to be assessed using nationally approved calculation methodologies. In addition, costs for each measure have been identified along with other types of assessment which are likely to be required. The primary measures considered in this report are:

• Noise barriers;



• Traffic management options.

1.6 A review of methods of valuing noise impacts has been undertaken to identify those methods that would apply for this type of project. Each of the different noise control measures has also been reviewed to determine any other types of assessment that may be required.

Assessment Approach

1.7 Each step in the process for assessing the costs and benefits of noise control measures has been examined, tested and described. The report presents a descriptive assessment approach and a toolkit of appropriate tools. Worked examples are presented illustrating the necessary level of information required to consider:

• The benefits associated with reduced noise levels arising from a noise control measure.

• The costs associated with installing the noise control measure.

1.8 Where possible, the approach draws on existing methods of assessment and valuation.

1.9 A series of case studies have been examined, based on previous projects, to test and explore data requirements, study area sizes, and the effects of limiting the scope of the assessment.



2. Project Methodology

2.1 This project (reference ‘NANR 201 – Environmental Noise Valuation, The Costs and Benefits of Remediation Measures’) requires an assessment of the practicalities of undertaking Cost Benefit Analysis for noise control projects by reference to existing research and by investigation of case studies in the UK.

2.2 The project aims to provide practical advice for assessing the costs and benefits of noise control projects primarily in the road and rail sectors and to establish if simple approaches could be adopted for scoping studies. Atkins work on this project was undertaken in two main phases. The first phase of the project:

• Set the project work in the context of relevant policy and plans;

• Identified potential types of noise control measures and noise prediction methods;

• Reviewed the literature and other sources of information to obtain costs;

• Reviewed the literature for appropriate valuation and analysis methodologies;

• Consulted with stakeholders.

2.3 Work from the first phase of the project was reported in a series of working papers which have been incorporated into different sections of this report.

2.4 The second phase of the project:

• Developed an assessment methodology for considering noise control measures;

• Tested the assessment methodology using case studies;

• Presented the results of the project in this report.

Project Context

2.5 A review was undertaken of the legislation that requires strategic noise maps and action plans to be produced. The action plans available at the time of writing, including draft versions, have been reviewed to establish broad types of potential noise control measures and any thresholds for noise management areas. A review was also undertaken of other relevant plans and policies.

2.6 This review is presented in Chapter 3 of this report.

Identification of Noise Control Measures

2.7 A review of noise control measures was undertaken, including the types of potential noise control measures identified in the Noise Action Plans. The review identified the potential scope, extent and timescale for benefits from each type of measure and identified methods of calculation to predict potential changes in noise.

2.8 The review of control measures is presented in Chapter 6 of this report with further details provided in Appendix B.

Costs of Noise Control Measures

2.9 Where the literature review provided indicative costs for different types of measures, these were collated. The costs were also reviewed by Atkins’ highways and railways engineers who provided additional costs for certain types of measures, and identified the standard method for estimating other costs associated with the construction of noise control measures.

2.10 The review of costs is presented in Chapter 7 of this report.



Valuation and Analysis Methodologies

2.11 Initially, the approaches to cost benefit analyses were reviewed in line with Government guidance in order to inform the outcomes of the project.

2.12 A literature review was undertaken in conjunction with Atkins’ economists of different dose- response relationships and methods of valuing noise impacts to determine the most appropriate methods for this project.

2.13 The review of valuation methods is presented in Chapter 8 of this report, with further information in Appendix C.

Stakeholder Consultation

2.14 Discussions were held with stakeholders within England (Defra), Scotland (Scottish Executive) and Wales (Welsh Assembly Government) to identify potential key issues which are expected in the implementation of the action planning. The result of these discussions was that envisaged noise control measures are broadly grouped as:

• Traffic management measures;

• Road surface measures or track/rolling stock measures;

• Roadside/trackside measures;

• Improvement of the building envelope.

2.15 The discussions identified that the overall method for the identification of appropriate noise control measures was not clearly defined, and that the focus of the project should be based on the more traditional type of noise control measures, found commonly around the UK, rather than to provide higher level advice for more strategic types of noise control measures such as economic and social regulation and alternative transport modes.

2.16 The main requirement is for the project advice to allow costs and benefits of noise control measure to be assessed, defining a process which sets out:

• How to define the ‘study area’;

• What comparisons to make;

• Consideration of internal and external areas;

• How to assess the change in noise levels;

• How to value any changes in noise;

• How to identify the costs of measures;

• Identification of likely non-acoustic costs and benefits;

• How implementation of the measure might affect the strategic noise maps.

Determining an Appropriate Approach to Assessment

2.17 The information gathered for the first phase of the project was reviewed, and an approach for the assessment of the cost effectiveness of noise control measures was developed, drawing where possible on existing methods of assessment and appraisal.

2.18 Atkins’ range of environmental, planning, building control and sustainability specialists were consulted to provide advice on any likely non-acoustic assessments that may be required when measures are being considered.



2.19 The identified assessment approach is described in Chapter 5 of this report, and non-acoustic considerations are described in Chapter 9 of this report. The advice is presented as a series of tools in Chapter 11, with a worked example in Chapter 12.

Case Studies

2.20 In order to inform the process, a number of case studies have been selected to demonstrate the assessment approach, to establish if high level advice can be determined, and to inform potential constraints. The case studies consider a range of noise barriers, quieter road surfacing and traffic management options.

2.21 The case studies selected are all based on Atkins’ noise maps for previously completed projects, and the results are presented in Chapter 13 of this report.

Reporting

2.22 The working papers from the first phase of the report have been incorporated into this report with comments from reviewers taken on board, and sections have been included describing the work undertaken in the second phase of the project.

Chapter Summary

2.23 This chapter has outlined the basic methodology and approach for the work undertaken to complete this project.



3. Policy and Initiatives

3.1 Strategic noise maps and action plans are required under European policy on environmental noise (Environmental Noise Directive). The results of this study are expected to help inform the decision making process for noise control measures to address areas identified by the action planning process. This chapter sets out the relevant policy.

European Union

The Environmental Noise Directive (END)

3.2 Further to the publication of Green Paper in 19961, the European Commission issued the Directive 2002/49/EC relating to the Assessment and Management of Environmental Noise in 20022. This directive is commonly referred to as the Environmental Noise Directive or END and has three main objectives:

• Defining the noise environment; by requiring competent authorities in Member States to draw up "strategic noise maps";

• Informing and consulting the public about noise exposure, its effects, and the measures considered to address noise; and

• Addressing local noise issues by requiring competent authorities to draw up “Action Plans” to manage and, where necessary, reduce noise and maintain environmental noise quality where it is good.

3.3 The first round of the END process is presently being implemented in all EU Member States. It covers transportation and industrial noise in the environment. Strategic noise maps and action plans are to be updated in second and subsequent rounds at five year intervals.

3.4 The directive requires that noise maps and Action Plans on noise be made for:

• Agglomerations with populations greater than 100,000;

• Major roads with more than 3,000,000 vehicles a year, approximately 8,000 a day;

• Major railways with more than 30,000 trains a year;

• Major civil airports with more than 50,000 operations year (approximately 135 day), excluding training on light aircraft.

3.5 The strategic noise maps and action plans in the first round of the END process are required for; agglomerations with populations greater than 250,000, major roads with flows greater than 6,000,000 a year, major railways with flows greater than 60,000 trains a year. All major airports are identified in the first round.

3.6 The END requirements for Strategic Noise Mapping and Action Planning are summarised below.

Strategic Noise Mapping

3.7 The END gives details of strategic noise mapping requirements for road, rail, air and industrial sources. These requirements include calculation methods to be used, calculation heights, noise indices and reporting arrangements.

3.8 The European Commission published a Good Practice Guide3 on noise mapping and has initiated a number of projects on potential harmonised calculation methods for future use. Further details are included in Appendix A.



Action Planning

3.9 The END requires that Action Plans apply in particular to the most important areas as established by strategic noise maps.

3.10 The measures specified in the Action Plans should address important areas which may be identified by a margin with which a relevant limit value is exceeded or other criteria as chosen by each member state.

3.11 There are several minimum requirements of what is to be included in an Action Plan, one of which is, ‘financial information (if available): budgets, cost-effectiveness assessments, cost-benefit assessment’.

3.12 Actions highlighted in the END which the competent authority may want to take include:

• Traffic planning;

• Land-use planning;

• Technical measures at noise sources;

• Selection of quieter sources;

• Reduction of sound transmission;

• Regulatory or economic measures or incentives.

3.13 The Action Plans should also include an estimate of the number of people who would benefit from the measure, whether that is in terms of reduced sleep disturbance, reduced annoyance or some other measure.

3.14 The plans should describe the identification and noise level management of existing quiet areas within agglomerations.

3.15 An important requirement of the END is that the public are consulted about proposals for Action Plans giving fair time and opportunity to participate in the preparation and review of the Action Plans. Neighbouring member states are required to co-operate on the Action Plans for border regions.

United Kingdom

UK Environmental Noise Regulations

3.16 In the UK, the Environmental Noise Directive has been implemented into national legislation as follows:

• The Environmental Noise (England) Regulations 20064 (as amended5).

• The Environmental Noise (Wales) Regulations 20066

• The Environmental Noise (Scotland) Regulations 20067

• The Environmental Noise Regulations (Northern Ireland) 20068.

3.17 Each of these regulations transposes the requirements of the END, and defines who is responsible for producing the strategic noise maps and action plans.

3.18 Noise Maps and Action Plans are to be drawn up by a range of authorities depending on the noise source:

• In all cases, the responsibility for drawing up strategic noise maps and action plans for airports lies with the airport operators;

• In England, all other strategic noise maps and actions plans must be drawn up by the Secretary of State;



• In Scotland all other strategic noise maps and action plans must be drawn up by the Scottish Ministers;

• In Wales all other strategic noise maps and action plans must be drawn up by the Welsh Assembly;

• In Northern Ireland strategic noise maps and action plans must be drawn up by the Department for the Environment (industry and consolidated plans), the Department for Regional Development (roads) and Northern Ireland Transport Holding Company (railways).

3.19 The government intends that in England Action Plans will assist the management of environmental noise in the context of sustainable development.

Action Planning Thresholds

3.20 The Noise Action Plans apply to the most important areas, as identified by the strategic noise maps. It is the responsibility of the competent authority to determine which areas are those that are most important. Criteria have been set for determining these areas, which are described below. In this report, such areas are referred to as Noise Management Areas.

3.21 A noise action plan sets out a procedure designed to manage the effects of noise from road traffic, rail traffic, air traffic and from sites of industrial activity and to reduce it if necessary. Such a reduction would aim to avoid, prevent or reduce harmful effects of noise exposure on people.

3.22 Actions plans are required in connection with major roads, major railways, major airports and agglomerations. The competent authorities for preparing these Action Plans are defined above

Identification of Noise Management Areas

3.23 The analysis of the strategic noise maps will identify areas which meet the criteria described in Table 3.1. The result is a number of discrete locations (Important Areas) to be investigated to determine what further measures, if any, might be implemented to assist the management of environmental noise.

3.24 Any actions considered should be set in the context of any existing policy measures and the principles set out in current legislation and guidance.

Consideration of Noise Control Measures

3.25 The work for this project concentrates on the identification of potential measures where there is scope for implementing additional noise management measures.

3.26 The work is based around determining an approach to allow a selection of noise control measures within one noise management area, and providing a method for comparing costs and benefits, and allowing different design options to be considered.

3.27 The approach identified could be used to compare overall results between different noise management areas, and inform a prioritisation of measures across multiple noise management areas.

Implementation

3.28 Once the Important Areas have been investigated, it is expected, for England, that there are four possible outcomes, as described in the draft Noise Action Plans for England9,10,11,12, 13,14, and repeated below.

a) “It is possible to be able to implement an action and there are financial resources immediately available to do so;

b) It is possible to be able to implement an action but there are no immediately available financial resources to do so;



c) It is not possible to implement any action because there is no scope for doing so (e.g. reasonable sound insulation already exists at the affected dwelling, or a noise barrier at its optimum size and location already exists), or there is some overriding technical issue that prevents implementation (e.g. ground conditions do not allow a barrier to be erected); or

d) It is not possible to implement any action because there would be large adverse non- acoustics effects that could not be accommodated by the proposed measure. Such non acoustic effects could include an adverse effect on safety, or a significant adverse air pollution impact, or an unacceptable increase in congestion or journey times.”

3.29 The noise action plans for Scotland15,16,17 Wales18,19,20,21 and Northern Ireland22 also discuss this issue, but do not define these outcomes explicitly.

3.30 The work on this project is intended to provide information on costs and potential non-acoustic effects. However issues related to the availability of financial resources are beyond the scope of this project.

Important Area Thresholds

3.31 Each country within the United Kingdom has specified thresholds to determine the most important areas from the first round of strategic noise mapping. In some situations the thresholds are draft, and they may be adjusted on confirmation or in subsequent rounds of strategic noise mapping and action planning. The current thresholds are set out in the following table.

Table 3.1 – Thresholds for Important Areas

Road Traffic Noise Railway Noise Aircraft Noise

Industrial Noise

England 1% of population affected by the highest noise levels.

First priority locations are those where the LA10,18hr at those locations is at least 76dB according to the results of the strategic noise mapping.

No investigation required if the level does not exceed 65dB according to the strategic noise mapping.

1% of population affected by the highest noise levels.

First priority locations are those where the LAeq,18hr at those locations is at least 73dB according to the results of the strategic noise mapping.

No investigation required if the level does not exceed 65dB according to the strategic noise mapping.

Each airport dealt with specifically

No limit criteria specified.

No specific new measures proposed

Scotland 1% of population affected by the highest noise levels

1% of population affected by the highest noise levels

Each airport dealt with specifically

No limit criteria specified

Wales 1% of population affected by the highest noise levels where the LA10,18hr at those locations is at least 68dB

1% of population affected by the highest noise levels where the LAeq,18hr at those locations is at least 68dB

N/A No limit criteria specified

Northern Ireland

To be defined To be defined Each airport dealt with specifically

To be defined

Potential Actions

3.32 The initial action plans defined a range of approaches that already occur to control noise:



• Control of noise at source;

• Planning controls;

• Compensation and insulation;

• Maintenance;

• General policy;

• Specific initiatives;

• Limit values.

3.33 Some of the actions which the competent authorities intend to take in the next five years following the adoption of the plan are: to liaise with the relevant authorities to identify the important areas for potential action, and to liaise with relevant local authorities to participate in the identification of any measures in these areas.

3.34 Possible actions in important areas for the control of road and railways noise are (in no particular order) to:

• Improve the sound insulation of building receptors;

• Erect noise barriers;

• Implement HGV and night-time bans;

• Use low noise road surfaces;

• Implement local traffic management measures;

• Use traffic management and redirection;

• Implement speed reductions;

• Increase the frequency and nature of railhead grinding;

• Alter the type of rolling stock that uses the particular rail corridor.

Chapter Summary

3.35 This chapter has described the requirements of the EC Environmental Noise Directive, and how those have been implemented in the United Kingdom. The thresholds for determining important noise management areas have been defined, and set with potential noise control measures.



4. Adopting a Consistent Approach

4.1 This chapter of the report sets out relevant background information to acoustic terminology, criteria for significance, calculation input parameters and sensitive receptors. The information contained here should be referred to for the cross-comparison of options in different locations, on a consistent basis. There are five sections to this chapter:

• Definitions of acoustic terminology to allow results to be interpreted consistently;

• Assessment of input parameters to allow calculations to be undertaken consistently;

• Guidance on main types of impacts due to noise;

• Guidance on the selection of noise sensitive locations;

• Guidance on significance and sensitivity.

Acoustic Definitions

4.2 The decibel, or dB, is the unit of measurement used for sound pressure levels. The scale is logarithmic rather than linear. The threshold of hearing is 0dB and the threshold of pain is 120dB. In practical terms these limits are seldom experienced and typical levels lie within the range 30dB (a quiet night time level in a bedroom) to 90dB (at the kerbside of a busy city street).

4.3 The sound pressure level is a measure of the acoustic energy at one point. If a sound is 3dB higher (or lower) than another sound, then it contains twice (or half) the amount of acoustic energy. Subjectively, if a sound is judged to be twice as loud (or quiet) as another sound, then its sound pressure level would be 10dB higher (or lower). Sound pressure levels are denoted with the symbol “L”

4.4 Under controlled conditions, the human ear is just able to detect a change in sound level of 1dB. Changes in sound levels less than 1dB are not detectable by humans. For sounds in everyday life, it is usually accepted that an individual will notice a change in sound pressure level of 3dB.

Sound vs. noise

4.5 Sounds made by everyday sources including transportation, businesses and industry, and those in a residential context are commonly grouped together under the heading “Community Noise”23, and the use of the word noise is typically used to refer to “unwanted” sounds. Therefore, sound levels generated from vehicles on roads are often referred to as road traffic noise, with the same applying to railways, aircraft and industrial sources. The sound levels from these particular sources are considered together as “Environmental Noise”. Throughout this report, the term “noise levels” is used to describe sounds generated by these sources.

The variability of sounds

4.6 Sounds can vary in their frequency content – i.e. the relative contributions of high-pitched and low-pitched components, and they can vary with time – i.e. the different high-pitched and low- pitched components can become louder or quieter over time.

4.7 There are two main simplifications one can make to describe a sound signal, firstly, it is possible to sum together the high-pitched and low-pitched components so that the entire frequency content is represented by a single number, and secondly it is possible to describe the time variability of a signal by a number of parameters, including the maximum and average level.

Frequency content

4.8 The human ear has a non-linear frequency response; it is less sensitive at low and high frequencies and most sensitive in the range 1 to 4 kHz (1 kHz = 1000 Hz). The convention for



summing frequency content is to apply a ‘weighting’ curve before the summation so that the different frequency components correspond with the response of the human ear. This means that high frequency and low frequency components contribute less in the summation, and the mid frequency (1 to 4 kHz) components contribute the most in the summation.

4.9 This weighting curve is called the A-weighting curve, and can be applied to measured or calculated sound pressure levels. When this curve has been applied, the signal is said to be “A- weighted”. The result is that the overall A-weighted signal corresponds more closely to the response of the human ear. If a signal has been A-weighted, then a sub-script “A” is included in the index name – so an A-weighted sound pressure level would be denoted LA.

4.10 There are a number of other frequency content indicators possible for noise analyses including isosonic curves [sones], iso-annoyance curves [noys] and other frequency weighting systems B, C and D

Time Variability

4.11 There are two straight-forward characteristics of a time varying noise signal that can be considered – the maximum and minimum. The maximum and minimum A-weighted sound pressure levels would be denoted LAmax and LAmin.

4.12 Of course, there are many levels between the maximum and minimum levels, and there is a range of different parameters which can be used to describe these. Of relevance to this project, there is the average acoustic energy and the statistical distribution.

4.13 The average acoustic energy is the hypothetical continuous sound pressure level which would contain the equivalent amount of acoustic energy as the time-varying signal being considered, and this is abbreviated to the equivalent sound pressure level, and denoted with a subscript “eq”. This average is always undertaken over a specified time period, which is included in the index name. Therefore an equivalent a-weighted sound pressure level for a one hour period would be an LAeq, 1hour.

4.14 The LAeq is expressed over common time periods for assessments of environmental noise, and these have been defined with special names:

• Lday is the LAeq assessed between 07:00 and 19:00

• Levening is the LAeq assessed between 19:00 and 23:00

• Lnight is the LAeq assessed between 23:00 and 07:00.

A further index is used in strategic noise mapping which is representative of the noise levels over a 24 hour period. In this assessment additional weighting is given to evening and night time levels to apply more importance to noise levels in these periods. The overall index is a sum of the Lday

added to the Levening levels, with the addition of a 5dB weighting, and the Lnight levels, with the addition of a 10dB weighting. The index is named Lden, where the ‘den’ stands for day, evening and night.

4.15 Another common measure of noise levels refers to the statistical distribution of the time varying signal. This is also undertaken over a specified time period, and the approach analyses the distribution of noise levels over the time period and determines for any particular noise level the proportion of the time which the noise level is above this.

4.16 The statistical analysis is often used to describe “background” noise levels, and the 90th percentile is used for this purpose. In this analysis, the noise levels are above the 90th percentile for 90% of the time period, and the index describes the quieter parts of the signal. The 90th percentile of an A-weighted sound pressure level is denoted LA90.

4.17 In the UK, the 10th percentile of the statistical analysis is used in the assessment of road traffic noise, and when applied to an A-weighted sound pressure level is denoted LA10.



4.18 There are a number of other analyses available to describe a time varying signal. Short-term noise event indicators include the peak level and sound exposure level [SEL], and longer term noise indicators include statistical indicators such as LA1, LA50, and LA99, and long-term noise event indicators including Number of Noise Events [NNE], mask index, Noise and Number Index [NNI] and the Perceived Noise Level (PNL) which is used for assessing aircraft noise levels and is calculated using noys.

Human responses

4.19 When humans hear sounds they have different responses – i.e. they may find a particular sound “pleasing” or “annoying”, and those responses can vary over time and at different locations.

4.20 In order to assess the impacts of environmental noise it is appropriate to identify a particular characteristic of the sound signal which is strongly associated with a particular human response, and to use that characteristic to be representative of the entire sound.

4.21 A significant amount of research has been undertaken to determine which particular characteristics of noise sources can be attributed to particular human responses, and these characteristics have been incorporated into the standards and guidelines for the assessment of environmental noise.

4.22 In the UK, the official method of calculating road traffic noise is contained in the publication Calculation of Road traffic Noise (CRTN) and is based on the noise index of LA10, 18h. This was shown in surveys to have the best correlation with annoyance. In EU countries, the index of LAeq

is generally used for assessing road traffic noise. However, methods to convert the UK system to LAeq are available and this is becoming increasingly used in planning new developments and undertaking appraisals of road schemes.

4.23 In the UK, the official method of calculating railway noise is contained in the publication Calculation of Railway Noise (CRN) and is based on the sound exposure level (SEL) of individual railway vehicles and individual trains. The SELs of trains are then used to calculate a LAeq,18h and LAeq,6h for daytime and night-time periods. This approach is consistent with that used in EU countries, although they may asses their LAeq levels over different time periods.

Indexes for strategic noise mapping

4.24 The EU Directive on the Assessment and Management of Environmental Noise (END) specifies Lnight as the indicator for sleep disturbance and Lden for annoyance.

4.25 The END states that in some cases, in addition to Lden and Lnight, and where appropriate Lday and Levening, it may be advantageous to use special noise indicators and related limit values. Some examples are given as:

• The noise source under consideration operates only for a small proportion of the time (for example, less than 20% of the time over the total of the day periods in a year, the total of the evening periods in a year, or the total of the night periods in a year);

• The average number of noise events in one or more of the periods is very low (for example, less than one noise event an hour; a noise event could be defined as a noise that lasts less than five minutes; examples are the noise from a passing train or a passing aircraft);

• The low-frequency content of the noise is strong;

• LAmax, or SEL (sound exposure level) for night period protection in the case of noise peaks;

• Extra protection at the weekend or a specific part of the year;

• Extra protection of the day period;

• Extra protection of the evening period;

• A combination of noises from different sources



• Quiet areas in open country;

• The noise contains strong tonal components;

• The noise has an impulsive character.

4.26 As a result of the harmonised approach adopted by EU countries, the calculated noise levels Lden

and Lnight are readily available through the strategic noise maps published by the Government. These metrics can be used to assess some noise impacts but are not appropriate for the assessment of all impacts. Instantaneous high noise levels should be considered when assessing sleep disturbance, especially when the background noise levels of an area are low.

Indexes for changes in noise.

4.27 Changes in noise can be expressed using particular notation. The difference between two noise levels can be expressed with the Level Difference D. In addition, a sound reduction index R can be obtained for a given material. The procedures for evaluating D and R are given in ISO717-1.

Assessment Input Parameters

4.28 Noise levels from environmental noise sources are variable. The levels associated with the transportation sources only occur when the vehicle or vehicles are present. Therefore, noise levels are highest when there are more vehicles present. There is a direct relationship between the number of vehicles and the noise level.

Road Traffic Noise

4.29 For road traffic in the UK, noise levels from main roads are typically a continuous ‘drone’ of traffic, and these levels would typically be higher in morning and afternoon peak periods when the volumes of traffic are their highest. Noise levels would be reasonably consistent between the morning and afternoon peaks, at a level which is often similar to the peak levels. Noise levels would drop off after the afternoon peak period to a low during the night before building up for the next morning peak period.

4.30 Driving patterns, and therefore noise levels, during the week are often different from the patterns at the weekends, and there are often subtle differences through the months of the year.

4.31 To allow a consistent basis for comparison, and to reduce the variation down to a single number, assessments of noise levels are undertaken using the total road traffic flow during the day for an average weekday in one year.

4.32 Noise levels also vary with traffic speed, the proportion of heavy vehicles, and the type and condition of the road surface.

Railway Noise

4.33 Railway noise is only generated when a train passes and is typically a series of discrete events throughout the day. The pattern of trains passing a point is dependent on the timetables for services on that line, and it is more difficult to describe a typical pattern for one day.

4.34 However, timetable patterns, and therefore noise levels, during the week are often different from the patterns at the weekends, and there are often differences between seasonal timetables.

4.35 To allow a consistent basis for comparison, and to reduce the variation down to a single number, assessments of noise levels are undertaken using the total rail traffic flow during the day for an average day based on normal operations.

4.36 Noise levels also vary with train speed, the vehicle (locomotive, carriage and wagon) types, and the type and condition of the track and its supporting structure.



Aircraft Noise

4.37 Aircraft noise follows the same patterns as railway noise, in that aircraft noise is typically perceived as a series of discrete events throughout the day. Noise levels are determined by the number of aircraft on a particular flight path, and there would be differences in these patterns between days of the week and between seasons. Aircraft noise is assessed on the total number of flights on an average summer day. Noise levels also vary with aircraft type and the particular operating characteristics.

Industrial Noise

4.38 Noise levels from industrial sources depend on the operating characteristics of the particular source. Some sources, like power stations, may operate continuously 24 hours a day for many months, generating the same noise level all the time. Other sources, such as those in quarries, may generate noises that are intermittent or occasional.

4.39 For a consistent assessment approach, noise levels from industrial sources are considered as an annual average level, which takes into account day-to-day variation, and variations throughout the year.

Noise Impact Types

4.40 In considering the valuation of environmental noise, it is helpful to identify the different impacts of noise. Not least, knowledge of the potential impacts of noise is required to establish whether different valuations of noise are mutually exclusive (i.e. whether or not there is double counting) and collectively exhaustive (i.e. whether or not all consequences are valued).

4.41 A recent Defra project report entitled ‘An Economic Valuation of Noise Pollution – developing a tool for policy appraisal’, prepared by the Interdepartmental Group on Costs and Benefits, Noise Subject Group and dated August 200824, identified four broad groups of impacts as summarised below:

• Health impacts, which includes the most severe health effects such as changes in cardiovascular mortality;

• Effects on amenity, which reflect people’s conscious annoyance arising from exposure to noise;

• Productivity losses, which relates to reduced work quality through tiredness or noise acting as a distraction;

• Environmental effects, where noise levels may impact on the functioning of the ecosystems, such as through birds breeding patterns.

4.42 In the UK, the main noise impacts currently valued in monetary terms are the effects on amenity or annoyance. However the Defra study identified health impacts of noise as a priority area for further research. In the UK, the annual cost of noise impacts on health was estimated to be between £2bn and £3bn.

4.43 The HEATCO25 study indicated that in the EU the main noise related effects with a monetary value are noise annoyance and health related effects.

4.44 The various impact groups are discussed below.

Health Impacts

4.45 It has been long recognised that there is a link between noise and health. The strongly supported hypothesis is that prolonged exposure to persistently high noise can have detrimental health consequences, both on quality of life and mortality. For example, it has been shown that high noise levels lead to high blood pressure, as well as other physiological outcomes. Whilst there is



uncertainty regarding the quantification of relationships, health effects of exposure to noise could include:

• Cardiovascular disorders (ischemic heart disease and hypertension);

• Cognitive development;

• Sleep disturbance;

• Tinnitus;

• Hearing impairment.

4.46 The difficulty in quantifying relationships is the result of numerous factors. For example, certain health impacts may only occur above a given noise level threshold or may not occur consistently across the population, e.g. men may be more susceptible to certain health effects than women, and children may not be affected at all.

4.47 There can also be difficulties in isolating the detrimental effect of noise on health from other factors. For example, many of the studies which link noise exposure to health impacts are based on road traffic noise. However, if a person is exposed to road traffic noise it is likely that they are also exposed to air pollution from the road. It is important to recognise these two health effects and, if appropriate, separate their effect.

4.48 Further challenges arise in identifying whether consequences of noise have a health, or other, impact. For example, noise can disturb sleep. Where this sleep disturbance is regular, it could lead to more serious health impacts. However, where this disturbance is occasional, the impact could be considered to have more of an effect on amenity.

4.49 The effect of noise on quality of life can be measured in terms of Disability Adjusted Life Years (DALYs). DALYs are a useful tool for measuring both morbidity and mortality effects. Therefore effects which contribute to reduced quality of life but have no mortality effects (e.g. tinnitus) can be valued using DALYs.

4.50 Although there are dose (i.e. noise exposure) and response (i.e. effect on organism) relationships for the health effects of noise which resulted from robust studies in Netherlands & Germany (Van Kempen 200226, Babish 200627), they are currently not in wide use across Europe. These relationships have undergone further investigation as part of a number of recent studies to establish whether they are suitable for widespread use. The findings of these studies are further discussed in Chapter 8.

4.51 In considering studies on health impacts of noise from different countries, it is important to recognise (and control for) cultural differences. For example, differences in diet, exercise and lifestyle may confound the health effects caused by noise.

Amenity Effects

4.52 Amenity effects arise when noise causes annoyance or disturbance. For example, they arise when noise disrupts conversations or activities such as reading, watching TV, or relaxing in the garden.

4.53 The Environmental Protection UK’s national noise survey provides examples of current sources of noise annoyance in the UK. The 2008 survey results showed that people are most bothered by noises from cars/motorbikes followed by car/burglar alarms, fireworks and children. We note that most of these sources of noise are not taken into account by strategic noise maps.

4.54 The WHO Guidelines for Community Noise23 state that few people are seriously annoyed by activities with LAeq levels below 55dB or moderately annoyed with LAeq levels below 50dB. During the evening and night the threshold noise levels for annoyance are 5 to 10 dB lower than during the day.



4.55 Local authorities have seen more than a doubling of noise complaints over the last decade28. This reflects, in part, increased awareness of the adverse effects of noise on amenity.

4.56 A significant amount of research has been carried out to quantify and value amenity effects across Europe. Research on amenity effects has focussed on road, rail and aircraft noise. The output of the research has tried to establish the level of noise which would indicate the onset of annoyance and how that annoyance would increase with increasing noise level. One possible explanation for the prevalence of research on amenity effects is that they are more readily perceived than other effects, making them easier to quantify.

4.57 The research on amenity effects has concentrated on annoyance at residential dwellings. Little information is available on the noise levels that would cause annoyance at other noise sensitive receptors such as hospitals, places of worship and recreational areas.

Productivity

4.58 A person’s productivity can be affected by noise levels that he/she is exposed to. The main factors considered here are a person’s reduced productivity due to noise causing: (1) sleep disturbance; and (2) a distraction.

4.59 It has been shown that if people are exposed to high levels of night-time noise (whether the noise is continuous, intermittent or a single noisy event) their sleep quality can be disturbed. This can result in fatigue the following day which impairs their productivity.

4.60 High noise levels, impulsive/intermittent noises, and even low level conversations can distract people from what they are doing. These distractions disrupt concentration and lead to lower productivity levels.

4.61 It is possible to value loss of productivity; however, it is very difficult to quantify the productivity loss which is a direct result of noise.

Environmental Effects

4.62 The effects of noise on local ecosystems have mainly been studied in relation to road and air transport noise. There are some studies which look at the effects of impulsive noises.

4.63 Many of the studies to date focus on one species and one source of noise. The majority of studies have found strong links between noise levels and the changing behaviour of wildlife, including breeding patterns.

4.64 Noise can have a masking effect for communication for wildlife. This same masking effect can reduce the ability of wildlife to detect the movements of predators and can lead to the population decline for wildlife which has an acoustically mediated reproductive behaviour. It is also possible that noise induced stress may be the cause of the changes of wildlife behaviour.

4.65 Extensive work has been carried out by the Dutch Ministry of Transport29 to investigate the effects of road traffic noise on bird populations. The work has led to a predictive methodology for assessing the impact of new roads on bird populations. It found that the effects on bird population are proportional to the volume of traffic but varied between species. For the most sensitive species road traffic noise can have an effect at up to 1km in woodland and over 1.5km in open-field/grassland.

4.66 It has not been possible to combine the various studies focusing on individual species due to the variations that exist between species leading to differences in reactions at a behavioural level and a population level. For example, like humans, the hearing organs of wildlife are designed to work over specific ranges of amplitudes and frequencies. Therefore each species will respond differently to different sounds. Variations also arise according to the season and to the source and context of the noise. Accordingly, at present, the environmental effects have to be dealt with on a case by case basis rather than by assessing the impact on the ecosystem as a whole.



4.67 The ecosystems services valuation method as outlined by Defra aims to improve the way in which environmental effects on ecosystems are valued. If the noise effects on ecosystems can be robustly established then it should be possible to value them. At present there are no widely recognised relationships for noise effects on ecosystems.

Noise Sensitive Receptors

4.68 A number of considerations for the identification of noise-sensitive receptors are discussed below.

Receiver Groups

4.69 Research has shown that noise could have different impacts on different groups of receptors. The main receptor groups could comprise the following:

• Age (children, adults and the elderly);

• Gender (male and female);

• State of health;

• Socioeconomic standing;

• Geographic location (climate, rural/urban, culture);

• Human vs. wildlife.

4.70 Research for children has focussed on learning performance in schools. The Dutch Group Milieumonitoring Stadsregio Rotterdam (MSR)30 notes that there are indications that long term exposure to transport noise has a negative effect on childhood learning performance. Babish27

has reviewed several studies in which the blood pressure of children was monitored however the studies were not able to confirm or rule out if exposure to high noise levels as a child will lead to cardiovascular problems later in life.

4.71 The review by Babish27 reveals that the findings for health impacts of noise on men and women can be distinguished but are not consistent across studies. Most studies to date focus on middle aged men. More research would be required to determine if noise effects on health differ by age and/or gender. Also it is not possible to conclude if health impaired subjects are more prone to further health issues due to noise exposure than healthy subjects.

4.72 Different cross-sections of the society may demonstrate different attitudes towards noise due to social, economic, cultural or other factors. These differences could result from people not formally registering their concerns about noise since they have other more pressing issues on their agenda (economics/finance) or due to different awareness levels regarding impacts of noise (education).

4.73 A study by the German Federal Health Survey31 investigated whether people of lower socioeconomic status are more likely to live in busier streets and to be more affected by traffic and noise pollution than others. The social indicators used were education, occupation, income and an index of socioeconomic status. It was found that noise pollution in environments is unevenly distributed, with people of lower socioeconomic status suffering more than others.

4.74 People living in different locations may experience noise impacts in different ways. People from urban and rural environments will generally have different noise level tolerances. Lifestyle and diet may influence the degree to which the health problems associated with noise affect receptors. Type, construction and location of house, in addition to how much time is spent outdoors, would affect the noise level that defines the onset of annoyance of different receptors.

4.75 Noise impacts will affect humans and wildlife differently due to the differences in hearing ranges and the different ways in which they use sound. These two types of receptors must be assessed separately.



4.76 Assessments typically consider the likely noise impacts at the physical environments where noise-sensitive receptors may be present, as discussed below.

Main Receiver Types

4.77 WHO23 has provided guideline values for different receptor types taking into account the health effects of noise, the sensitivity of the receptor and the duration of exposure. The main receptor types considered by WHO are listed below:

• Dwellings;

• Schools and pre-schools;

• Hospitals;

• Industrial, commercial shopping and traffic areas, including public addresses;

• Parkland, recreation areas and conservation areas.

4.78 There is a general consensus that residential properties, schools, hospitals, parkland, recreation areas and conservation areas represent noise-sensitive receptors. However industrial areas and some of the commercial developments may not be so sensitive to environmental noise since they may already be exposed to internal noise sources of their own.

4.79 When undertaking an assessment, noise sensitive receptors can be grouped into three broad headings; residential locations, other noise sensitive buildings, amenity spaces. The following lists give typical examples for each category. The lists are not exhaustive, and local knowledge of a scheme area may identify further examples.

Residential Locations

4.80 Residential locations can be broadly grouped into:

• Houses, flats and apartments;

• Hotels and hostels;

• Halls of residence and residential schools;

• Residential homes;

• Permanent caravan sites (where portable homes are installed as though they are permanent).

4.81 When people are at home they are likely to spend a proportion of their time in different rooms within their property. When measures are being considered for improvements to the building envelope, they would usually only be applied to rooms which are deemed to noise sensitive, and

guidance on this can be found in the relevant Regulations32, 33.

4.82 These regulations principally define eligible rooms as living rooms or bedrooms. In the context of the regulations living rooms include lounges, dining rooms, studies and kitchen-diners, but not kitchens or bathrooms. The regulations also define portable homes as noise sensitive locations.

Non-residential Locations

4.83 Non-residential buildings include:

• Schools (and other educational buildings);

• Churches;

• Hospitals;

• Marinas;



• Community centres;

• Caravan Parks (i.e. holiday parks rather than permanent sites);

• Marinas;

• Sports grounds buildings.

4.84 Amenity spaces include:

• Camping sites;

• Parks and gardens;

• Allotments;

• Sports grounds/pitches/tracks;

• Bowling greens.

4.85 It would also be possible to consider larger amenity spaces including nature reserves, national parks and other areas of outstanding natural beauty.

Appropriate Noise Levels

4.86 In dwellings, hospitals and other residential locations, one of the main concerns is sleep disturbance. The recommended internal noise level for bedrooms is 30 dB LAeq for continuous noise and 45 dB LAmax for instantaneous noises. High levels of continuous night-time noise can be taken into account using strategic noise mapping. The frequency and the impacts of isolated noise events can be determined by noise measurements or social surveys.

4.87 In dwellings, schools and pre-schools, and hospitals speech intelligibility and communication interference are very important as well as annoyance caused by noise which can be distracting and stressful.

4.88 New schools in the UK are now governed by the design guidelines of BB9334 which sets out noise criteria for the different indoor spaces in a school. The aim of the document is to improve the learning environment especially for pupils with hearing difficulties. Although external noise levels are not governed by building regulations, recommendations are made for external areas, which should be below 55dB LAeq during the day. The regulations aim to have certain types of indoor classrooms at levels of 30 dB LAeq during the day, and these will be difficult or costly to meet if outdoor levels are over 60 dB LAeq.

4.89 In parks and conservation areas, the critical effect is considered to be ‘disruption of tranquillity’. WHO advise that existing quiet outdoor areas should be preserved. The ratio of intruding noise to natural background sound should be kept low. These areas are often the habitat of wildlife and it can be shown that increased noise levels can have a detrimental effect on the ecosystem of an area. Consideration of quiet areas is beyond the scope of this project.

4.90 The noise levels in the WHO guidelines are a useful guideline but there may be cases where lower or higher levels are acceptable. As part of this project it is assumed that the Noise Management Areas would be situated in ‘high noise level’ areas. Therefore the following advice on sensitivity of receptors and significance of noise impacts is based on ‘noise changes’, rather than on absolute noise levels.

Sensitivity and Significance

4.91 It is described above that the human ear cannot detect changes in noise less than 1dB, and that changes in environmental noise of 3dB are noticeable. When undertaking an assessment of noise levels it is important to consider the significance of any potential changes in noise. The Design Manual for Roads and Bridges (DMRB) provides information on the significance of changes in noise in relation to road traffic noise.



4.92 The section of the DMRB which describes how to undertake a noise assessment – Volume 11, Section 3, Part 7 (HA213/08)35 provides an example of a scale to describe the magnitude of changes in noise in Table 3.1, which is repeated here.

Table 4.1 – Magnitude of Traffic Noise Changes

Noise change, dB LA10,18h Magnitude of Impact

0 No Change

0.1 – 0.9 Negligible

1 – 2.9 Minor

3 – 4.9 Moderate

5 + Major

4.93 This table indicates that changes in noise exposure described in terms of LA10,18h of less of than 1dB are negligible, and identifies that changes greater than 3dB have a higher impact than changes between 1dB and 3dB. It would be reasonable to use the same scale to describe impacts from changes in railway noise.

4.94 Current advice from the Highways Agency (IAN125/09)36 indicates that the advice on significance presented in DMRB Volume 11, Section 2, Part 5 (HA205/08)37 may not be applicable to noise assessments, and therefore the impacts would have to be assessed on the magnitude of changes in noise.

4.95 However, it is described above that the human ear cannot detect changes in noise level of less than 1dB (in the short term), and that changes in environmental noise of 3dB are noticeable in the long term. This information could form the basis of a significance scale to assist in summarising comparisons between schemes or options.

Table 4.2 – Significance for Changes in Noise

Noise change, dB LA10,18h Magnitude of Impact Significance

0.1 – 0.9 Negligible Neutral

1 – 2.9 Minor Slight

3 – 4.9 Moderate Moderate

5 + Major Large

4.96 Equally, it would be reasonable to assign the same significance to changes in LAeq,18h for railway noise.

Chapter Summary

4.97 This chapter has set out definitions of the relevant acoustic parameters, and summarised the requirements for source input data for calculations. It has highlighted the various types of impact which noise can have, and set those in the context of different types of noise sensitive receptor. Finally, guidance is given on the significance of changes in noise.



38

5. The Assessment Process

5.1 In order to determine the cost-effectiveness of noise control measures for a noise management area it is necessary to undertake an assessment. It is proposed that such an assessment would be carried out in two stages. Initially, a scoping exercise would be undertaken to consider, broadly, which types of noise control measures would be suitable in a given situation. Following this, a more detailed assessment would be used to quantify the potential noise reductions and to assist in the decision making process. This chapter describes the assessment process, and sets it in the context of the project. The advice presented here is developed into a toolkit which is presented in Chapter 11, with a worked example in Chapter 12, and case studies in Chapter 13.

Design Targets

5.2 The Action Planning guidance in the UK9-22 does not set specific design targets for controlling noise. However, when noise control measures are being assessed, and selecting which design options to take forward to a cost benefit analysis, it is useful to think about potential reductions in noise level, and to take a view taken on whether these would be suitable for the noise management area, and whether the noise benefit offered would be significant (i.e. that reductions in noise would be at least perceptible).

5.3 For the person who is designing the potential noise control options it is often useful to have a design target in mind, so that they can iteratively adjust the noise control measures to aim towards that target. This also allows demonstration of the overall performance of the control measures and that they serve the purpose for which they were intended.

5.4 It is not the purpose of this project to suggest potential noise control design targets, but a number of example targets are given. Design targets should be referenced with the information on absolute noise levels and significance of changes in noise levels presented in Chapter 4 of this report. Broadly speaking design targets would either:

• Aim to reduce noise levels below an absolute noise level or

• Aim to achieve a reduction in noise levels of at least a certain amount.

5.5 Example noise design targets in terms of LA10, 18hr are given in the Highways Agency AMM43 which describes Highways Agency’s 6-stage Hotspot Noise Assessment process. The Stage 5 of the methodology ranks the potential benefits of different levels of action which could reduce LA10,18h noise levels by varying degrees, for example:

• “Sufficient to reduce exposures by the noise exceedance assessed under sift criterion;

• A significant reduction (at least 2 dB) at worst affected properties;

• Sufficient to ensure no property exposed to more than 75 dB(A);

• Sufficient to ensure no property exposed to more than 72 dB(A);

• Sufficient to ensure no property exposed to more than 68 dB(A)”.

5.6 In the context of action planning, the following example design targets could be used to inform the noise control design process:

• A reduction of at least 3 dB LAeq at worst affected properties;

• Sufficient to ensure no property exposed to 73 dB LAeq, 18hr for rail sources;

• Sufficient to ensure no property exposed to 76 dB LA10, 18hr for road sources;

• Sufficient to ensure all properties are below the threshold for Noise Management Areas.



5.7 Ultimately though, the design target is simply a tool to determine if the proposed noise control measures are ‘fit for purpose’ or not. When noise mitigation is being designed it may become obvious that the design target can be met at all but a small number of properties due to the constraints in place, and that the target may be exceeded at a number of other properties. For the purposes of a cost benefit analysis, what is important are the reductions in noise levels at the properties, rather than the target that was used to get to this point. The person designing the noise control measures needs to have a clear idea of what reductions in noise would be “acceptable”.

Assessment Years

5.8 The regulations4-8 do not provide guidance on the choice of assessment years. There is a requirement for action plans to be revised every five years and this may be a convenient basis for determining the assessment years. For example the year marking the end of a particular action planning period could be adopted as the ‘baseline year’. It could be assumed that the planned noise control measures would be implemented by this year.

5.9 It is required as part of a cost benefit analysis to reflect the design life of noise control options and the noise benefits achieved in the long-term. This is achieved by the selection of an appropriate ‘future assessment year’.

5.10 For the purposes of cost benefit analysis of remediation measures, the following assessment years could be adopted:

• Baseline year – the year marking the end of an action planning period, when all planned control measures in that period would have been implemented;

• Future year– 60 years after the baseline year to represent the expected whole-life costs (this appraisal period is recommended in TAG Unit 3.5.439 for transport investments). The ‘noise changes’ beyond the baseline year would be assumed to remain constant except where a traffic model is used to predict changes in traffic flows with the measure.

5.11 For example, the DfT TAG methodology for noise uses the concepts of Opening Year (year 0 or the year in which the benefits of the intervention come on line) and future Forecast Year (usually 15 years after opening). In between the Opening Year and the Forecast Year, appraisers are required to use linear interpolation to predict the profile of growth in noise levels and hence the noise changes over time.

5.12 However, the full appraisal period (also known as the horizon year) for which a valuation is required could be much longer, to reflect the expected asset life of a scheme (in the case of A3 Hindhead scheme for instance, this is stated to be 60 years). After the Forecast Year, noise profiles are assumed to remain flat since no reliable noise predictions are possible beyond this point.

Scoping

5.13 The first step in the assessment process is to undertake a scoping exercise. The objective of the scoping is to become familiar with the area, and to identify any particular constraints which may limit the options for noise control measures.

5.14 The purpose behind becoming familiar with the area is to enable an accurate assessment of the potential benefits of noise control measures. It is important to identify which noise sources are in the area, and where the noise sensitive locations are. The constraints are useful to exclude particular measures which are not suitable at an early stage.

Noise Source Identification

5.15 The strategic noise maps include the noise sources at a suitable level of detail for the requirements of the Environmental Noise Directive. In certain situations there may be additional



noise sources affecting the local community which have not been included in the strategic noise maps.

5.16 The noise control design process should consider these noise sources and their effect on the community. If there are two or more different sources which contribute similar noise levels at a location, then the overall improvement in noise levels will be limited if only one source is mitigated. The noise sources to consider could include roads or railways with flows below the thresholds for strategic noise mapping, or there may be a significant contribution from aircraft noise. Also, there may be other types of noise sources which are not included in the scope of this project.

5.17 An assessment should be made of the relative importance of all of the noise sources in the noise management area, and a decision made about which ones to include in the noise modelling process.

Noise Sensitive Receiver Identification

5.18 When designing noise control measures it is important to consider the noise sensitive receptors which are in the noise management area. This will include residential properties, but there may be a number of non-residential properties which are noise sensitive. A list of non-residential noise sensitive receptors is given in Chapter 4 of this report, but other types of receptors could be added to this list.

5.19 Local knowledge should be able to identify all of the noise sensitive receptors, both residential and non-residential. Separate design targets may be set for residential and non-residential receptors.

5.20 Acoustically speaking, the weakest points on the facades of buildings are often the windows, and to a lesser degree, doors. When the internal noise environment is being considered, it is useful to note facades of buildings without windows and/or doors.

5.21 It is important to accurately consider the number of floors in each building, and to estimate the height above ground level for each floor. This is particularly important when noise barriers are being considered, and it is useful to observe properties which have had loft conversions, as these would usually include bedrooms or other living rooms.

Constraints for Noise Barriers

5.22 The most obvious constraint for noise barriers is requirements for access. It would be impractical to place a barrier to protect a row of houses from a road if each house requires access from its front door directly onto that road. Other constraints may exist, which are described in Chapter 10 of this report.

5.23 In instances where there are noise barriers (or other features providing screening) already in place, then it may be difficult to get significant improvements in noise levels.

Constraints for Road Surfaces

5.24 The full acoustic benefits of quieter road surfaces are realised at higher traffic speeds and low compositions of heavy goods vehicles. If the section of road being considered has slow moving traffic or congested conditions, then the benefits of quieter road surfaces would be more difficult to realise.

5.25 If the road already has a quieter road surface, then potential improvements would depend on the acoustic performance of the existing quieter road surface.

Constraints for Building Envelope Improvements

5.26 The biggest potential improvements for building envelope treatments would be at buildings with single glazed windows, particularly sash windows. Where a building has non-openable double



glazed windows and an alternative means of ventilation, then improvements in the building façade are unlikely to be practicable.

5.27 Where properties have loft conversions, mansard roofs or dormer windows, then these may also be acoustically weak, and window treatments may provide limited benefits.

5.28 In order to assess the potential benefits of door and window improvements, it is important to note the existing types of windows in the buildings where this measure is being proposed.

5.29 Where noise sensitive rooms have external doors there may also be a requirement to acoustically treat these in addition to any windows. This may include patio or balcony doors, or where the front or back door to the property leads directly to a noise sensitive room.

5.30 Ultimately, this type of measure would require a detailed investigation of the relevant properties to identify which windows and doors are for noise sensitive rooms, and which are for non-noise sensitive rooms or communal spaces within the building.

5.31 Within these constraints in mind, it is important to note that there is no method available for valuing changes in internal noise levels.

Scenarios

5.32 When assessing potential noise reductions, a number of different scenarios should be considered, so that the noise control measures can be optimised. The scenarios could be investigated under ‘Do-minimum’ and ‘Noise Control’ scenarios. Each scenario would therefore require its own design target.

Do-Minimum Scenario

5.33 The first scenario which should be considered is a “do-minimum” scenario. In this scenario the noise management area should be reviewed in light of programmed maintenance activities and schemes or developments that are planned which may affect the area.

5.34 An assessment should consider if these activities or schemes would give rise to changes in noise in the noise management area, and these changes should be compared with the design target.

Design Target Met

5.35 If the activities or schemes result in reductions in noise which meet the design target, a review of the proposed maintenance works, schemes and developments should be undertaken to establish which are “certain” and which are “uncertain”, i.e. which are already planned and funded (i.e. committed schemes), and which are subject to further planning or funding, or are dependent on some other external constraint. This review effectively determines the level of risk that these works/schemes/developments go ahead and have the resultant improvement in noise levels.

5.36 As an example, there are planned resurfacing works within a five year window which would reduce existing noise levels by 2dB. In addition an outline scheme is proposed elsewhere in the region which would re-distribute traffic and give rise to a 2dB reduction in this area. The design target is to reduce noise levels by at least 3dB at the worst affected locations. Should both go ahead, there would be a 4dB reduction in noise levels, and this would meet the design target, but there is a level of risk that the scheme would not go ahead, and therefore the design target would not be met. The schedule of planned resurfacing works could be examined to identify if these could be brought forward.

5.37 If the design target is met, then other noise control measures do not need to be designed, and this can be reported. The noise control strategy becomes one of potentially re-programming existing planned activities, and potentially supporting schemes or developments which contribute to the improvement in noise levels.



Design Target Not Met

5.38 If the activities or schemes result in increases in noise, or reductions in noise levels which are below the design target, then further noise control measures are required to meet the design target.

5.39 The noise control measures should then be based on the do-minimum situation, so that the overall noise targets can be met.

Noise Control Scenarios

5.40 For the purposes of identifying suitable noise control measures, it is useful to consider at least two different noise control scenarios. The first scenario could have a tightly focussed design target, perhaps to offer a small reduction in noise at a few properties. The second scenario could have wider aims to offer greater reductions in noise or to consider greater benefits at a number of properties.

5.41 By adopting two scenarios in this manner, it is possible to compare two different levels of spend on noise control measures and to compare them with their relevant benefits.

5.42 In the development of the noise control measures more than two scenarios may be required, especially if there are a number of different locations within the noise management area which could be treated. The number of options should be agreed, and design targets set for each.

5.43 For each scenario, there may be a number of different noise control approaches which could meet the design target, and these should each be tested and reported separately.

5.44 For the purposes of this report it will be assumed that two scenarios are being considered, a “focussed” scenario, where the noise levels are being controlled at a concentrated area, and a “broader” scenario where improvements in noise level are being sought over a wider area within the noise management area.

Focussed Scenario Example

5.45 For a focussed scenario example, the design target could be to reduce the noise levels by a small amount at the worst affected properties. The noise control measures could be designed to give at least a 3dB reduction in noise levels at those buildings with the highest noise levels. Specifying a reduction in noise greater than 3dB would be desirable.

Broader Scenario Example

5.46 For a broader scenario example, the aim could be to reduce noise levels to below an absolute noise level at all properties within the noise management area. The scenario should recognise that in some places this will not be easy to achieve. In this case, the aim should be to provide as large a reduction in noise as is reasonably practical at properties where the absolute noise level target cannot be reached.

Study Area

5.47 Once the scenarios and targets have been defined, it is important to ensure that an appropriate study area is defined.

5.48 The study area should include all properties where changes in noise of 1dB or greater are expected. In practice, the study area should be extended slightly further than this to include properties where the change in noise is less than 1dB and to positively demonstrate the extent of the study area.

5.49 The toolkit provides information on likely study area sizes for different noise control measures, but if the assessment shows that a larger study area is required, then this should be adopted in order to assess all of the changes in noise equal to or greater than 1dB.



Calculations

5.50 Calculations should be undertaken to determine the level of noise control required to meet the design target, and to identify the extent over which changes in noise level are experienced.

5.51 In all cases, noise levels should be calculated to the nearest 0.1dB. The toolkit provides details on the methodologies to be used for each type of noise control measure. Where noise levels are being calculated to be representative of buildings, façade noise levels should be calculated. Where noise levels are calculated to be representative of amenity spaces, free-field noise levels should be calculated.

Residential Properties

5.52 A sufficient number of calculation points should be selected to be representative of all dwellings in the study area. There are two approaches to this, either a separate calculation can be undertaken at every dwelling in the study area, or calculations can be undertaken at a smaller number of locations where each calculation is representative of a number of properties. In some situations there will be more than one calculation point at some buildings.

5.53 The height of the ground floor level, and the interval for higher storeys will have been determined from the scoping exercise. Calculations should be undertaken at 1.5m above each floor level.

5.54 Where a property has more than one façade, the results on the façade with the highest noise level should be reported, and the benefits of the noise control measures should be assessed against this highest noise level.

5.55 Where a property has more than one storey, the benefits of the noise control measure should be assigned to the floor with the smallest benefit. Where barriers are being considered, this will usually result in the top floor of the property being considered as demonstrating the benefit.

5.56 It is acknowledged that in certain areas the benefits on facades with lower noise levels, or at other floors may warrant particular mention when considering the noise control option, and these can be reported separately, but for the purposes of the cost benefit analysis it is important that the calculations of the highest noise level with the smallest benefit are representative of that property.

5.57 When undertaking the assessment it should be ensured that all properties in the study area are included in the results, and that correct calculations are assigned to each property.

Non-Residential Properties

5.58 Where non-residential noise sensitive buildings are included in the noise assessment, these should be treated in the same manner as residential buildings. The objective is to identify the façade of the building with the highest noise level, and then to identify the smallest change in noise level on this façade.

5.59 Where the non-residential property is substantial, for example a large school, it may be appropriate to sub-divide the property into a number of sections, and calculations can be reported for each section separately.

5.60 When undertaking the assessment it should be ensured that all non-residential noise sensitive properties in the study area are included in the results, sub-divided where appropriate, and that correct calculations are assigned to each one.

Amenity Spaces

5.61 Where amenity spaces are included in the assessment, for example parks, it may be appropriate to consider one calculation point if the area is quite small, or it is known that noise levels do not vary significantly across it. Where the space is larger or if noise levels are known to vary across its area then more than one calculation point may be required. Calculations should be undertaken 1.5m above local ground level.



5.62 For the larger amenity spaces, where noise levels are being represented by more than one calculation point, the benefits from the noise control measure will need to be reported carefully, particularly where noise control is intended to protect only part of the amenity space.

Presentation of Results for Assessment

5.63 Once the calculations have been completed, and the noise control options being considered are deemed to have met the design targets, the results need to be summarised for reporting and the cost benefit analysis.

5.64 Effectively there is a maximum of three groups of results, residential properties, non-residential noise sensitive buildings, and noise sensitive amenity spaces. For each group of results a summary table should be prepared in line with the tables given in the DMRB chapter for noise (HA213/08) for a simple level of assessment. In this study, the existing situation is being compared with a number of other scenarios, including a do-minimum scenario, and the headings of the columns should be changed accordingly.

5.65 Separate tables should be prepared for each noise control option being considered, and for each scenario undertaken, and this allows the changes in noise for each scenario and option to be compared.

5.66 The DMRB tables include lines for changes in noise less than 1dB. In this study, such changes are not being considered, however these lines should be completed with the data, so that the total number of properties can be shown to be consistent over each option.

5.67 The ‘total’ lines at the bottom of the table should be adjusted to report the total number of receptors with changes in noise greater than or equal to 1dB, and additionally to present changes in noise greater than or equal to 3dB.

5.68 The example table given below is for road traffic noise, and refers to the LA10, 18hr. For rail studies, the table should refer to LAeq, 18hr.

Table 5.1 – Template for Summarising Changes in Noise

Option/Comparison:

Receptors subject to a change in noise level:

Number of dwellings Number of non- residential buildings

Number of amenity spaces

Change in noise level, LA10,18h dB

Increase in noise level

Decrease in noise level





0

0.1 – 0.9

1 – 2.9

3 – 4.9

5 +

Total (change 1+)

Total (change 3+)

5.69 In order to undertake the valuation of the acoustic benefits for each option and scenario, a more detailed list of results is required. This is discussed further below and an example valuation calculation is given in Chapter 8.



Residential Properties

5.70 For each calculation point, three data columns are required, and optional descriptive columns may be useful to the analysis. Optional columns are often included first and show calculation references and a description of the calculation which could include the address, façade and floor levels.

5.71 The first data column should be the current, or existing, noise levels – i.e. the noise levels before the noise control measures are in place, and before consideration of any do-minimum works.

5.72 The second data column should be the future noise levels. For the do-minimum scenario, this would be the do-minimum noise levels, and for each of the noise control scenarios this would be the “with measures” noise levels.

5.73 The third data column should contain the number of residential properties which that calculation point is representative of.

Table 5.2 – Example Results for Valuation

ID Address Floor Do-min Noise

With Meas. Noise

No. of Properties

238 Tower Block A 0 58.6 53.2 2

238 Tower Block A 1 59.0 55.3 2

238 Tower Block A 2 59.3 56.7 2

238 Tower Block A 3 59.5 57.8 2

238 Tower Block A 4 59.8 58.5 2

238 Tower Block A 5 59.9 59.2 2

238 Tower Block A 6 60.1 60.0 2

239 102 High Street 0 70.8 62.9 0

239 102 High Street 1 77.3 72.4 4

240 56 Church Road 0 69.9 71.2 0

240 56 Church Road 1 75.2 76.4 2

241 6 Dunroamin Drive 0 71.0 67.0 3

5.74 The list of results should be processed so that the number of properties in 3dB bands is given, following the advice in TAG unit 3.3.240. The description of the process to assess the change in valuation of a property following an increase or decrease in noise levels, is given in Chapter 8 along with an example valuation (from paragraph 8.62 to 8.84) for the results at calculation point ID241, 6 Dunroamin Drive.

5.75 It should be noted that the supplementary guidance in the TAG unit60 provides a method for considering the noise analysis in 1dB bands. This approach may be used, but if the results are going to be cross-compared with other studies which have used the 3dB bands, then care would need to be taken that the comparisons were on a like for like basis.

5.76 The advice in this report assumes that the 3dB band approach is being used. Change bands greater than 3dB should not be used. The supplementary guidance in TAG unit 3.3.2 gives a worked example where the valuation of noise results has been undertaken using both a 1dB band width and a 3dB band width. The overall results were within 1% of each other.



5.77 The version of the TAG spreadsheet on the DfT web site assumes a 15 year period between opening and the future year assessment. It is unlikely that future traffic forecasts will be available for the majority of noise management areas. If using the spreadsheet from the DfT website, then the results of the assessment should be copied into both the opening and design year, which would therefore assume that noise levels are not going to change.

5.78 In reality, noise levels will change due to changes in traffic, however unless the noise control measure affects traffic flows, the noise levels would change by the same amount with and without the scheme.

Non-residential buildings

5.79 Currently, there is no method available to undertake a valuation of non-residential buildings. The results for this group of receptors can be considered in terms of the significance of the results, and if there are any changes in noise which are significant, these can be included in the cost benefit analysis as an unvalued impact.

Open Spaces

5.80 This project focuses on noise management areas which are likely to be significantly above 55dB LAeq or LA10, and therefore the valuation method identified for amenity spaces will not show any benefits unless noise levels are reduced to levels below this threshold. If it is deemed important to consider benefits in open spaces where noise levels can be shown to be below this threshold, then the following method may be used41;

5.81 The valuation method calculates a disbenefit for the space on the basis of the proportion of the space with noise levels over 35dB, based on a willingness to pay for undisturbed nature. The method uses a linear interpolation between 0euro/m2 at or below 35dB and 0.3euro/m2 at and above 55dB. The method is based on change in LAeq, but could equally apply to change in LA10 for road traffic noise.

Costs of Noise Control Measures

5.82 It is necessary to estimate the costs of each of the noise control measures being considered. The toolkit provides advice on the steps that need to be undertaken. Chapter 6 of this report gives a description of methods available for controlling noise. Chapter 7 provides some indicative costs for different types of noise control measures.

Value of Noise Changes

5.83 Suitable monetary values would need to be selected for noise changes to be used in a cost benefit analysis. Chapter 8 discusses the main considerations and makes recommendations.

Non-acoustic Assessments

5.84 The toolkit provides advice on what other assessments may be required for the noise control measures. These would need to be undertaken, and the results summarised for the cost benefit analysis. Chapter 9 gives advice on other assessments that may be required.

Cost Benefit Analysis

5.85 The results of the noise assessment need to be brought together with the costs of the noise control measures being considered, and the results of any non-acoustic assessments undertaken. A framework for undertaking this is provided in Chapter 10.

5.86 Overall, the process should optimise the net benefits, and each scenario should be examined individually to ensure that this is the case. It may be appropriate to undertake a number of iterative calculations so that the optimum benefits can be determined, within the constraints of the scenario.



5.87 Iterations may involve changing the scale or type of noise control measure, re-defining the study area or selecting a different design target for the scenario.

Reporting

5.88 A brief report should be prepared for each noise management area to allow a decision to be made on the selection and prioritisation of the noise control option. This report should describe the existing situation and noise levels, and the different noise control options investigated. The results of the assessments should be presented along with the results of the cost benefit analysis. The following report structure is suggested:

• Introduction, describing existing situation and noise levels;

• Planned works and schemes, describing any do-minimum activities;

• Scoping, describing the results of scoping exercise including measures excluded;

• Scenarios considered, describing each of the scenarios considered;

• Results, description and summary table for each scenario/option, and any key features, and estimation of costs for each noise control measure;

• Non-Acoustic Studies, description of non-acoustic studies and key results;

• Cost Benefit Analysis, the cost benefit analysis and results.

Chapter Summary

5.89 This chapter has described the approach which should be adopted when considering the cost effectiveness of noise control measures. The approach defines what needs to be included in the assessment, the necessary noise calculations which need to be undertaken, and how those results should be presented.

5.90 Further, the method describes how the results of the noise assessment should be combined with the results for other assessments, and the cost benefit analysis undertaken. It is highlighted that different scenarios need to be considered in the cost benefit analysis, and that a number of iterations may be required to determine the most cost-effective noise control measure.



6. Methods of Controlling Noise

6.1 There are various noise control measures which could be applicable to road and rail related noise sources. Some of these have been highlighted in the Draft Action Plans for England12-14 published in July 2009 (major roads, major railways and agglomerations). Practical guidance and advice would be required, both at policy level and Local Authority level, for the cost-benefit analysis of measures.

6.2 A detailed review of various types of noise control measures has been undertaken as part of this project and the findings are given in Appendix B. The review focussed in particular on actions for road traffic noise and railway noise including light rail systems such as trams. The detailed review of building improvement measures is presented in Appendix F.

6.3 The objective of the review was to identify suitable noise control measures which would be considered in the project as part of case studies and toolkits for the demonstration of a cost benefit analysis for noise remediation strategies. The discussions of various noise remediation strategies identified the following measures to be taken forward in the project for road and rail noise sources:

• Rail grinding and wheel turning (rail);

• Rail pad replacement (rail);

• Alternative road surfaces (road);

• Altering traffic flow (road);

• Imposing vehicle restrictions (road);

• Speed restrictions (road);

• Noise barriers (road and rail);

• Building envelope improvements (road and rail).

6.4 The shortlist of measures concentrates on those which would be applicable to existing noise problems within a local or regional context and could give rise to noticeable acoustic benefits immediately after implementation or after a brief transition period. The potential benefits of general street-works and street maintenance have not been considered further since the effects on the long term average noise levels are not well established. Measures associated with land use planning and management or building design also have not been considered further since these would not be applicable to existing noise problems.

6.5 The following is descriptive of how acoustic effectiveness of each measure could be assessed. The potential acoustic benefits and other non-acoustic considerations are further explained in Appendix B

Rail Grinding and Wheel Turning

6.6 When determining train pass-by noise levels, for a given track-vehicle combination and train speed, the measured noise has contributions from the vehicle (mainly the wheels) and a contribution from the track (mainly the rail and sleeper). The dominant mechanism for noise generation is rolling noise and this is generated from vibrations resulting from wheel-rail interaction and is emitted both by vehicle and track components. The interactions at the wheel/rail interface can create the generation of roughness and in particular cases corrugation on the rail and wheel. These imperfections can raise the noise level by 10 to 20 dB LAeq. Regular



maintenance in the form of rail grinding and wheel turning can significantly reduce noise levels generated by the wheel/rail interaction.

6.7 The potential benefits could be taken into account in the assessment process by assuming a correction factor for the relevant rail segments42.

Rail Pads

6.8 Rail pads are formed of resilient material, and are located directly beneath the rail at every sleeper. It has been demonstrated that the use of stiffer rail pads combined with appropriate rail fastening systems can reduce noise emissions from the track43. Reductions of up to 6 dB have been recorded.

6.9 The potential benefits could be taken into account in the assessment process by assuming a correction factor for the relevant rail segments.

Alternative Road Surfaces

6.10 The benefits of lower noise surfaces could be modelled by assuming a ‘correction factor’ for the relevant road segments. In instances where the noise benefits vary for different classes of vehicles and at different speeds, there may be a need to account for these effects separately.

6.11 DMRB 11:3:735 recommends the use of 3.5 dB as a potential correction term to represent the potential benefits from the thin wearing course type surfaces at traffic speeds above 75 kph. Although it is likely these would provide potential benefits at lower speeds, there are no reliable estimates available at lower speeds in DMRB. The guidance gives no advice on the potential effects of traffic flow composition on the performance of thin wearing courses.

6.12 Further advice on potential correction factors which could be assumed are given in EffNoise report44.

Altering Traffic Flow and Imposing Vehicle Restrictions

6.13 The effects of traffic flows and composition can be modelled using standard calculation methodologies such as CRN45 and CRTN46. Assuming there are no other changes to the traffic, a 20% reduction in traffic flows would result in a noise reduction of 1 dB and a 50% reduction would give a 3 dB benefit.

Speed Restrictions

6.14 The reductions in mean traffic speeds along a section of road as a result of traffic calming measures could be modelled using standard calculation methodologies such as CRTN. A reduction in speed from 50 kph to 30 kph could result in noise reductions of approximately 2 dB on roads with no significant amount of heavy goods vehicles.

6.15 However the localised effects in peak or maximum noise levels may need to be determined through measurements or estimated from other studies. These effects would depend on the method of traffic calming employed and are described in Appendix B.

Noise Barriers

6.16 The CRTN and CRN models can be used to assess the screening by simple reflective and absorptive barriers, which take into account characteristics of typical road and rail noise sources as well as the site geometry. Although these calculation methods could give theoretical benefits in excess of 20 dB, the actual performance of well-conceived barriers could be limited to 5 to 10 dB in practice.

6.17 Tunnels could be modelled by effectively assuming that there is no traffic along the relevant section of road or railway (i.e. traffic is fully screened). The reverberant noise build-up within the



tunnel could increase the noise levels near the tunnel portals and this effect should be taken into account 55.

6.18 For alternative barrier types where a simple ‘path length difference’ approach is not applicable, there may be a need to allow for the barrier screening effects empirically. The acoustic benefits could be simulated by adding a notional height to the existing barrier. Further detail is given in Appendix B12.

Noise Insulation of Properties

6.19 In housing, openable windows are commonly used for ventilation, and in these cases, noise level difference between inside and outside are likely to be in the range 10-15dB when such windows are open.

6.20 Where a window has poor sealing, its performance can be improved by rectifying the sealing. Further information on the potential level of noise reductions has been reviewed and is presented in Appendix F. In summary, the review gives:

Table 6.1 – Summary of Glazing Performance

Glazing System Performance range (units are Rw, RA(traffic), DdBA or D100-3150Hz)

Partially open window 8 to 15

Partially open secondary glazing system 20 to 25

Single glazed window 22 to 34

Double glazed window 26 to 36

Secondary glazing (unspecified) 34 to 41

Secondary glazing (both single glazed) 35 to 51

Secondary glazing (single and double glazed) (33 with poor sealing) 46 to 52

6.21 On the basis of the information given in Appendix F, the following table of benefits has been derived. The derivation of these benefits is described in detail in Appendix F.

Table 6.2 – Assumed Acoustic Benefits for Window Improvements

Existing System Proposed System Improvement

Single Glazing (closed) Replace: Double Glazing (closed) 5 dB

Single Glazing (partly open) Add: Secondary Glazing (partly open) 10 dB

Single Glazing (partly open) Add: Ventilation (window closed) 15 dB

Single Glazing (partly open) Replace: Double Glazing, Add: ventilation (window closed) 20 dB

Single Glazing (partly open) Add: Secondary Glazing and ventilation (window closed) 20 dB

Double Glazing (partly open) Add: Ventilation (window closed) 15 dB

Double Glazing (partly open) Add: Secondary Glazing and ventilation (window closed) 15 dB

Secondary Glazing (partly open)

Add: Ventilation (window closed) 15 dB

Sealed Single (closed) Replace: sealed double glazing (window remains closed as alternative ventilation provided)

5 dB

Sealed Double (closed) None required 0 dB



6.22 The majority of properties in the UK have some form of double glazing, and the conversion from

single to double glazing is limited to some 27% of properties.

6.23 On the whole, properties are naturally ventilated, and this typically includes the use of windows to provide ventilation either via trickle ventilators or by opening the windows. Therefore, the acoustic benefits from the provision of alternative forms of ventilation, allowing windows to remain closed is available to the majority of properties. Acoustic performances can be improved further by eliminating trickle ventilators.

6.24 An initial starting point would be to assume a benefit of 15dB, representative of providing alternative ventilation to dwellings with existing double glazing.

6.25 At the detailed design stage, a review of buildings and their current glazing and ventilation strategies should be reviewed, and these can then be assessed in more detail, using the data in Table 6.1 and Appendix F. At this higher level of detail, where properties have single glazing, the acoustic benefits can be higher than the initial starting point, and where properties have balanced mechanical ventilation systems the acoustic benefits could be lower than this.

Chapter Summary

6.26 This chapter has set out the main noise control measures considered for this project, which are:

• Rail grinding and wheel turning;

• Rail pad replacement;

• Alternative road surfaces;

• Changing road traffic flows and speeds;

• Noise barriers;

• Building envelope improvement measures.

6.27 In each case the method of calculation and potential acoustic benefits are outlined.



7. Costs of Noise Control Measures

7.1 The direct costs associated with the whole life costs of noise remediation measures include, among others, design, construction, implementation, operation, maintenance, removal, renewal and replacement costs.

7.2 Some of the new types of lower noise road surfaces may need replacing earlier than more traditional road surfacing materials. The initial costs of some types of barriers may be much higher. When considered in context of whole life costs, there may not always be a significant difference between various materials. For instance a concrete barrier may be more expensive than a timber barrier but may last longer.

7.3 In order to assist the costing of noise remediation measures, this chapter provides indicative costs for various components of noise remediation measures. The indirect costs associated with various measures are discussed in Chapter 9.

7.4 The costs below are typical average values based on past project experience, market research and information available in the literature. The actual costs would depend on a number of site specific factors, particularly quantities required and the size and type of project, and will vary slightly between regions and with prevailing economic circumstances.

7.5 The costs below are intended as guide values only to enable cost comparisons of options. The analyst would need to be satisfied that these values are appropriate for the project under consideration. Empirical data from local similar projects should be used, where available. The measures described below typically include:

• Purchase costs of the measure;

• Costs associated with the foundations or support for the measure (although these costs assume simple foundations rather than complex situations e.g. on embankment or attached to an elevated structure);

• Installation of the measure.

7.6 The costs do not include:

• Design of the measure or supervision costs;

• Any costs associated with installing the measure on a live transport link (i.e. traffic management or possession costs) or disruption from such installation (i.e. train operator disruption costs);

• Provision of any protection for the measure (safety fences etc.);

• Other required assessments, approvals or planning costs;

• Maintenance costs through the life of the measure;

• Operational costs (e.g. Electricity supplies);

• Any consultation costs with stakeholders or the general public;

• Any costs related to the diversion/protection of the statutory utilities;

• Risk or contingency in the process.

Cost of Screening Noise Control Measures

7.7 Indicative unit costs of screening noise control measures for road traffic noise and railways are provided in Table 7.3 to Table 7.5.



7.8 In addition, the total costs for each measure will need to include costs for planning, approvals, design and professional fees and disruption. On the basis of project and industry experience, the following indicative guideline allowances may be used. Allowances given are a percentage of the supply and installation costs of the barrier, from Table 7.3.

Table 7.1 – Cost Allowances for Roadside Barriers

Allowances assessed Percentage Allowance

Highway Authority Approvals 10%

Design/Consultancy/Professional fees 12%

Traffic Management Costs 20%

Protection (safety barriers) 10-15%

Risk/contingency 10%

Table 7.2 – Cost Allowances for Lineside Barriers

Allowances assessed Percentage Allowance

Network Rail Planning and Approvals 10%

Design/Consultancy/Professional fees 12%

Train service/ Train operator disruption costs (Schedule 4 of Railways Act 1993)

10%

Risk/contingency 10%

7.9 The data in Table 7.3, relating to barriers, gives costs for 3m high barriers, from Watts78. There is limited data available for costs of barriers of other heights, but on the basis of data obtained from other projects, it would be reasonable to allow a reduction in barrier cost of 15% per half metre reduction from 3m, and an increase in barrier cost of 25% per half metre increase above 3m.

7.10 As an example, a 3m single leaf reflective barrier is given as £210 per linear metre. A 2m equivalent would be 30% less at £147 per linear metre, and a 4m barrier would be 50% more at £315 per linear metre.

7.11 Barrier cost estimates for one project where a barrier was to be installed on a structure indicated that costs were significantly above the values given in Table 7.3. Where barriers are proposed for locations where anything other than simple foundations are required, then the requirements and costs for providing the barrier support should be established with an appropriate civil or structural engineer.

Cost of Noise Control Measures for Road Traffic Noise

7.12 Indicative unit costs of noise control measures for road traffic noise are provided in Table 7.6 to Table 7.12, as follows:

• Table 7.6 on road surfaces

• Table 7.7 to Table 7.11 on traffic calming measures

• Table 7.12 on traffic management.

7.13 The costs expressed in Euros can be approximately related to Pounds Sterling by multiplying these using a factor of 0.68. This is based on the historic exchange rates between 2004 and 2007. The exchange rate current in May 2009 was approximately 0.89.



Table 7.3 – Noise Barriers

Description Estimated price/ unit Cost year Design Life Reference Ref Year Comment

(Generic) 300 EUR/m2 - note 1 SILENCE 2007 Construction and material?

Reflective timber noise barrier, single leaf

£210/m length/ 3m high - note 1 Watts et al 2005

Reflective timber noise barrier, double leaf


Absorptive timber noise barrier, single leaf


Reflective concrete barrier £360/m length/ 3m high - note 1 Watts et al 2005

Partially absorptive vegetative barrier, living willow

£360/m length/ 3m high - note 1 Watts et al 2005 Costs of water and annual pruning not included

Partially absorptive vegetative barrier, ivy covered

£415/m length/ 3m high - note 1 Watts et al 2005 Costs of water not included. After 3 years no further irrigation required.

Absorptive aluminium panels £575/ m length/ 3m high - note 1 Watts et al 2005

Absorptive wood/ cement £590/ m length/ 3m high - note 1 Watts et al 2005

Reflective transparent acrylic noise barrier

£600/ m length/ 3m high - note 1 Watts et al 2005

Note 1: HA 66/95 recommends that environmental noise barriers should be designed so that they require minimal maintenance other than cleaning or repair of damage for at least 20 years. A life of 25 years is often assumed for costing purposes. It is explained that in situ concrete or masonry walls require little or no maintenance during the desirable service life of 40 years. However transparent sections would need frequent cleaning and might need replacing after 10 or 15 years. The acoustic performance of absorptive barriers could be expected to be 10 to 20 years. TRL 046, 2005 explains that vegetative barriers with living willow are prone to problems of irrigation failure and attack by pests so a useful life may only be 10 years. However, barriers including ivy should prove more robust as they do not require irrigation after the plants are established.



Table 7.4 - Full Covers

Description Estimated price/ unit Cost year

Design Life

Reference Ref Year

Comment

Transparent cover over 2 lanes, acrylic

£10,350/ m length (max ht 8m)

- ?? Watts et al 2005

Transparent cover over 2 lanes, laminated glass

£15,870/ m length (max ht 8m)

- ?? Watts et al 2005

Table 7.5 - Tunnels


Design Life

Reference Ref Year

Comment

Cut and cover Single track tunnel

£15,000/ m 2009 120 years - - These costs are based on experience on a number of recent projects, however, the costs are affected by the width/length of tunnel required and prevailing conditions.

Significant maintenance costs are associated with M&E kit in tunnels which needs replacement at pre-determined intervals (whether life expired or not).

Cut and cover Twin track tunnel

£25,000/ m

Bored £10,000/ m 2009 120 years - -



Table 7.6 - Road surfaces


Design Life

Reference Ref Year

Comment

Hot Rolled Asphalt Base (210- 220mm thick)

£26 to £34/ m2 - 40 years SPON’S 133rd

edition, 2008

Assumes a total bound material thickness of 300mm.

Hot Rolled Asphalt Binder course (at least 50mm thick)

£10 to £16/ m2 - 20 years SPON’S 133rd

edition, 2008

Hot Rolled Asphalt Surface course (40-50mm thick)

£10/ m2 - 15 years SPON’S 133rd

edition, 2008

Includes the cost of planing the original road surface estimated at £2 per m2

Planing existing road surfaces £2/ m2

Stone Mastic Asphalt, Surface Course

£12/ m2 2009 12- 15

years LA Framework Does not include planning of original road

surface, or tack coats

Thin Surface Course (Cl.942) 10 years

Two-layer porous asphalt 30 EUR/ m2 - 1yr less

than ordinary pavements due to open texture

SILENCE 2007 Quality of laying very important. Regular cleaning required. Once surface clogged too much, cleaning has no effect.

7.14 When using a quieter road surface as a noise control measure, this would often involve the installation of a Stone Mastic Asphalt surface course. The existing road surface would be planed off first, particularly where there are headroom restrictions. Different road surfaces have different drainage requirements, and this would need to be considered when selecting such a noise control measure.



Table 7.7 - Speed Limit


Design Life

Reference Ref Year

Comment

20 mph speed limit sign

£1,300 to £3,000 2006 20 years LA standards - Traffic Signs Regulations and General Directions

The range includes for a pair of signs with an allowance for the signs to be illuminated, however, it does not include for the cost of orders to be drafted, advertised and implemented. It also does not include for repeater signs, as these costs depend on the length of the order. There is also no allowance for Vehicle Activated Signs. 20mph speed limits require physical measures to enforce the speed limit, these are also not included within these costs.

Sign materials are guaranteed for 10 years but last considerably longer. Lighting is likely to need replacing after about 5 to 10 years depending upon the units used and the availability of spares.

Accident statistics sign

£200 to £1,000 This varies depending on the size of the sign, which depends on the amount of information required to be given and the speed of traffic travelling on the road.

Sign materials are guaranteed for 10 years but last considerably longer. By their nature, the sign will probably need updating quarterly so that the information is relevant.

Speed Cameras

£28,000/ unit 2009 5 years Campaign for better transport

2009 The provision is subject to meeting certain safety criteria and therefore the use of these may be limited. The costs do not take into account any processing of fines or maintenance of the equipment. It is likely that cameras will be shared with other existing sites and therefore the cost of the housing, parking area and power only has been quoted. The housing may require early replacement due to cameras quickly becoming obsolete.

Costs do not include for provision of a safe area for maintenance vehicles – usually a grasscrete area with safety fence protection.



Table 7.8 - Humps and Cushions


Design Life

Reference Ref Year

Comment

Road humps, narrow cushions (width < 1700mm)

£600/ unit 2009 10 years Campaign for better transport

2009 These costs are affected by the width and length of the measures proposed.

Design life should be based on the standard assessment period of 60 years for such measures. However, more frequent maintenance and sweeping may be required and, depending on the type of construction, it is likely that many features will need a like-for-like replacement within 5 to 10 years. The cost does not include traffic management.

Flat topped humps £2,000/ unit 2009 5 years Campaign for better transport

2009

Round topped humps £1,200/ unit 2009 5 years Campaign for better transport

2009

Speed cushions £600/ unit 2009 5 years Campaign for better transport

2009



Table 7.9 - Chicanes, road narrowing, gateways


Design Life

Reference Ref Year

Comment

Chicanes/ road narrowing/ gateways

£6,000/ unit 2009 10 years Campaign for better transport

2009 Design life should be based on the standard assessment period of 60 years for such measures. However, more frequent maintenance and sweeping may be required and, depending on the type of construction, it is likely that many features will need a like-for-like replacement within 5 to 10 years. The cost does not include traffic management.

White lining road to reduce the perceived carriageway width

£7.5/m2 2006 5 years LA standards - This depends on the width of the hatching proposed in the centre of the road. Minimum charges may apply if only a small amount of work is to be undertaken. Depending upon traffic flow, lines will need replacing within 3 to 5 years on a like-for-like basis. Minimum costs may apply to lines as it is uneconomic for the contractor to lay small amounts. The price does not include traffic management.

Traffic islands/ pedestrian refuge

£6,000 – 8,000/ unit 2006 10 years LA standards - Traffic islands will need illumination. It may be preferable to use low voltage supplies to reduce maintenance costs. The equipment on the islands is likely to require changing within 10 years as spares become obsolete. However, the design life used for assessing such measures is normally taken as 60 years.

Junction table £20,000/ unit 2006 10 years LA standards - Design life should be based on the standard assessment period of 60 years for such measures. However, more frequent maintenance and sweeping may be required and, depending on the type of construction, it is likely that many features will need a like-for-like replacement within 5 to 10 years. The cost does not include traffic management.



Table 7.10 - Smooth Driving


Design Life

Reference Ref Year

Comment

Junction design Mini- roundabout

£18,000/ unit 2006 30 years LA standards - Design life should be based on the standard assessment period of 60 years for such measures. However, more frequent maintenance and sweeping may be required and, depending on the type of construction, it is likely that many features will need a like-for-like replacement within 5 to 10 years. The cost does not include traffic management.

Junction design Lighting columns

£1500 to £2500/ column

2006 30 years LA standards - Design life may depend upon the type of column used. The costs do not include cabling or feeder pillars as this would vary depending upon the location and number of columns.

Junction design Signs

£150 to £2000/ unit

Road design and realignment

- - 60 years - - This depends on the location, amount of realignment and effect on Statutory Undertakers apparatus.

The standard assessment period for a road scheme is 60 years.

Calming green waves (setting up coordinated signalisation)

- - 10 years - - This depends on the traffic signal equipment already installed, including is compatibility with the use of SCOOT or MOVA. Incompatibility would require all equipment to be replaced.

Link MOVA is still in its infancy and therefore changes in technology will make most equipment redundant within 5 to 10 years.



Table 7.11 - Redesign/ reallocate road surface


Design Life

Reference Ref Year

Comment

Creating bus lanes £150/m 2006 30 years LA standards The costs exclude traffic orders, widening or changes to bus stops and assume that there is available existing highway and no drainage changes are required. The cost therefore only allows for white lining and associated signs. There will be a minimum cost of approximately £5,000. White lining and signing will require maintenance every 3 to 5 years.

Creating cycle lanes £150/m 2006 30 years LA standards Assumes it follows the alignment of the existing road and requires only minimal alteration to road side features.

Planting trees (to give impression of narrow road) Saplings not exceeding 3m

£21/ unit - 60 years SPON’S 133rd edition, 2008



Table 7.12 - Altering Traffic Flow and Composition


Design Life

Reference Ref Year

Comment

Setting up HGV bans

£9,000 2009 60 years Campaign for better transport

2009 This depends on the number of signs required (affected by number of access points) and the need for any physical works to restrict access.

A standard design assessment period of 60 years is suggested, but signs would need maintenance within 20 years. The price excludes advertising TRO’s or enforcement.

Permanent road closure

£6000/ Junction 2009 60 years Campaign for better transport

2009 The price excludes advertising of TRO’s or any costs associated with re routing or changing of other junctions to cater for the dispersed traffic.

Banning through traffic

300 EUR each - 60 years SILENCE 2007 A standard design assessment period of 60 years is suggested.

New bypass road

10.000,000 EUR/ km



Cost of Noise Control Measures for Rail Traffic Noise

7.15 The implications of and options for reducing rail generated noise by the provision of physical barriers or the control of rail speeds are considered below. The analysis identifies, in principle, the operating, safety, engineering and commercial issues and constraints. Commentary is included about probable costs of adopting noise limitation measures.

Track side noise barriers

7.16 The possible adoption of track side noise barriers has been considered and the likely effect upon rail operations. Low height (up to 1m high) and higher (up to 3m high) line side barriers have been reviewed.

Low height barriers

7.17 Low barriers would be similar in height to a station platform. It is assumed such barriers would need to be located close to the track (approximately 2m) to be effective. The normal space between rail lines is usually a minimum of about 2m and the cess alongside the track about 3m from the track. The distances between tracks will vary according to track layouts but are unlikely to be less than those quoted to allow for necessary rolling stock clearance.

7.18 Uninhibited access for rail staff to the track side and in between tracks is necessary for track, and signalling equipment maintenance as well as routine work such as drainage, ballasting and access to other line side equipment. Train operating staff may also need to walk on the track to reach signal post or line side telephone, or deal with train failures or incident disruption.

7.19 It is therefore essential for operating reasons and the safety of staff engaged on track work to have unimpeded access to all sections of the rail line and to easily reach positions of safety without restriction. This is vital where work on the track might be carried out whilst trains are continuing to operate.

7.20 Low height barriers are unlikely to affect signal sighting but would need to be positioned to allow access to signals, relay cabinets, point equipment and other line side cable and apparatus which might be located either to the side of tracks or in between tracks.

7.21 The provision of low height barriers would therefore need to consider:

• Any effect on driver view and safety sighting;

• Distance between tracks and width of the cess;

• Clearance from track and rolling stock of passing trains;

• Access to line side equipment, signals and overhead line equipment where applicable;

• Clearance from the electrified 3rd rail on appropriate route sections;

• Clearance from trains where high speed rolling stock tilt operation might be applicable;

• Track safety and unimpeded access and escape from track work sites for rail staff engaged on track maintenance or renewal.

7.22 The low height barriers would also need to be properly secured and maintained to ensure there was no possibility of barriers becoming loose or dislodged with the consequent risk to trains.

7.23 Except for very short sections, low height barriers erected close to the track are unlikely to be acceptable principally for reasons of track access and on track safety.

Cost

7.24 The cost of low height barriers would be defined by the cost of erection and ongoing costs of maintaining the barriers. There would also probably be an indirect increase in costs of rail



infrastructure maintenance because of the need to work round or remove and replace barriers for routine maintenance or renewal.

Larger Lineside Barriers

7.25 Such barriers have been assumed to be up to 3 m in height. These would, in effect, be nearly the height of rail vehicles above rail level.

7.26 In addition to the issues of track access and track safety encountered with low height barriers, high barriers would raise additional issues concerned with signal vision, overhead line safety and vulnerability to high winds affecting security of the structures.

7.27 If erected near the track within the rail boundary, either between the tracks or adjacent to the cess, such barriers could obscure train driver’s vision of signals, especially where there were curves on a route. The height of the barriers would also raise potential safety concerns on electrified routes where overhead electric power lines were present.

7.28 Barriers up to 3m high would also need to be strongly erected and secured to avoid the possibility of these become unstable or vulnerable to high winds. As rail corridors are in most cases relatively narrow with just sufficient space for the number of tracks required, and a cess on either side, it is probable that high barriers would in most cases need to be erected outside the railway boundary.

Costs

7.29 In addition to costs of erection and normal maintenance, high barriers would also probably require additional preventative maintenance to ensure they did not become unsafe due to weather conditions.

Level Crossings

7.30 Noise barriers in the vicinity of level crossings would require to be positioned to ensure there is no obstructed view for road users or rail operators. CCTV is often used in the operation and monitoring of crossings and barriers would need to be clear of such fittings.

Design and Approval

7.31 Any form of noise barrier proposal would be subject to stringent design and approval requirements from Network Rail, Rail Operators and the Office of Rail Regulations for Safety Approval. The railway is subject to its own bylaws, powers and obligations and any requirement to erect barriers would be subject to the legal requirements and consequences. It is probable the rail industry would, in addition to the cost of erection and maintenance, require indemnity from accident, injury or delay caused by the provision of noise barriers.

7.32 Following approval, the process for erection of barriers would require individual design for specific locations, and railway possessions with all traffic stopped to facilitate the actual work. In addition to the actual cost of erecting barriers and design work, possession and disruption costs would include planning and compensation to rail operators. An indication of costs is given below.

Speed Reductions

7.33 Imposed speed restrictions to reduce noise would have the effect of reducing line capacity over the routes or sections concerned, increasing overall journey times and a negative impact upon the competitive position and income for rail. The impact of speed reductions will depend upon the normal line speeds on the routes concerned and the extent of the reduction. The normal line speed on main passenger routes will vary from a minimum of 75 mph to a norm of 90-100 mph to a maximum of 125 mph or in some cases 140mph. Freight trains will usually operate up to a maximum speed of 75 mph. In considering reductions in speed for this analysis, it is assumed a speed limit is imposed over relatively short sections of line purely to reduce noise impact. There is no railway operation or technical requirement assumed.



Line capacity

7.34 Reducing speeds over short sections of route is likely to have the operations and timetable effect of reducing line capacity. Maximum line capacity is dictated not only by the signalling provision and rolling stock capability but also by the consistency of performance of trains over a route. Hence variable speeds between different types of trains, differing characteristics and variations in performance, will increase the clearance time between trains and increase the amount of time needed for a train to pass through a given section. Thus artificially reducing train speed would most likely have the effect, on some sections, of reducing line capacity and the number of trains which might be handled in a given time.

7.35 The overall and most serious impact, especially on the busiest rail routes, would be to potentially reduce the number of trains operated and reduce the amount of rail capacity, for both passengers and freight, which the rail industry is able to offer to balance road demand and congestion especially into and out of major cities at the busiest times. Longer journey times might also have a far reaching impact as timetable slots over long distance journeys would be affected by longer times over just one section of route.

Commercial Implications

7.36 Any reduction in line speeds leading to an increase in overall journey times would have a serious impact on rail revenues and the ability of rail to compete with domestic flights and the private car and long distance coaches. Apart from safety aspects, most railway engineering and rolling stock and track advances over the 180 year history of the railway in the UK has been directed at reducing journey times through faster trains, better track design and more flexible signalling. There are numerous instances where railway advances have improved its competitive position such as electrification, High Speed Trains and more recently, tilting trains and the high frequency timetable on the West Coast Main Line.

7.37 Artificially imposed speed restrictions would increase journey times and are likely to have a negative impact on the rail industry’s greatest selling point over its rivals; its speed and overall shorter journey time. Ultimately this would lead to a decline in use of the railway, higher central government funding or financial support and a reduction in rail services. This would be in direct contrast to successive government’s promotion of rail passenger and freight transport as more sustainable and environmentally beneficial.

Delay Costs

7.38 As a guide to the commercial costs of reducing speeds, delay costs are assessed between train operating companies and Network Rail. Delay costs form part of a contract between operators and Network Rail and will vary significantly according to the intensity of service, travel demand and the time of day. As an example, delay costs to a long distance passenger train might typically be taken as £100 per minute. Thus, for a reduction in speed which increases a journey time by 5 minutes for an hourly passenger service in each direction (12 trains per day per direction), the cost penalty might be £12,000 per day or over £4million per operator per year.

7.39 Delay cost on heavily used passenger routes into main cities during peak hours might be significantly more whilst rural branch lines would be much less.

Noise Mitigation - Summary of Rail Costs

7.40 These costs are a broad high level estimate of the scale of cost likely to arise from possible measures taken to limit rail noise. The cost assessments have been calculated from Network Rail and rail industry unit costs where appropriate, using expert rail industry knowledge to assess, interpret and calculate likely scale of costs.



Rail Works

7.41 The following are National Rail unit costs identified in 2008.

Table 7.13 - Rail grinding

£ Cost per metre £ Cost per km

Straight track 8.21 8,210

Curved track 9.95 9,950

Sharp curve 13.27 13,270

Very sharp curve 26.73 26,730

Table 7.14 - Replacing Rail Pads, Clips, Nylons

£ Cost per metre

£ Cost per km

Replacing rail pads, clips, nylons (total cost) 130.00 130,000

Clips (component cost included within total) 26.00 26,000

Pads (component cost included within total) 7.00 7,000

Nylons (component cost included within total) 4.00 4,000

Table 7.15 - Relaying Cost

£ Cost per metre £ Cost per km

Remove and replace – sidings 450 450,000

Remove and replace - main line 600 600,000

Possession Cost Table 7.16 - Costs associated with possessions

Cost - £

Minimum cost of taking a single possession 1,500

Electrical Isolation 1,700

Speed Reductions

7.42 Artificial speed reductions, based on 5 minute delay on a main passenger route are estimated as £4 million per year per train operator using the route.

Cost of Barrier Provision

7.43 On the basis of rail values, the cost of erecting 3m barriers near the track within railway property is estimated as follows. These costs do not include allowance for land acquisition, surveys or planning approvals.



Table 7.17 - Cost of physical work to erect 3m high barrier. Average cost taken as £350 per metre.

£ Cost per km

Barrier works 350,000

Network Rail planning and approval and possession cost 35,000

Design consultancy & professional fees 42,000

TOC compensation and disruption costs 35,000

Risk/contingency 35,000

Total cost of barrier provision per km 497,000

Rolling Stock Maintenance

• Wheel Turning £250 per axle.

Costs of Building Envelope Improvements

7.44 There is limited data available to determine costs for building envelope improvement measures, and there is a high element of uncertainty in providing these costs as the actual work required would vary from building to building.

7.45 This measure is similar to the provision of noise insulation, under the Noise Insulation Regulations 1975 (as amended)32. Limited data from projects where this has been required shows total costs between approximately £2000 and £5000 per dwelling over recent years, from a small number of projects requiring one or two properties to be treated.

7.46 The measures would require the provision of an alternative form of ventilation, and these can be purchased for costs between approximately £50 and £500 for a single room unit, depending on the type. Installation costs would be in addition to the purchase costs.

7.47 Costs for windows would depend on the type of solution proposed, which may either be to replace existing windows with newer ones or by the addition of additional secondary glazing in conjunction with the existing windows. New double glazed windows may cost up to £500 per window, depending on the glazing specification.

7.48 In addition, there may be a requirement to install blinds, to provide ventilation for gas cookers if treating an open plan living area, and to block off existing ventilators.

7.49 The cost data identified relates to two storey houses where living and sleeping rooms have been treated. Should the measure be required in flats or apartments on the upper storeys of taller buildings, then installation costs are likely to be significantly higher than for two storey houses. Costs for this have not been obtainable.

7.50 Overall, the cost per dwelling would depend on the number of rooms and windows to be treated, and the acoustic specification of the measure being considered.

Chapter Summary

7.51 In order to assist the costing of noise remediation measures, this chapter provided indicative costs for various components of noise remediation measures. The costs are typical average values based on past project experience, market research and information available in the literature. The actual costs would depend on a number of site specific factors, particularly quantities required and the size and type of project, and will vary slightly between regions and with prevailing economic circumstances.



8. Valuing Changes in Noise

8.1 In order to compare the costs of noise control measures with the corresponding reductions in noise it is necessary to establish a monetary value for a change in noise. This allows both the costs and benefits to both be expressed in monetary terms. Appendix C describes different valuation approaches and methods for noise.

8.2 The main research to date on valuing the monetary consequences of noise impacts has focused on annoyance effects in a residential context. However, in recent years there has been a desire to better understand and value other more serious health effects of noise.

8.3 This chapter investigates:

• Value of noise annoyance in the context of residential dwellings;

• Consideration of time spent indoors and outdoors;

• Value of other noise-sensitive receptors;

• Health effects and issues surrounding their valuation;

• UK practices on noise valuation.

Noise Annoyance at Residential Dwellings

8.4 An overview of studies on external costs of noise was produced in an EC Green Paper1. It was found that the estimated costs of noise pollution in member countries varied between 0.2% and 2% of GDP. It was observed that studies based on the avoidance cost approach gave low values for noise costs (below 0.1% of GDP), while studies using the willingness to pay approach gave higher values. The different valuation methods are described in Appendix C. All the studies on ‘willingness to pay’ had been carried out in countries with a high per capita income. As willingness to pay depends on the ability to pay, noise would probably not be valued so high in less rich countries.

8.5 A review of the literature on noise valuation47 identified a wide range of ‘damage estimates’ in different forms of measurement. The range of results produced were summarised as follows:

• £15 - £30 per decibel per household per year (covering a total of 4 studies)

• 0.08-2.30% change in property price per decibel (covering a total of 43 studies)

• 0.02-2.27% GDP (covering a total of 15 studies).

8.6 It is common for different studies to make quite different estimates of the costs associated with noise. This can be due to methodological and sampling differences. Other reasons could be different assumptions about baseline noise levels (e.g. using different values between 30 and 65 dB(A) as a zero nuisance baseline) or use of different time periods to identify average noise levels.

8.7 The EU working group (WG) on Health and Socio-Economic Aspects recommended the (interim) use of the median value change in noise perceived by households of 25 Euro per dB (Lden), per household per year for road transport48. The validity range of this interim value is stated to be between 50/55 Lden and 70/75 Lden. The WG assumed a constant money value for a 1 dB (Lden) change in noise across the range of noise levels regardless of the initial (base) level of noise.

8.8 As part of the HEATCO project, a stated preference survey was carried out in six European countries to establish the willingness to pay values for road and rail noise reductions49. The results showed that there was little difference in willingness to pay values for annoyed, very



annoyed and extremely annoyed for both road and rail noise. The pooled results gave a value of 85 Euros and 59 Euros per annoyed person per year for these three categories to eliminate road and rail noise annoyance respectively.

8.9 A more recent review of how noise is monetised in European countries was carried out by Nijland and van Wee50. The study showed that noise is valued mainly by western and northern European countries. It is generally noise annoyance in a residential context that is valued for road traffic noise with slightly fewer countries valuing rail noise.

8.10 Current UK practices are described later in this chapter in further detail.

Valuation of Changes in Internal Levels

8.11 The noise valuation methods focused on residential properties do not typically distinguish between the internal environment of a residential property and external noise levels in gardens.

8.12 The strategic noise maps show external noise levels, and the assessment of environmental noise in the UK is based on the noise levels “just outside” properties, usually 1m in front of the building facade. The majority of the analysis of environmental noise at peoples’ homes develops relationships between these external noise levels and peoples’ perceptions of noise when they are at home, irrespective of if they spend their time at home indoors or using any outdoor spaces.

8.13 The noise levels within the properties would typically be lower than the noise levels outside those properties because the fabric of the building attenuates noise. The actual difference between indoor and outdoor noise depends on the fabric of the building, particularly doors and windows. Indoor noise levels would be lower when windows and doors are closed compared with when they are open.

8.14 When noise control measures are being considered that reduce the noise at its source, such as a quieter road surface, or the introduction of an obstruction to the noise propagation path, such as a noise barrier, then the noise levels that are just outside properties can be shown to drop. This reduction in noise is assigned to the entire property, and can be shown to apply to both indoor levels and those in any outdoor spaces.

8.15 If a noise control measure is proposed which improves the acoustic performance of the building envelope, then this measure would have no effect on the noise levels just outside the property. The benefits can only be assigned to the indoor spaces within the property.

8.16 Currently there are no methods available to calculate the monetary value of measures which improve internal noise levels only.

Other Noise-Sensitive Receptors

8.17 Monetary values of decibel changes based on house prices would not be applicable to community resources such as hospitals, schools, churches and public buildings or amenity spaces such as parks, footpaths and public amenity spaces. These different receptor types will have different noise ranges and cut-offs to which different monetary values are likely to be assigned.

8.18 Using a willingness to pay (WTP) approach of visitors to enjoy undisturbed nature, a number of studies51, 52, 53 assumed that noise damage in nature areas and noise abatement zones increases linearly from 0 Euro/m2 at and below 35 dB up to 0.3 Euro/m2 at and above 55 dB.

8.19 These values may be more applicable to the preservation of quiet areas, which is outside the scope of the current project. The amenity spaces considered as part of noise management areas would, by definition, be exposed to relatively high noise levels.

Health Effects

8.20 A review of practices in project appraisals in Europe54 identified that Denmark, France, Lithuania, Poland and Switzerland included health related costs related to noise with a money value. It was



found that Lithuania and Switzerland related health related costs on a dose-response assessment based on exposure. Denmark, France and Poland used alternative methods of assessing health- related costs of noise (other than annoyance).

8.21 The review identified that the methodology used in Lithuania was based on ‘hedonic pricing’ (see Appendix C) however the country report for Lithuania did not provide further details on this.

8.22 The country report for Switzerland explains that ‘stated preference/ contingent valuation’ have been used to value health-related noise impacts as well as other methods such as ‘net production losses’ and ‘medical treatment costs’. The approach was reported to be based on a then unpublished study which showed that noise is related to ischemic heart diseases and to hypertension related diseases, which both lead to premature deaths (measured in years of life lost) and hospital treatment. In Switzerland health costs are equivalent to one seventh of the costs of noise annoyance (measured by hedonic pricing).

8.23 Denmark and France value the health effects of noise, but in a very simplified manner. Denmark assumes the health effects are 50% of the annoyance costs. In France, a correction coefficient is applied to the unit cost of decibel to take the long term effects of noise on health into account. In recognition of the health effects, a 30% increase is applied to ‘annoyance’ costs for noise levels higher than 70 dB LAeq during the day and 65 dB LAeq during the night.

8.24 The WHO is currently working on quantifying the burden of disease from environmental noise including: cardiovascular disease, sleep disturbance and annoyance, hearing loss and tinnitus, and cognitive impairment. The technical reports published so far55 56provide a review of practice in the EU where noise valuation is based on health based indicators.

8.25 Noise valuations are typically based on dose-effect relationships. For many years dose-effect relationships for health based effects of noise other than annoyance have not been available. A recent Defra study57 undertook a two stage literature review of the existing evidence on the links between noise and health.

8.26 Phase 1 of the study identified that statistical associations had been observed between noise and several health effects. Six key health effects were considered namely: annoyance; mental health; cardiovascular effects; sleep disturbances; cognitive development; and hearing impairment. For each of these effects, excluding mental health, sufficient evidence was identified to suggest a link between noise and the adverse health effect and provided some evidence on which a dose- response relationship might be estimated.

8.27 Phase 2 considered cardiovascular effects, sleep disturbance and hypertension in further detail. A number of robust assessments were identified which linked increased occurrence of acute myocardial infarction and other cardiovascular effects in populations resident in areas with higher environmental noise sound levels. Because of a number of technical uncertainties, the report concluded that noise management decisions informed by cost benefit analysis based on the European dose-response relationships might not have the expected effects.

8.28 It was identified that the link between noise and transient sleep disturbance was a well developed area with statistically robust data and dose-response relationships. However there was no consensus on any single dose-response relationship which could be used to inform cost benefit analysis. In addition, no quantitative link has yet been established between acute or transient sleep disturbance caused by noise and any long term adverse health effects.

8.29 Although strong evidence was found to link noise and hypertension, there wasn’t sufficiently advanced evidence to support a fully quantitative assessment. It was recommended that hypertension effects can only be considered qualitatively when developing environmental noise management policies.

8.30 The work resulted in an outline framework which could enable potential benefits of road traffic noise reductions to be assessed as an economic value in terms of DALYs (Disability Adjusted Life Years). In a previous study30, the value of a life year was assumed to be 78,000 Euro.



Annoyance versus Health Effects

8.31 The ‘annoyance’ and ‘health-effects’ arising from noise may not be entirely separate. It may not be appropriate to assess the potential benefits of a noise control project against both change in house prices and improvement in DALYs, and simply sum the two together. In theory, the differences between the two effects are not mutually exclusive and they should not be summed.

8.32 Economists will often assume that people are rationale and perfectly well informed. An implication of this assumption is that when people purchase houses that are exposed to a high level of noise they will do so in the knowledge that it will be annoying (affecting amenity) and also in the knowledge that it will affect their health (both influencing quality and quantity of life). If this assumption holds true then the price people pay for their house, and by extension the valuation derived using hedonic property pricing, will include all these consequences of noise. In these circumstances, to include a separate financial valuation of health effects would be to double count. Therefore these two effects, in theory, would not be additive.

8.33 However, in practice, it is likely that people may be more aware of noise in terms of ‘annoyance’ but not in terms of the ‘health consequences’. In other words, the assumption of complete knowledge may not hold true.

8.34 In order to establish whether the measurement of the two effects is additive there would be a need to know whether the people whose house prices were included in various valuation studies were aware of the potential health effects of noise.

8.35 In addition, it is possible that the ‘annoyance’ effects may already capture some of the ‘health effects’ or vice versa.

Approaches in the UK

8.36 A number of current practices in the UK which identified the value of noise reductions are described below.

Hansard Criteria for Road Traffic Noise Hotspots

8.37 In 1999 the UK Highways Agency produced a report setting out criteria for the definition of existing road traffic noise hotpots in the UK and how noise control measures should be assessed and applied to reduce the noise levels in the hotspot area.

8.38 The aim of the programme is to identify the areas worst affected by existing road traffic noise and provide noise control. The roads where noise reduction is considered will have met the ‘Hansard’ criteria, i.e. noise levels immediately adjacent to the road (4m from the edge of the running carriageway) are in excess of 80 dB LA10,18h or are at least 3dB higher than predicted in the design year.

8.39 The assessment for road that meet the criteria is firstly carried out by assessing the number of people annoyed by road traffic noise in an area and the severity of annoyance. Then, possible noise control measures, such as road resurfacing and barrier installation, are assessed to determine the level of noise reduction possible at the receiver’s properties. If practical and cost effective noise control can provide a reasonable noise improvement for the majority of people severely annoyed, the cost can then be compared against the notional cost of providing sound insulation at the same properties.

8.40 The value of the noise reduction (cost per decibel) can be calculated for each assessment using the noise control measures costs and the predicted noise level reduction that will be achieved.

Birmingham Noise Valuation Project

8.41 This project applied hedonic pricing techniques to data collected from the City of Birmingham property market and examined differences in property prices to determine how much households



are willing to pay to avoid changes in their exposure to noise pollution58. The values estimated by this project have been based on a large and state-of-the-art dataset and advanced economical modelling.

8.42 The study resulted in a range of cost values for a noise change of 1 dB at different noise exposure levels. The noise levels are expressed in dB LAeq. The mean value for road traffic noise was £31.49 per annum for a 1dB reduction from a 56dB baseline and £88.76 per annum for the same change from an 80dB baseline.

Department for Transport Guidance on Noise Valuation

8.43 In 2006 the UK Department of Transport issued a new guidance as part of TAG which monetised the noise impact of road and rail noise. The TAG advice is presented in the context of considering overall impacts of infrastructure projects, but in principle can equally be applied to any change or project which would result in a change in road traffic or railway noise. The guidance cannot be used to determine the cost or value of current noise problems along existing sections of road or railway.

8.44 The noise valuation advice in TAG guidance is based on a research study aimed at putting a monetary value on impact of noise59. The assessment is based on the effect of noise on house prices and involves calculating the present value of households’ willingness to pay to avoid transport related noise over the whole of the appraisal period.

8.45 The findings of this study have been incorporated into the latest revision of Transport Analysis Guidance’s (TAG) Noise Sub-objective 3.3.2 and resulted in supplementary guidance on noise valuation60.

8.46 The noise valuation uses noise levels measured in the units LAeq,18hr, and guidance is provided to convert the LA10, 18hr from road traffic noise assessments. The noise values reflect the average UK values and are on the basis of per person affected. The value for noise starts at a value of £8.40 per annum for a 1dB reduction from a 45dB baseline and goes up to a value of £98.0 per annum for the same change from an 80dB baseline. These prices are for 2002, and the guidance provides a method for determining the equivalent values in other years. An example is given at the end of this chapter.

8.47 The process involves working out the benefits over the life of a scheme (i.e. the Present Value Benefits for transport related noise). It takes into account the expected growth in noise value over time as well as discounting using standard discount rates. DfT has provided a web based spreadsheet for undertaking the noise valuation calculations.

8.48 According to DfT’s Supplementary Guidance on TAG60, there are differences in the ‘Gross Disposable Household Income’ (GDHI) values at local level within the UK. The use of a single average monetary figure for noise throughout the whole UK may not always be appropriate in valuing the noise impacts. Where desirable, these local GDHI values could be used in the valuation of ‘benefits’ as part of the cost-benefit analysis.

8.49 Research undertaken by the DfT and described in the TAG documentation suggests a positive willingness to pay to avoid transport related noise down to 45 dB LAeq,18hr. Below this value, the monetary values people placed on noise could not be shown to be different from zero at a 95% confidence level. The value of noise reduction below this cut-off has been assumed to be zero.

8.50 Similarly the research did not provide evidence on values of the impact of noise above 81 dB LAeq

and the value placed on a decibel change in noise above this has been assumed to remain constant. It is expected that the cases where the noise levels at residential properties are higher than 81 dB would be rare.

8.51 The data on the influence of railway noise on property prices did not provide sufficient evidence to make a distinction between monetary values for road and rail sources.



8.52 The design and installation of noise control measures would give rise to changes in noise levels,

and it is therefore considered that the valuation methodology described in TAG would be applicable to a cost and benefit analysis of such remediation measures.

Attitudes to Noise from Aviation Sources in England

8.53 A recent study on behalf of Department for Transport dated 200761 examined hypothetical willingness to pay in respect of nuisance from aircraft noise, in relation to other elements, on the basis of stated preference (SP) survey evidence.

8.54 One of the findings of the study was that despite the internal consistency of the data, the implied valuations from the SP were much higher than may be considered plausible, when translated into a “per dB” value. The implied willingness to pay to remove all aircraft noise was £3.80 - £11.50 per annum per dB reduction in LAeq for respondents, depending upon household income level.

8.55 Overall, the conclusions were that the valuations from either method were not considered to be safe, and it would probably be necessary to rely on sources based on Hedonic Pricing.

Practical Considerations

8.56 For the purposes of this project, it is appropriate to use the TAG noise values for residential properties, and for both road and rail noise sources. TAG requires that the noise levels are expressed in LAeq,18hr, and provides the conversion LAeq, 18hr = LA10, 18hr – 2.5 dB(A) for road traffic noise assessments.

8.57 TAG valuation method would be appropriate because it:

• Is based on the relatively well established relationship of ‘annoyance-willingness-to-pay – house prices’.

• Recognises that people exposed to relatively high initial noise levels would appreciate a given reduction more compared with those who are in lower noise areas, allowing more pressing cases of noise to be given priority in policy terms.

• Enables most high noise levels to be assessed by providing a upper noise limit of 81 dB LAeq,18hr for valuation studies.

• Uses noise index of dB LAeq,18hr as the basis of calculations, which can be aligned with the outputs of strategic noise maps, calculated directly using appropriate methods or derived from dB LA10,18hr by using accepted conversion methods.

• Is applicable to both road and rail sources since the data on the influence of railway noise on property prices did not provide sufficient evidence to make a distinction between monetary values.

• Uses the unit of ‘currency per decibel dB (A-weighted) per household per year’ which is a convenient unit for use as part of strategic noise maps and for relating to population data.

• Allows the standard values of a 1 dB change to be related to local situations, if desired, by using regional values for Gross Domestic Household Income (GDHI) index.

8.58 For noise valuation, it is useful to account for noise changes to the nearest decibel. However it would be necessary to consider the ‘perceived’ benefits of noise reductions as part of noise control measures design, as described in chapter 4.

8.59 The TAG noise valuation could be supplemented by an assessment of potential health benefits of the noise reductions as described in a recent Defra report57. This study identified the following:

• Robust dose-response relationships exist for cardiovascular health effects of noise and these could be related to DALYs. However the ‘time of residence’ has a bearing on the risk of developing cardiovascular disease and this would need to be factored into the calculations.



• DALYs can be converted to monetary values per year using appropriate monetary figures. These values would need to be integrated over the appropriate assessment period.

• The underlying dose-effect curves were based on studies which only involved road traffic noise.

8.60 As explained above, a ‘health-effect’ assessment of noise changes in addition to the ‘annoyance’ effect could result in some degree of double counting.

Non-residential Locations

8.61 There are currently no standard valuation methodologies in the UK for non-residential locations such as private gardens, recreational land, public spaces, workplaces, schools and hospitals. Existing methods are not aimed specifically at the UK, and this presents an opportunity for further research to verify these methods or to identify more robust noise values.

Valuation and Discounting Example

8.62 The guidance in TAG explains in detail the steps required to value a change in noise, and the various datasets required are presented in Appendix C.

Noise Benefits Calculation

8.63 An example valuation calculation is given to illustrate the main steps.

8.64 Step 1: Work out the willingness to pay for the change in noise in the opening year. Let us suppose that as the result of a noise control measure, the noise level outside a property drops from 71dB LAeq to 67dB LAeq, a reduction of 4dB.

8.65 The monetary value of this change in noise can be calculated, in terms of 2002 prices from the data in Appendix C, Table C1.

Table 8.1 – Value of benefits in opening year

Change in Noise in opening year £ per household per dB change

71dB to 70dB £74.30

70dB to 69dB £71.70

69dB to 68dB £69.00

68dB to 67dB £66.40

Total – 71dB to 67dB £281.40

8.66 Step 2: Repeat this for any other future assessment years being considered. For this example, we suppose that an assessment has been carried out 10 years after the measure, which shows that traffic growth has given rise to a 1dB increase which would have occurred whether the scheme was in place or not. Therefore, in the 10th year, the assessment of the measure would show a reduction of noise from 72dB LAeq to 68dB LAeq, a reduction of 4dB.

8.67 The monetary value of this change in noise can be calculated, in terms of 2002 prices from the data in Appendix C, Table C1.

Table 8.2 – Value of benefits in year 10

Change in Noise in year 10 £ per household per dB change

72dB to 71dB £76.90

71dB to 70dB £74.30



70dB to 69dB £71.70

69dB to 68dB £69.00

Total – 71dB to 67dB £291.90

8.68 Step 3: Use linear interpolation to value changes in noise between the assessment years being considered.

Table 8.3 – Value of benefit in intervening years

Year Benefit

0 £281.40

1 £282.45

2 £283.50

3 £284.55

4 £285.60

5 £286.65

6 £287.70

7 £288.75

8 £289.80

9 £290.85

10 £291.90

8.69 Step 4: Assume that noise levels do not change after the last assessment year.

Table 8.4 – Value of benefits in future years

Year Benefit

10 £291.90

11 £291.90

12 £291.90

…

58 £291.90

59 £291.90

60 £291.90

8.70 This gives the value of the change in noise over the appraisal period, in 2002 prices.

8.71 Step 5: Identify growth factors for the actual years being considered. Let us suppose that the scheme is implemented in 2011. The data for growth factors is given in Appendix C, Table C2. The growth factor for each year is the multiplication of all growth factors for all years between 2002 and the year in question, so the factor for 2011 would be a multiplication of the factors for the period 2002 through to 2011. Table 8.5 illustrates the results.



Table 8.5 – Growth Factors for benefits from 2002 prices

Year Year Benefit Growth Factor

2011 0 £281.40 1.187064

2012 1 £282.45 1.205695

2013 2 £283.50 1.224619

2014 3 £284.55 1.243839

…

2019 8 £289.80 1.344562

2020 9 £290.85 1.365665

2021 10 £291.90 1.387099

2022 11 £291.90 1.40673

…

2070 59 £291.90 3.01586

2071 60 £291.90 3.067561

8.72 Step 6: Discount the benefits in line with the values in the Green Book. The data for discounting factors from the Green Book is also given in Appendix C, Table C3. No discount is applied in the first year of the assessment, but each subsequent year is discounted by the appropriate discount rate, so after 1 year the discount factor is 1 minus 3.5%, and after 2 years the discount factor is 1 minus 3.5% twice.

8.73 Overall, the benefits must be growthed and discounted, so the benefit in each year is multiplied by both the growth factor and the discount factor for that year. Table 8.6 illustrates the results.

Table 8.6 – Discounting benefits

Actual Year

Years from

opening

Benefit Growth Factor

Discount Rate

Discount Factor

Discounted Growthed

Benefit

2011 0 £281.40 1.187064 3.50% 1.00000 £334.04

2012 1 £282.45 1.205695 3.50% 0.96618 £329.03

2013 2 £283.50 1.224619 3.50% 0.93351 £324.10

2014 3 £284.55 1.243839 3.50% 0.90194 £319.23

…

2019 8 £289.80 1.344562 3.50% 0.75941 £295.91

2020 9 £290.85 1.365665 3.50% 0.73373 £291.44

2021 10 £291.90 1.387099 3.50% 0.70892 £287.04

2022 11 £291.90 1.40673 3.50% 0.68495 £281.26

…

2040 29 £291.90 1.849739 3.50% 0.36875 £199.10



Actual Year

Years from

opening

Benefit Growth Factor

Discount Rate

Discount Factor

Discounted Growthed

Benefit

2041 30 £291.90 1.881449 3.50% 0.35628 £195.67

2042 31 £291.90 1.913703 3.00% 0.34590 £193.22

2043 32 £291.90 1.946509 3.00% 0.33583 £190.81

…

2069 58 £291.90 2.965031 3.00% 0.15572 £134.78

2070 59 £291.90 3.01586 3.00% 0.15119 £133.09

2071 60 £291.90 3.067561 3.00% 0.14678 £131.43

8.74 Step 7: Sum the results over the appraisal period. The total over the 60 year appraisal period for this example is £12,916. This figure is the economic benefit for one household, and the process would need to be repeated for all of the other residential properties being considered.

Valuing costs of mitigation measures

8.75 For the costs associated with measures, the steps to identify the net present value the following steps are required.

8.76 Step 1: identify the costs of the noise control measure and identify the maintenance schedule. Let us suppose that a 200m long, 3m high timber barrier is being considered beside a road.

Table 8.7 - Costs of the noise control measure

Item Cost allowance Cost

Timber barrier (£210/m from Table 7.3) N/A £42,000

Highway Authority Approvals 10% £4,200

Design Costs 12% £5,040

Traffic management 20% £8,400

Protection 10% £4,200

Risk/Contingency 10% £4,200

Total Costs £68,040

8.77 Let us suppose that maintenance is required every 10 years at 10% of the supply costs, and that the barrier requires replacement every 20 years. The replacement barrier would not require planning approvals or design costs, but it has been assumed that traffic management and replacement barrier protection was required.

Table 8.8 - Costs of the maintenance activities

Item Cost allowance Cost

Maintenance Costs (Every 10 year) 10% £4,200

Replacement timber barrier (Every 20 years) N/A £42,000

Traffic management for replacement works 20% £8,400



Replacement protection (Every 20 years) 10% £4,200

Total Costs – Maintenance (Every 10 year) £4,200

Total Costs – Replacement (Every 20 years) £54,600

8.78 Step 2: Set out the costs of the noise control measure:

Table 8.9 - Costs of the maintenance programme

Year Activity Cost

0 New Barrier £68,040

10 Maintenance £4,200

20 Replacement £54,600


40 Replacement £54,600


8.79 Step 3: Discount the costs in line with the values in the Green Book. The data for discounting factors is given in Table C3.

Table 8.10 – Discounted maintenance costs

Year Activity Cost Discount factor

Discounted Cost

0 New Barrier £68,040 1.00000 £68,040

10 Maintenance £4,200 0.70892 £2,977

20 Replacement £54,600 0.50257 £27,440

30 Maintenance £4,200 0.35628 £1,496

40 Replacement £54,600 0.26510 £14,474

50 Maintenance £4,200 0.19726 £828

8.80 Step 4: Sum the discounted costs over the appraisal period to give the economic cost. The total economic cost of this noise control measure is £115,257. For this particular maintenance and replacement programme, the economic cost is seen to be approximately three times the initial cost of £42,000.

8.81 If the barrier were located away from the roadside, for example at the top of a cutting, then traffic management and protection costs would not be incurred, and the economic cost would be £92,984, or approximately double the initial cost, as shown in the following table:

Table 8.11 – Discounted alternative maintenance costs

Year Activity Cost Discount factor

Discounted Cost

0 New Barrier £55,440 1.00000 £55,440

10 Maintenance £4,200 0.70892 £2,977



20 Replacement £42,000 0.50257 £21,108

30 Maintenance £4,200 0.35628 £1,496

40 Replacement £42,000 0.26510 £11,134

50 Maintenance £4,200 0.19726 £828

8.82 It should be noted that the overall costs for barriers beside a railway line would be different. Maintenance and replacement activities may incur train operator disruption costs, and the economic cost in this situation would be approximately 2.5 times the initial cost.

8.83 A similar approach can be followed for the use of quieter surfacing. However, since roads need to be re-surfaced as part of routine maintenance, the cost of the measure is the difference between the cost of maintaining the existing road surface compared with the cost of maintaining the new road surface. Table 7.6 identifies that a Thin Wearing Course has a shorter design life than a Hot Rolled Asphalt surface, and therefore resurfacing would be required more frequently. The economic cost of this would be approximately equal to the cost of the initial cost, including planing the existing road surface.

Example Costs Comparison

8.84 With the two examples above it is possible to undertake a comparison of the costs and benefits. If we assume that the barrier is required at roadside, then the economic costs of the measure are £115k. The economic benefits for this measure were shown to be £13k for one property, and therefore, if the measure were providing the same benefits at more than 9 properties, and assuming that no other costs or benefits were incurred, then the benefits of the measure would outweigh the costs. This comparison provides the Net Present Value (NPV) of the measure, as shown in the following table.

Table 8.12 – Example Net Present Value

Measure provided at number of properties

Economic benefits from reduction in

noise

Economic cost of noise control

measure

Net Present Value

1 £12,916 £115,257 -£102,341

8 £103,328 £115,257 -£11,929

9 £116,244 £115,257 £987

10 £129,160 £115,257 £13,903

20 £258,320 £115,257 £143,063

Chapter Summary

8.85 This chapter has outlined the methods for valuing changes in noise by reference to published works, and current examples from the UK. It highlights that the majority of research is based on annoyance effects, although more recently, work is focussing on methods for valuing other impacts, primarily health effects. The main practical considerations which need to be taken into account when attempting to value changes in noise are highlighted.



9. Other Costs and Benefits

9.1 This project has focussed on the method for the assessment of noise levels from noise control measures, and the valuation and costs of those noise levels. In order to get a complete appraisal of a proposal, the assessment needs to include all other costs and benefits.

9.2 Measures designed to abate noise could have an impact on other policy objectives positively or negatively and to varying degrees. For example, a noise barrier could have an adverse impact on the visual amenity of an area. Depending on the location of the dwellings, the impacts could be worse at some locations compared with others.

9.3 These impacts may have monetary implications and should be taken into account within a cost- benefit analysis. It may not always be possible to evaluate all secondary effects in monetary terms, however, all effects should at least be identified.

9.4 This chapter of the report aims to:

• Identify relevant costs associated with noise control measures;

• Describe methods of costing these costs in the UK, where available;

• Identify what other assessments may be required.

Costs Associated With Noise Control Measures

9.5 Noise control measures comprising traffic calming methods and traffic management measures are likely to be implemented as part of a wider transport plan and serve a variety of purposes (safety, strategic transport routes, congestion, journey times, carbon emissions, other environmental benefits) as well as noise.

9.6 Noise control measures, such as noise barriers and acoustic insulation of building facades, are more likely to be mainly implemented for noise control reasons. There could be instances where photovoltaic barriers are used to generate electricity, or noise barriers include innovative surfaces to absorb pollutants from traffic or acoustic double glazing is utilised as thermal insulation as well.

9.7 The impacts of noise control measures on other policy objectives could be determined through a checklist of cost categories. There are a number of studies which investigated the costs in the transport sector. The projects entitled ‘Unification of accounts and marginal costs for Transport Efficiency’ UNITE (2003)62 and ‘Developing Harmonised European Approaches for Transport Costing and Project Assessment HEATCO’ (2005)54 are two examples.

9.8 The objective of the UNITE project was to support policy makers in setting charges for the use of transport infrastructure by the provision of appropriate methodologies and empirical evidence. A number of case studies covered the cost categories such as infrastructure costs, supplier operating costs, transport user costs and benefits, accident costs, and environmental costs.

9.9 The primary objective of HEATCO was the development of harmonised guidelines for project assessment and transport costing at an EU level. The costs were summarised under construction related costs, user benefits and vehicle operating costs, safety, environmental impacts, and indirect socio-economic effects.

9.10 Although these cost categories may not always be directly relevant to noise remediation measures, they would provide a consistent basis for ensuring all relevant factors are taken into account. The various cost categories highlighted in the UNITE and HEATCO projects can be summarised under infrastructure, user benefits, externalities and indirect socio-economic effects. The relevant sub-categories other than noise are summarised in Table 9.1 to Table 9.4, together with the current UK methods of assessing costs.



Table 9.1 – Infrastructure Costs

Cost Sub-category Description Cost assessment method

Construction Material/ labour/ energy Cost Benefit Analysis (CBA)

Land & property purchase CBA

Planning and mitigation CBA

Disruption from construction Delays caused during works CBA / Qualitative Assessment (QA)

Change in risks of accidents CBA / QA

Effects on neighbourhoods CBA / QA

System operation and maintenance

Operation (Signalling and traffic control)

CBA

Maintenance (Cleaning, minor repair, winter servicing)

CBA

Renewal (Road surfacing) CBA

Table 9.2 – User Costs and Benefits


Passenger transport time savings

Non-Work Trips Willingness To Pay (WTP)

Work Trips Stated Preference, Contingent Valuation, Revealed Valuation

User charges and revenues - Definitive rules constructed

Reliability, congestion and service quality

- CBA

Vehicle operating costs(VOC) Repair and maintenance Standard Method to calculate VOC

Depreciation of vehicles Standard Method to calculate VOC

Fuel and lubricants Standard Method to calculate VOC

Material costs Standard Method

Benefits to goods traffic Vehicle operating costs CBA

Crew wages (time and distance effects)

CBA



Table 9.3 - Externalities


Safety (saving accidents) Material damage CBA

Personal loss for casualties Cost Benefit Analysis Programme (COBA)

Costs to society (medical treatment, legal and court costs, emergency services, net production loss)

CBA

Air pollution (local/ regional) - Uses ExternE values - from Ecosense

Climate change - Unit value per ton of carbon emitted based on informal meta

Other environmental impacts Human health, materials, ecosystems, flora, fauna

Quantitative Measurement (QM)

Table 9.4 – Indirect socio-economic effects


Land use - Multi Criteria Analysis (MCA)

Economic development - MCA

Employment (short/ medium/ long term)

- MCA

Cohesion - MCA

Urbanisation - -

Network effects - CBA

Effects of state finances - CBA

Equity - MCA

9.11 The cost categories and assessment methods highlighted in this chapter would provide a useful checklist against which the applicability of various costs could be verified for noise remediation measures. For example, the costs of a noise barrier may need to reflect most elements of ‘infrastructure costs’ category and selected elements of ‘indirect socio-economic effects’ and ‘externalities’ categories. On the other hand, a new by-pass built as a means of minimising the noise impacts at a local community would need to consider all of the cost categories above.

9.12 Further details of methods of assessing costs and benefits of these are described below.

Costing Methods in the UK

9.13 In the UK, the cost benefit analysis is based on DfT/ TAG guidance. Transport Analysis Guidance (TAG) has been prepared by the DfT which allows projects involving changes to the road or



railway networks to be assessed, and is published on the DfT web site www.webtag.org.uk. The noise element of this work has been drawn on in the earlier chapters of this report to form the residential elements of the cost benefit analysis process. The TAG guidance provides methods of appraising the majority of elements for road and rail transport schemes. The key aim of a CBA is to account for and assess all the ways in which a project impacts on people. The results of appraisals are presented in an Appraisal Summary Table (AST), which provides a useful framework to ensure that the majority of potential impacts are considered.

Transport Assessment

9.14 Where a scheme would give rise to changes in the traffic along a road or railway, then these impacts would need to be assessed, both in the area where the measure is proposed and considering any re-routing or other changes to traffic elsewhere on the transport networks.

9.15 The Department of Transport provides guidance on the type and level of assessment required. Their guidance states that “a Transport Assessment (TA) is a comprehensive and systematic process that sets out transport issues relating to a proposed development. It identifies what measures will be taken to deal with the anticipated transport impacts of the scheme and to improve accessibility and safety for all modes of travel, particularly for alternatives to the car such as walking, cycling and public transport.”

9.16 The assessment should set the proposal in terms of these considerations:

• Encouraging environmental sustainability;

• Managing the existing network;

• Mitigating residual impacts.

9.17 The effect of the scheme should be considered the in terms of the Government's five objectives for transport as outlined in A New Deal for Transport and A New Deal for Trunk Roads White Papers:

• Environmental Objective (detailed below, and in TAG Unit 3.363);

• Safety Objective (TAG Unit 3.464);

• Economy Objective (TAG Unit 3.565);

• Accessibility Objective (TAG Unit 3.666);

• Integration Objective (TAG Unit 3.767).

9.18 It would be normal to undertake some modelling on the expected changes to the transport network, and TAG Unit 3.1.268 provides guidance on undertaking transport modelling.

9.19 All values of time and operating costs experienced by users and non users are derived from TAG Unit 3.5.669. The values presented in this Unit are appropriate for use in industry standard COBA, TUBA and QUADRO computer programs. Key impacts to be assessed and contained within this Unit include:

• Travel time;

• Vehicle operating costs;

• Accidents;

• Maintenance costs;

• Greenhouse gasses.

9.20 Matrices of traffic flows, distance and time; along with scheme capital costs including on-going costs and risk can be input into TUBA software to enable an assessment of the social costs and



benefits of the scheme. To ensure a complete assessment of impacts is undertaken the assessment from TUBA can be supplemented by the COBA programme to assess and monetise any accident benefits derived and by QUADRO to assess the total cost of any major road maintenance works made up of the direct works costs and user costs.

9.21 The main impacts are presented in an Appraisal Summary Table (AST)70. The AST incorporates qualitative and quantitative information, where the latter is expressed in monetary values. Key impacts to be monetised include: journey time/delay, noise, greenhouse gasses and accidents. A qualitative assessment is made for any impacts on landscape, townscape and heritage of historic resources.

9.22 The overall economic worth of a scheme option is summarised using the following two key measures; each of which compares the benefits of the option with its costs.

• The Net Present Value (NPV): The NPV is the discounted sum of all future benefits less the discounted sum of all future costs over the appraisal period - usually 60 years. Where there is no constraint on investment funds, there would be a strong case for taking forward all projects with a positive NPV.

• The Benefit/Cost Ratio (BCR): The BCR is given by the ratio: Net Present Value (NPV) + Present Value of Cost to Public Accounts divided by the Present Value of Cost to Public Accounts. The BCR is, therefore, a value for money measure, which indicates how much net benefit would be obtained in return for each unit of cost to public accounts. This is clearly relevant in the real world situation of limited funding available from public accounts.

9.23 The discounting process is described in paragraph 10.14, with an example in Chapter 8.

Sustainability Management

9.24 The management of sustainability issues are often associated with the 'operational phase' of a particular project. However, with considered planning and assembly of the relevant skills, a Sustainability Management System (SMS) can be developed to apply to the entire life-cycle of a project, incorporating: design, construction, operation and ultimately decommissioning.

Sustainability Management System

9.25 The SMS concept works on the basis that throughout the various stages of the project it will be possible to influence or control environmental and sustainability impacts. This is important, as issues which can be resolved at the design stage, will no longer necessarily apply during construction or operation.

9.26 The benefits of adopting project environmental and sustainability management systems include:

• The ability to undertake and demonstrate a consistent and holistic approach to the management of sustainability issues throughout the project life-cycle;

• The assurance of legal compliance, because the formal systems adopted for registering and managing legal requirements are passed between each stage of the project’s life-cycle;

• The effective management of social and environmental risks, because the adoption of a project SMS from inception will facilitate the identification of risks and liabilities which can be planned for, and mitigated, wherever possible.

Planning Phase

9.27 At the planning stage for each project, the responsible authority should identify and evaluate all environmental and sustainability requirements applicable to the project and assemble all necessary baseline environmental and social data/information for this purpose.



9.28 This will allow the project team to conduct a review of environmental and sustainability risks and

impacts well in advance of design and construction work taking place, enabling reliable planning and delivery of environmental and sustainability risk mitigation measures.

Design Phase

9.29 Throughout the design process, Environmental and Sustainability Specialist(s) will assess the impact of each design option against the baseline information to determine:

• Possible environmental and sustainability effects that can be eliminated or reduced;

• Any additional possible additional environmental and sustainability risks that may be created by the design option.

9.30 Once the design team has identified and ‘designed-out’ the identified environmental and sustainability effects as far as possible, they would identify any residual effects associated with the project which would then need to be managed.

9.31 Residual risks can be categorised as follows:

• High: Further mitigation required /significant residual risk;

• Low: Mitigation satisfactory;

• None: No residual risk.

9.32 Once the residual risks and impacts have been identified and evaluated for their significance, it will be possible to commence with the preparation of necessary operational controls of the procurement, construction and implementation phases.

Procurement Phase

9.33 Throughout the design and construction process, appropriate consideration of environmental and sustainability issues will be required to enable the suitable control of sub-contractors, suppliers and specification of product/materials. The SMS for the project will include the development of controls for materials suppliers during design and for contractors during construction.

Construction and Implementation Phases

9.34 The project team will develop the SMS to detail both the management and operational controls to be adopted during the construction and implementation activities associated with the physical development of the project.

9.35 The SMS will detail the practices to be adopted to ensure the successful delivery of the construction and implementation phases of the project in accordance with all applicable legislative, client and other applicable requirements in relation to environmental and sustainability performance.

Operational Phase

9.36 Once the construction and implementation phases are complete, appropriate consideration of residual environmental and sustainability issues will be required to inform the maintenance programme for the project. The SMS will detail the practices to be adopted to ensure that the measures are maintained in accordance with all applicable requirements in relation to environmental and sustainability performance, and to enable the suitable control of any sub- contractors and suppliers required.

Sustainability in the Context of Noise Mitigation Measures

Noise Barriers

9.37 During the design phase of noise barriers, the selection of the materials used to construct the noise barriers can have a significant impact on the sustainability of the project. The potential



range of materials available for noise barriers may be constrained by other requirements potentially including safety, visual appearance and acoustic performance.

9.38 The assessment of the sustainability should consider the following aspects of the barrier:

• Its life-expectancy;

• The expected maintenance routine;

• The location of its fabrication (on-site or off-site);

• The method of fabrication and erection.

9.39 Once materials have been selected for the barrier, these should be sourced locally where possible, and consideration given to using local labour for the installation.

Road Re-surfacing

9.40 The primary focus for road surfaces is safety, both in terms of skidding resistance and stopping distances. The acoustic properties of road surfaces are often at odds with the longevity of the surfaces, and from a sustainability perspective, the aim is to have a surface with the longest life which meets the safety and acoustic requirements.

9.41 In addition, the assessment of the sustainability should consider the re-use and recycling of any existing surfacing materials removed.

9.42 Once materials have been selected, these should be sourced locally where possible, and consideration given to using local labour for the installation.

Rail Maintenance

9.43 This type of measure is likely to have been assessed by the track or vehicle owner/operator from a sustainability perspective. Attention should be paid to re-use or recycling of any materials replaced.

Building Treatments

9.44 This measure would typically involve the installation of secondary or replacement windows and/or doors, and the provision of ventilation. The selection of materials can have a significant impact on the sustainability of the project. The potential range of materials available may be constrained by other requirements potentially including security, thermal and ventilation requirements.

9.45 The assessment of the sustainability should consider the following aspects, particularly if ventilation is provided mechanically:

• Life-expectancy;

• Maintenance requirements;

• Energy requirements for ventilation systems.

9.46 Once materials have been selected for the treatments, these should be sourced locally where possible, and consideration given to using local labour for the installation and the re-use or recycling of any materials removed.

Road Traffic Management

9.47 This type of measure is likely to restrict or re-direct traffic in at least one area, and would therefore require the installation of signing, road markings or other physical installations.

9.48 In the design phase, the method of controlling traffic should be assessed from a sustainability perspective in terms of materials, energy usage and maintenance requirements.



9.49 Once materials have been selected for the measure, these should be sourced locally where

possible, and consideration given to using local labour for the installation. Materials removed should be re-used or recycled where possible.

Environmental Aspects

9.50 Each type of noise control measure considered may require an assessment of other environmental impacts. The following sections describe each of the main noise control measure types considered, and an overview of which assessments may be required. It would be the responsibility of the assessor to ensure that all appropriate assessments had been considered.

9.51 At the time of writing, none of the subjects given below have their impacts monetised, and the majority of impacts are measured on a seven point scale.

9.52 Guidance for assessing and appraising environmental impacts can be found in TAG unit 3.3, DMRB Volume 11, and in the Guide to Transport and Works Act Procedures. In all cases, the assessment of environmental impacts should be undertaken in the context of the Environmental Impact Assessment regulations.

9.53 Any assessments should bear in mind the potential for additional impacts from the construction of the noise control measure, particularly if extensive vegetation clearance is required. These issues are not considered in this report.

Noise Barriers

9.54 Air Quality: Assessment unlikely

9.55 Ecology: An assessment is required for all barrier works to comply with protected species legislation. Impacts are expected to be more significant with longer lengths of barriers.

9.56 Cultural Heritage: An assessment would be required as the construction of barriers could have a direct impact on buried archaeological remains and potential indirect impact on the setting of sensitive buildings and features (i.e. Listed Buildings, Conservation Areas, Scheduled Monuments and other non-designated remains).

9.57 Landscape and Visual Effects: An assessment is required, particularly where barriers are over 2m in height. Barriers have the potential to become a significant visual intrusion in the landscape both in their own right and in respect of obscuring views out from areas.

9.58 Community Effects: An assessment is required because of the potential for noise barriers to be seen as forming a physical/visual barrier that adversely impacts on the community. Consideration should be given to community severance in respect of closure or diversion of rights of way.

9.59 Flood Risk and Drainage: An assessment would be required to consider any loss of floodplain and runoff volumes. Effects may be significant in flood zones where ground conditions are impermeable.

9.60 Water Quality: Assessment required, but effects not likely to be significant.

9.61 Geology and Soils: Assessment required, but effects not likely to be significant.

Road Re-surfacing

9.62 Air Quality: Although unlikely, an assessment may be required in respect of dust.

9.63 Ecology: Assessment unlikely

9.64 Cultural Heritage: An assessment may be required when the re-surfacing works involve the removal of the existing road surface as this has the potential to impact on buried archaeological remains

9.65 Landscape and Visual Effects: Assessment unlikely



9.66 Community Effects: Assessment unlikely

9.67 Flood Risk and Drainage: An assessment would be required to consider any loss of floodplain. Effects may be significant in flood zones where ground conditions are impermeable.

9.68 Water Quality: Assessment required, but effects not likely to be significant.

9.69 Geology and Soils: Assessment unlikely

Rail Maintenance – Track Re-grinding

9.70 Air Quality: Although unlikely, an assessment may be required in respect of raised levels of PM10.


9.72 Cultural Heritage: Assessment unlikely.


9.74 Community Effects: Assessment unlikely

9.75 Flood Risk and Drainage: Assessment unlikely

9.76 Water Quality: Assessment unlikely


Building Treatments

9.78 Air Quality: Assessment unlikely


9.80 Cultural Heritage: An assessment should include impact on the fabric and character of sensitive buildings (Listed Buildings and those within Conservation Areas)

9.81 Landscape and Visual Effects: Assessment covered by planning process

9.82 Community Effects: Assessment covered by planning process





9.86 Air Quality: An assessment would be required as this type of measure may change concentrations of pollutants at properties and in comparison to air quality standards.


9.88 Cultural Heritage: An assessment should consider the possibility of diverting traffic to pass through Conservation Areas or near Listed Buildings.


9.90 Community Effects: Assessment may be required, Effects are likely to be greatest if the measures decrease speeds on rural or suburban single carriageways.






Planning and Building Control

Planning

9.94 Planning Legislation and Regulation is not uniform across the whole of the UK. Although there are areas of commonality, the planning system in Scotland and Northern Ireland in particular can be significantly different from that operated in England and Wales. A review of Planning legislation, policy and the planning process is given in Appendix G.

9.95 It should be noted that some of the noise control measures outlined in this report fall outside the scope of planning control i.e. planning permission is not required. In such cases the normal best practice would be to inform the local planning authority about the proposal/works prior to them being undertaken.

9.96 Whether a proposal /works falls within the scope of planning control (for which planning permission, or ‘prior written approval’ from the local planning authority is required prior to the commencement of the works) is broadly determined by the following considerations:

• If the proposal/works fall within the definition of ‘Development’ (under the Town & Country Planning Act 199071) (as amended);

• If the proposal/works are considered ‘Permitted Development’ (under the Town & Country [General Permitted Development] Order 199572 (as amended);

• If the proposal/works are prohibited by a condition attached to a previous planning permission, enforcement notice, or Special Development Order (a site specific consideration);

• If the local planning authority (LPA) has imposed restrictions to remove the normal permitted development rights (known as Article 4, and Article 6 Direction) (a site specific consideration).

Summary of Noise Control Measures

9.97 The details contained in Table 9.5 below assume that normal ‘permitted development’ rights apply and explain some of the most frequently occurring restrictions to the normal permitted development rights.

9.98 By way of example, and of relevance to noise barriers, planning permission is generally not required for the erection, construction, maintenance, improvement or alteration of a gate, fence, wall or other means of enclosure up to 2 metres in height above ground level, or, if sited adjacent to a highway used by vehicular traffic, up to 1 metre. If the wall etc is to be sited within, or forming the boundary of a Listed Building planning permission would be required.

9.99 Table 9.5 should be read with an overall caveat that site-specific considerations would need to be checked prior to commencing the works.

9.100 It is generally advised that proposals are discussed with the local planning authority before any work begins. The planning authority will indicate any reason why the development may not be permitted and if planning permission is required for all or part of the work.



Table 9.5 - Planning Requirements for Noise Control Measures

No. Noise Control

Measure General requirements for Planning Consent Notes

NOISE BARRIERS

1 2m high noise barrier at edge of noise source when it is at grade.

Planning permission not normally required if sited adjacent to a highway and no higher than 1 metre, if not adjacent to a highway and no higher than 2 metres if not within or forming a boundary to the curtilage of a listed building

Refer to ‘Minor Operations’ below for details of the applicable restrictions.

Note that in some areas normal permitted development rights are restricted and may not be applicable.

If the works fall under permitted development, it is good practice to inform the relevant Local Planning Authority of proposals. Confirmation may be sought from the Authority that proposals are acceptable.

Where planning consent is required an application is to be made to the relevant Local Planning Authority who shall assess development proposals against the planning policy framework.

2 As 1, but barrier is 4m high

Planning permission normally required if in excess of 2 metres high.

Planning permission must be sought from the relevant Local Planning Authority who shall assess development proposals against the planning policy framework.

3 Noise barrier where road is elevated

If the barrier sits on a bund or is otherwise elevated, and the relative ground level exceeds 2 metres in height, planning permission is required.

It should be also noted that the permitted height of a fence is 2m as measured from ground level. In cases of embankments, parapets or uneven ground the efficacy and effect of any new barrier must be considered. In cases of uncertainty the Local Planning Authority should be consulted.

Where planning consent is required an application is to be made to the relevant Local Planning Authority who shall assess development proposals against the planning policy framework.

ROAD RE-SURFACING

4 Re-surface a road with a quieter road surface

Road re-surfacing would normally not require planning permission.

It is good practice to inform the relevant Local Planning Authority of proposals.

RAIL MAINTENANCE

5 Re-grind railway line

Maintenance works would normally not require planning permission.




No. Noise Control Measure

General requirements for Planning Consent Notes

BUILDING TREATMENTS

6 Replacement of windows in buildings with acoustically rated double or secondary glazing and provision of alternative means of ventilation.

Normally replacement of windows in a building (dwelling houses and other type of buildings such as industrial and commercial buildings, offices and shops) would not require planning permission where the size of the window has not been enlarged and/or does not materially affect the external appearance character of the building.

Exceptions to this would be where an Article 4 direction has removed these rights. Note that in some areas normal permitted development rights are restricted and may not be applicable.


Where development is proposed to be carried out under permitted development rights, the relevant Local Planning Authority should be informed of proposals. Confirmation may be sought from the Authority that proposals are acceptable.

ROAD TRAFFIC MANAGEMENT

7 Reduce the speed limit on a section of road

The alteration of road speed limits would not usually fall within the remit of the Town and Country Planning system and it would not be appropriate to seek such speed alterations via a planning application.

The preservation or improvement of amenity within an area through which a road runs (potentially including noise related to traffic) could be managed through speed restrictions implemented through a Traffic Regulation Order under the Road Traffic Regulation Act 1984.

The jurisdiction for such maters would fall to the relevant Highway Authority.

8 Implement a ban on heavy vehicles on a section of a busy road in a town centre

The regulation, restriction, or prohibition of road use by vehicle traffic or pedestrians may be implemented through a Traffic Regulation Order under the Road Traffic Regulation Act 1984.

Traffic restrictions may be agreed through a Section 106 agreement prior to planning consent for a proposed development. Traffic associated with a specific development may, for example, be forbidden from accessing a site via an inappropriate approach route.

The jurisdiction for such maters would fall to the relevant Highway Authority.



Building Control

9.101 External doors and windows are defined in the Building Regulations as “Controlled Fittings”, and have to meet statutory requirements. Guidance on how to meet the requirements of the Building Regulations is set out in a series of Approved Documents, published by the Department for Communities and Local Government. Any work that is subject to Building Regulations must comply with the requirements set out in the Approved Documents and is subject to approval by building control.

9.102 There are no particular acoustic requirements for controlled fittings set out in Approved Document E (Resistance to the passage of sound); however the design of measures to improve the acoustic performance of a building envelope is likely to impose an acoustic performance requirement on windows and doors. This acoustic performance requirement may either be met by the replacement of existing windows and doors or by the installation of secondary glazing and/or a second door, creating a lobby.

9.103 Building Regulations require reasonable provision for the conservation of fuel and power in buildings. Heat is lost through the building envelope, through all of the external components including windows and doors. Where these are to be replaced, any replacements need to meet the necessary heat-loss regulations, which are specified in terms of U values. The requirements for Controlled Fittings installed in an existing dwelling are set in Table 2 in Approved Document L1B (that covers fuel and power conservation).

9.104 Building Regulations require adequate means of ventilation in buildings. Typically, windows provide this ventilation within dwellings, although this can be provided through other systems. Building Regulations set out the ventilation requirements, and the type and extent of ventilation is dependent on the use and size of the room. Page 28 of the amended Approved Document F describes the requirements that are to be met where works are undertaken on existing buildings. If the proposal is to change the provision of ventilation from trickle vents to alternative means, for example through mechanical ventilation, then this system would need to comply with the requirements of Approved Document F (that covers ventilation).

9.105 If a system installer is registered with a competent person scheme (BSi, CERTASS or FENSA), they will be approved to carry out the work to comply with building regulations without involving local authority building control. When work is complete, a certificate is issued showing the work was carried out by the registered installer. Alternatively an unregistered installer could be employed, in which case approval would need to be sought from the relevant Building Control Body either at the local authority or by an approved inspector.

Chapter Summary

9.106 This Chapter has summarised other costs and benefits which occur for the different types of noise control measures being considered. The costs associated with the planning, design and installation of the noise control measures have been detailed along with approvals and consents that may be required. An overview of other environmental and sustainability impacts which may occur has been presented.



10. Framework for Cost Benefit Analysis

10.1 This chapter provides a brief overview of approaches to appraising options and also identifies some of the advantages and disadvantages of these approaches. Firstly, however, it provides context regarding option appraisal in UK central government. Further details are provided in Chapter 11 Toolkits on the implementation of a cost benefit analysis for remediation measures.

Options Appraisal in UK Central Government

10.2 In “The Green Book”,73 Her Majesty’s Treasury (HMT) provides a best practice guide to the conduct of assessments of projects, policies and programmes. This guidance is binding for government departments and executive agencies, although it can be (and is) supplemented by guidance in specific areas (e.g. TAG in transport).

10.3 The stated purpose of the Green Book “is to ensure that no policy, programme, or project is adopted without first having the answers to the following questions: Are there better ways to achieve this objective? Are there better uses for these resources?” (Pg 1).

10.4 The essential technique advocated by the Green Book is option appraisal. In brief, this comprises: justifying the rationale for government intervention; setting the objectives for the proposed intervention; creating and short-listing potential options for these objectives; and comparing (ideally in monetary terms) the costs and benefits of these options, including wider social costs and benefits. The process surrounding an option appraisal in greater detail is considered in the next chapter.

10.5 Cost Benefit Analysis (CBA) is the approach recommended by HMT in the Green Book for the appraisal of policies, programmes and projects. Recognising one of the disadvantages of CBA, the Green Book also recommends that the approach is proportionate. As a result, it is usual for CBAs to include non-monetised impacts (expressed either quantitatively or qualitatively). Such a constrained CBA is valuable in its own right but the conduct of the process itself also adds value

10.6 Appendix C provides definitions of CBA and other approaches to appraising options and lists some of their key advantages and disadvantages.

Appraisal and Evaluation in Context

10.7 Appraisal and evaluation are part of a broader project or policy lifecycle. This lifecycle, often referred to as ROAMEF (Rationale, Objective, Appraisal, Monitoring, Evaluation and Feedback), is characterised in the diagram presented below from the Green Book.



Figure 10.1 – Appraisal Lifecycle

10.8 In brief, the stages of this lifecycle are:

1. establish the rationale for intervention;

2. set the objectives of the proposed intervention;

3. conduct an appraisal to inform the decision as to the best intervention option;

4. implement and monitor the best option;

5. evaluate the implemented option at an appropriate time; and

6. feedback findings from the evaluation.

The Appraisal Process

10.9 As set out in the Green Book, within the above cycle, an appraisal comprises a number of steps, as described below.

Step1: Develop options and a base case

10.10 First, options to meet the objectives of the proposed intervention need to be developed. These options must include a “do-minimum” option. The do-minimum option will often be used as the base case against which other options are compared.

Step 2: Identify and value costs and benefits

10.11 Next, the costs and benefits of each option need to be identified and valued. In general, the hierarchy of valuation approach to adopt is as follows: the first best approach is to use actual market values, where available; the second best approach is to use values from complementary markets (i.e. revealed preference); the third best approach is to use values from ‘constructed’ markets (i.e. stated preference). More details on valuation techniques are provided in the Green Book. Having valued the various costs and benefits, there may be a need for adjusting them for the reasons described in the following steps.



Step 3: Distributional analysis

10.12 Distributional impacts are the effects of proposals on different sections of society. As a minimum, the appraisal should identify how costs and benefits accrue to different members of society (e.g. by age, gender, income, location, etc). It is also possible to make explicit adjustments to costs and benefits in recognition of distributional effects by using distributional weights (this works by assigning an index of superiority to the different groups impacted by the project). In practice, such explicit adjustments are rarely made. Distributional analysis improves the understanding of the fairness of proposals, their social impacts and their scale.

Step 4: Relative price movements

10.13 Relative price movements need to be taken into account. In particular, costs and benefits should be expressed in ‘real terms’ (or ‘constant prices’), as opposed to ‘nominal terms’ (or ‘current prices’). Where future values are expressed in nominal terms, this would require deflating future cash flows by forecast levels of the relevant deflator.

Step 5: Discounting

10.14 Discounting is a technique used to compare costs and benefits that occur in different time periods. It is based on the principle that people generally prefer to receive goods and services now rather than later. The discount rate is used to convert all costs and benefits to ‘present values’ and to enable comparisons. The recommended discount rate is 3.5%. Calculating the present value of the differences between a series of costs and benefits provides the net present value (NPV) of an option. The NPV is the primary criterion for deciding whether UK government action can be justified. An example of discounting is given in Chapter 8.

10.15 In theory, the time horizon of the infrastructure appraisal should equal the lifetime of the infrastructure or the assets created. However the appraisal period is often shorter than the lifetime of the infrastructure due to uncertainty. This introduces the issue of residual value and lifetime of components. Straight line depreciation (fixed % of original value per year) is the most common method for estimating the terminal/residual value. There is no consensus on lifetimes of components and average, minimum or maximum lifetimes can be used.

Step 6: Tax treatment

10.16 Where it may make a material difference there is a need to adjust the market prices for material differences in tax between options. However, in practice, it is relatively rare that adjustments for taxation are required, because similar tax regimes usually apply to different options.

Step 7: Risk, bias and uncertainty

10.17 Adjusting the valued costs and benefits for risk and bias aims to reconcile the differences between what is expected to happen and what eventually happens. In appraisals this difference is always likely to occur because of biases inherent in the appraisal (most notably “optimism bias”), and risks and uncertainties that may materialise. In general, to avoid the impression of “spurious accuracy”, estimates based on single values should be avoided in favour of using estimates based on either ranges or distributions. The sensitivity of conclusions to changes in key variables should be presented.

Step 8: Unvalued impacts

10.18 The costs and benefits of unvalued impacts should be identified and considered. This could be through using scoring and weighting techniques (if appropriate), by non-monetary quantification, or (as an absolute minimum) by a qualitative assessment, as described in the previous sections.

10.19 The above process for option appraisal is iterative and the best option is likely to require further refinements before a solution is implemented.



Practical Issues

10.20 Task 1.3 of the Defra NANR 201 Project requires that the practical issues of attempting to conduct monetary CBA of noise control projects are highlighted. Some of the main practical issues are summarised below. These will be investigated more closely as part of the case studies.

Option Development

10.21 A strict definition of a CBA requires the costs and benefits of a number of options to be compared against a base case. The options would need to be sufficiently developed at least to allow the potential costs and benefits of options to be identified.

Assessment Level

10.22 A CBA may have an advantage over CEA in that the costs and benefits are presented using the same metric (i.e. money) and this facilitates a better comparison of various options. Both the CBA and CEA of noise control measures in the true sense would require a detailed knowledge of the options, including the resulting noise level changes at all affected receptors. This level of detail may not be available, say, at a strategic level of assessment and certain assumptions may need to be made. As the assessment progresses to subsequent stages these assumptions could be tested and the range of uncertainty would likely reduce. Further information on the differences between CBA and CEA are provided in Appendix D.

Appraisal Period

10.23 Under the Environmental Noise Regulations, the Noise Action plans would need to be revised every five years. Therefore the list of remediation measures considered in a given action planning period will need to reflect this. However, it is desirable as part of a CBA to use a longer appraisal period of 60 years in accordance with policy. The assessment may be limited by the availability of reliable noise predictions, and assumptions would need to be made for the full appraisal period.

Design Life and Acoustic Life

10.24 For maximum acoustic effectiveness, a noise remediation measure in a locality may comprise a number of combined measures (say for example lower noise surface, a noise barrier and a HGV ban).

10.25 The design life of a measure would not necessarily reflect the length of time an option is expected to provide acoustic benefits (i.e. effective acoustic life). For instance, a noise barrier may be designed to maintain its structural, and therefore acoustic, integrity for up to 20 years. However a lower noise surface may have a structural life of 5 to 7 years, during which time it may gradually lose its acoustic effectiveness. On the other hand, a lorry ban along a route could reasonably be expected to have longer lasting acoustic benefits.

10.26 A risk of deterioration in acoustic performance could be allowed for in the noise assessment by applying a correction factor. For example in the DMRB, low noise surfaces are assumed to have a noise reduction performance of 3.5 dB over certain traffic speeds. This corresponds to a laboratory tested acoustic performance of 5 dB which allows for the acoustic deterioration over time by assuming 70% of its value. This approach could help reconcile the design life and the acoustic life.

10.27 As part of a CBA, a possible approach could be to value the individual noise remediation measures separately and to integrate the costs and benefits over the relevant assessment period for a full value of the combined measure. However it may not always be appropriate to assess multiple noise control options separately. For instance a barrier and a lower noise surface acting together may not necessarily give the same overall benefit as the sum of the individual benefits of the options. Appropriate assumptions may need to be made to deal with these on a case by case basis.



Unvalued Impacts

10.28 In selecting the best option, the Green Book explains that the best option is likely to be the one with the highest risk adjusted net present value (for a cost benefit analysis) or the option with the lowest net present cost (for a cost effectiveness analysis).

10.29 However in practice other factors, and in particular, unvalued costs and benefits will affect the selection of the best option. This would be where a significant impact has been identified but is not currently valued. For example, the visual impacts of a proposed noise barrier could be considered to be an ‘unvalued’ cost or benefit.

10.30 Unvalued costs and benefits could be compared using weighting and scoring techniques. As scores are not expressed in monetary terms, judgment is required to compare the results of weighting and scoring with the cost benefit or cost effectiveness analysis. This may introduce inconsistencies in the assessments when applied across the UK. Of course, in practice, this may not be a significant problem. CBA is most appropriately viewed as decision support method. The decision as to the option to implement ought to be informed by CBA but, it can be argued, appropriately rests with a responsible authority.

Strategic Noise Mapping

10.31 There may be a number of limitations associated with data available through strategic noise maps which could influence the outcome of noise valuation studies. For example noise-sensitive buildings are represented by a single receptor point which is assumed to be at 4m above local ground level. The noise levels at different floors of a multi-storey residential building may be quite different to those shown in strategic noise maps.

10.32 Action planning may require specific local noise control measures to be implemented. However without a reliable way of quantifying the baseline noise levels at all receptor positions, it may not be possible to design effective noise control. The benefits of noise control measures would vary depending on receptor height among other factors. Therefore without detailed calculations for both situations ‘with’ and ‘without’ a noise action, cost-benefit assessments may not give a true indication of the monetary value of noise control. Such uncertainties will need to be made explicit in the CBA.

Chapter Summary

10.33 This chapter highlighted some of the practical considerations of valuing the benefits of noise, which should be balanced as part of action plans against the costs of remediation measures. Further details on the implementation of a cost benefit analysis for remediation measures are provided in next chapter.



11. Toolkit

11.1 The toolkit described below contains the key information and requirements for each step in the assessment process. The toolkit should be read in conjunction with the rest of this report, and particularly Chapter 6 which describes the assessment method. The toolkit refers to the Good

Practice Guide for Noise Mapping produced by the WG AEN3.

Tool1: Identify Constraints and Opportunities

11.2 When noise control measures are being considered at a location, it is important to consider the noise level as experienced in the area. The purpose of this tool is to identify all the relevant information about an area being considered.

11.3 Broadly speaking, information is required about:

• The noise sources affecting the area;

• The noise sensitive receptors in the area;

• The propagation path between sources and receptors.

Noise Sources

11.4 The noise management areas considered by this study will be in the vicinity of a section of road or railway, as identified by the strategic noise maps. The consideration of noise control measures will need to consider all significant noise sources affecting this area.

11.5 The following tables should be completed for each noise source in the area. Traffic information should relate to the most recent data available. Where one of the parameters varies significantly, the source should be split into sub-sections.

11.6 Roads should be considered where vehicle flows are significant. Indicatively, roads should be considered where flows exceed approximately 1000 vehicles per day (in accordance with CRTN46) within 600m of the noise management area, and those with flows exceeding approximately 50,000 within 2km of the noise management area:

Table 11.1 – Source data requirements for roads

Road name/number 18hr AAWT traffic flow

% of HeavyVehicles

Average Traffic Speed

Road Surface and Condition

11.7 Where traffic flows are not available, reference should be made to the WG AEN Good Practice Guide Toolkits 2 to 7 for methods of obtaining traffic data for the roads in question.

11.8 For each railway line within 2km of the noise management area:

Table 11.2 – Source data requirements for railways

Train type Number passing in 18 hours

Average Pass- by Speed

Track Type, Support and Condition



11.9 The number of trains passing and track type will need to be established. Where train speeds are not available, reference should be made to the WG AEN Good Practice Guide Toolkit 9.

11.10 Aircraft noise should only be considered at locations near to airports, and reference made to available noise data, and levels at noise sensitive locations noted.

11.11 Other noise sources should be considered where the noise level from them is noticeable affecting noise sensitive locations:

Table 11.3 – Source data requirements for other sources

Noise Source Period LAeq

whilst operating Does the source operate

continuously or intermittently?

Noise Sensitive Locations

11.12 The primary basis for the selection of the noise management areas is people living in areas of high noise level, and therefore there will be residential properties in the noise management area. Other noise sensitive areas can be considered, particularly where they form an important community resource.

11.13 For residential properties the following information is required:

Table 11.4 – Source data requirements for residential properties

Building(s) Number of

dwellings

Number of floors

Height of ground

floor

Height increment for other floors

Facades with windows/

doors

Type of windows

11.14 This information can be grouped on a building by building basis, or similar buildings can be grouped together. The important information is the number of dwellings and number of floors.

11.15 The number of floors should indicate the number of floors with residential rooms, including loft conversions. The height of the ground floor and other floors should be noted, particularly where the ground floor is elevated above the local ground level or the floor-to-floor height is large.

11.16 Where this information is not known, use can be made of WG AEN Good Practice Guide Toolkits 15 and 20. The DMRB Volume 11, Section 3, Part 7 (HA213/08) also provides standard assumptions which can be used in the absence of better information.

11.17 The information relating to the types and locations of windows and doors is used in the consideration of noise control measures which improve the building envelope. The important information relates to the type of glazing – and the following broad types of window can be identified:

• Sealed façade – none of the windows in the building are openable. This implies that ventilation is typically provided by other means. Note also that buildings near major roads and railways may have also been provided with alternative ventilation provisions through the Noise Insulation Regulations (roads or railways).

• Double glazed – most modern buildings will have double glazed windows for thermal reasons, but ventilation is usually provided through trickle vents in the window frames or by having opeanble sections.



• Single glazed – older buildings will often have single glazed windows unless they have been replaced.

11.18 Similar information for non-residential noise sensitive buildings is required, and any amenity spaces should be identified. Chapter 4 provides further information on types of non-residential properties which could be included.

Propagation Paths

11.19 In order to calculate the potential benefits from noise control measures, noise calculations in three-dimensions are required. These should be undertaken using noise modelling software, although alternative methods could be considered.

11.20 Information on the heights of each noise source and the general ground topography is required. Ideally, this would be obtained from a digital terrain model of the noise management area, or from other available data.

11.21 Where such information is not known, reference should be made to the WG AEN Good Practice Guide, Toolkits 11 to 13 can be used.

11.22 Where there are existing noise barriers or other structures providing significant screening, these should be noted and included in the calculations. Note should also be made of retaining walls and other structures which may reflect noise.

Tool2: Scoping of Potential Noise Control Measures

11.23 The following checklists can be used to determine which general types of noise control measure can be included for consideration. These constraints are intended to be assessed quickly and without reference to other sources. Other constraints may be imposed on the area, as described in Tool 3

Table 11.5 – Scoping constraints for noise barriers

Issue Scoping

Access requirements at potential barrier location Exclude barrier options

Tall buildings Benefits limited at upper floors

Existing noise barriers or solid parapets Benefits may be limited

Table 11.6 - Scoping constraints for quieter road surfaces

Issue Scoping

Traffic speed/composition below effective range Exclude quieter surface options

Existing quieter road surface Benefits limited by existing surface

Special surfaces for other reasons Re-surfacing may not be possible

Limited height clearances Re-surfacing may not be possible

Table 11.7 - Scoping constraints for building envelope measures

Issue Scoping

Sealed façade present Exclude building envelope measures

Double glazing Benefits may be limited

Loft conversions, mansard roofs or dormer windows Benefits may be limited



Scoping constraints for road or rail maintenance works

11.24 There are no immediate constraints for maintenance works.

Scoping constraints for traffic management measures

11.25 There are no immediate constraints for traffic management measures.

Tool3: Scoping of Non-Acoustic Considerations

11.26 The following tables describes which other types of assessment may be required for different types of noise control measures. Where a tick is shown an assessment may be required. A scoping opinion could be sought from a relevant specialist at an early concept stage, which may additionally exclude particular measures from further consideration.

Table 11.8 – Scoping for Environmental Assessments

Environmental Assessment Likely?

Air

Qu

ality

an

d G

reen

hous

e G

asse

s

E

colo

gy

C

ultu

ral H

erita

ge

Land

scap

e, T

ow

nsca

pe a

nd

Vis

ual E

ffect

s

C

om

mun

ity E

ffec

ts

F

lood

Ris

k a

nd D

rain

age

W

ater

Qua

lity

G

eolo

gy a

nd

Soi

ls

Noi

se C

ontr

ol

Mea

sure

Noise Barriers

Road Re-surfacing

Rail Maintenance

Building Treatments




Table 11.9 – Scoping for Other Assessments, Approvals and Consents

Assessment Likely?

Pla

nnin

g P

erm

issi

on

B

uild

ing

Co

ntro

l

T

rans

port

Ass

essm

ent

Sus

tain

ab

ility

Ass

ess

me

nt

In

fras

truc

ture

Cos

ts

Use

r C

osts

and

Be

nefit

s

E

xter

nalit

ies

Indi

rect

Soc

io-e

con

omic

Co

sts

Noi

se C

ontr

ol

Mea

sure

Noise Barriers

Road Re-surfacing

Rail Maintenance

Building Treatments


Tool4: Definition of Scenarios

11.27 In order to undertake a cost and benefit analysis for noise control measures at least two different options or scenarios are required for comparison. To demonstrate that the benefits offered by the noise control measure are effective, each scenario should be considered in terms of a design target. In addition, a do-minimum assessment is required if there are planned activities which may affect the noise levels.

11.28 Each scenario should be set in a study area. The study area should extend from the noise control measure to include all noise sensitive locations where noise decrease or increase by at least 1dB. Noise levels below 55dB do not normally need to be considered.

11.29 The extent of the study area required will depend on the size of the noise management area being considered, and the proximity of other noise sources. At the largest, the study area may need to include locations some 800m from the source, but more typically, other noise sources will contribute at these distances, masking the potential benefit from the noise control measure.

11.30 Study areas should initially extend at least 300m back from the source being controlled; however where there are no other major noise sources in the area, this distance may need to be extended back to 400-500m.

11.31 The length of the study area should extend beyond the noise control measures by the same length as the distance back.

11.32 Even if the noise management area is on one side of a source, the study area should include properties on both sides of the source, so that any adverse effects from reflective noise barriers are taken into account.

11.33 Several iterations of study area definition may be required to determine that all changes in noise greater than 1dB are included.



11.34 Chapter 6 of this report provides advice on the definition of scenarios, the selection of design targets and the significance of changes in noise levels.

Tool5: Method of Calculation

11.35 This tool summarises the method of calculation for each type of noise control measures considered.

Table 11.10 – Methods of Calculation

Noise Control Measure Calculation Method

Rail Grinding and Wheel Turning Use CRN and apply a track/track support correction in the noise model to the sections of track being treated

Rail Pad Replacement Use CRN and apply a track/track support correction in the noise model to the sections of track being treated

Alternative Road Surfaces Use CRTN, and apply a correction to the basic noise level to sections of road where the traffic characteristics meet the requirements for the surface, e.g. speed > 75kph.

Altering Road Traffic Flows and imposing vehicle restrictions.

Use CRTN, and adjust the basic noise level according to the changes in traffic flows. This may require the output of a traffic model.

Altering Rail Traffic Flows and imposing vehicle restrictions.

Use CRN, and adjust the reference noise level according to the changes in traffic. This may require the output of a traffic model.

Speed Restrictions for Road Traffic

Use CRTN, and adjust the basic noise level according to the changes in traffic flows. This may require the output of a traffic model.

Speed Restrictions for Rail Traffic Use CRN, and adjust the reference noise level according to the changes in traffic. This may require the output of a traffic model.

Simple Noise Barriers Use CRN or CRTN and use the barrier attenuation procedures described.

Tunnels or Full Covers Remove the sections of road or track which are covered from the CRN or CRTN noise model

Other Types of Barrier Add an appropriate notional height to the simple barrier and use the CRN/CRTN barrier procedure, see Appendix B12

Noise insulation of properties Use CRN or CRTN to calculate the noise level just outside each property. Use advice in Appendix F to evaluate the acoustic benefits.

11.36 Detailed calculations are required in order to establish the potential benefit from noise control measures. The information collected using Tool 1 should be used as the input parameters for noise calculations.

11.37 Calculations should be undertaken for the year when the mitigation measure is being installed. If the measure does not influence traffic flows, then the noise levels are assumed to remain constant, and the benefits of the measure apply for the full appraisal period. If the measure changes traffic flows, then a traffic model is required, and forecasts are required for a future year.

11.38 If the measure does not affect traffic flows, and forecast traffic data is not available for the installation year, then the closest reliable traffic data should be used in the assessment.



Tool6: Calculation Points

11.39 An important part of the calculation process is the positioning of the calculation points. For any property being considered, the effectiveness of the noise control measure should be assessed by considering the smallest benefit or largest dis-benefit on the façade with the highest noise level.

11.40 The objective is to have every property in the study area represented by an appropriate calculation point. Therefore, there needs to be a matching or assigning process to identify which properties are represented by which calculation point.

More than one calculation point per property

11.41 For situations where there is more than one calculation on an individual dwelling, the calculation point should be selected for that dwelling which meets the smallest benefit/highest noise level criteria.

11.42 For properties with more than one storey, this will often apply to the highest storey, and for properties with more than one façade, the highest noise levels will often be at the façade closest to, and with the greatest angle of view over the noise source.

More than one dwelling per building

11.43 For buildings containing more than one dwelling, for example a block of flats, care should be taken in assigning calculation points, particularly where different dwellings look out on different facades. In this case, property counts may need to be assigned to calculation points on more than one façade.

11.44 Further information is provided in the WG AEN Good Practice Guide Toolkits 21.

Use of representative calculation points

11.45 It is not essential to have separate calculation points for every dwelling or building; however it may be more straightforward to do this. It is entirely reasonable to use single calculation points to be representative of a number of dwellings, particularly with terraced housing or semi-detached houses where these are aligned parallel to the noise source.

11.46 Care should be taken to ensure that all the properties in the area are included in the assignment of property counts, and also that if there is a mix of numbers of storeys (for example some houses have loft conversions), then these are assigned appropriately.

11.47 Judgement should be used where such groups of properties are not parallel with the noise source, or where there are other noise sources which may give rise to different noise levels in different areas. Where this is the case additional calculation points should be inserted.

11.48 Where a noise control measure may affect parts of such a group of properties differently, for example because they are near to the end of a noise barrier, then additional calculation points should be added to account for this variation.

Benefits on other facades

11.49 Where a noise control measure is bringing a benefit on the façade of a building which is not the nosiest, for example at the rear of some houses which front onto a different road, then these may be included in the assessment, but a note made that the benefits are not received at the façade of the building with the highest noise levels.

Tool7: Internal Noise Levels

11.50 For an initial assessment, it should be assumed that improvements from building envelope treatments provide a 15dB improvement. This assumes that buildings currently have double glazing, but these are required to be opened to provide background ventilation to the property.



The 15dB improvement includes the provision of alternative ventilation allowing the windows to remain closed, and any necessary improvements to the windows, including sealing.

11.51 During a later design iteration, the particular improvement expected at each property can be assessed individually. Account can be taken of the individual windows in each property, and the appropriate improvement assigned. For the purposes of summarising the acoustic benefits, where there are a range of different windows types in a property the smallest improvement should recorded and included in the valuation. Only noise sensitive rooms should be considered in the assessment – i.e. living rooms and bedrooms.

Tool8: Assessment of Acoustic Benefits

11.52 The results of the noise calculations should be presented using the results tables in Chapter 6 for residential and non-residential noise sensitive receptors. These present a summary of the acoustic changes resulting from the noise control measure.

11.53 For residential properties, the objective is to identify the present value of the change in noise. This should be calculated using the advice in Chapter 8 and in TAG unit 3.3.2. Note that currently there is no method available for valuing the acoustic benefits from building envelope measures.

11.54 For non residential locations a significance rating should be determined using the advice in Chapter 4. No valuation is required.

11.55 For each option being considered, the following summary of acoustic benefits should be completed to present the results.

Table 11.11 – Summary of Acoustic Benefits

Option:

Residential properties Change in present value: £

Non residential locations Significant changes:

Tool9: Assessment of Non-Acoustic Costs and Benefits

11.56 Once the noise control measures have been optimised, the advice in Chapter 7 should be used to estimate the costs of implementing the noise control measure. Costs associated with the design and installation of the noise control measure should also be estimated.

11.57 In addition, the maintenance and running costs of the measure should be identified for the appraisal period, so that these costs can be included in the cost benefit analysis. Where a maintenance programme is planned, details of the activities on a year-by-year basis are required.

11.58 If the noise control measure has a shorter design life than the appraisal period, then the maintenance programme should include replacements.

11.59 Use Tool 3 to determine which other assessment types are required for each option being considered. In each case where an assessment is required, the assessment should monetise any impacts where advice exists that allows this to be undertaken, or impacts should be scored on a significance scale where a monetary value cannot be calculated.

11.60 At the early stages of the development of a noise control measure, if Tool 3 identifies that a non- acoustic assessment may be required and there is insufficient information to undertake this, the report needs to identify that the non-acoustic assessment has not been undertaken and an appropriate risk or caveat recorded in the assessment summary.



Tool10: Collation of Assessment Data

11.61 All of the assessment data should be collated together for inclusion in the cost benefit analysis. The following proforma is based on the Appraisal Summary Table in TAG unit 2.7.2. A table should be completed for each option being considered.

11.62 Where a particular assessment has been demonstrated as not required this should be indicated in the “key comments/observations” column

Table 11.12 – Assessment Summary

Assessment Key Comments/ Observations

Unvalued Scores

Monetary Value

Noise Residential buildings

Non-residential locations

Measures Design costs

Planning costs

Purchase costs

Installation costs

Maintenance costs

Environmental Air Quality

Greenhouse Gasses

Ecology

Cultural Heritage

Landscape / Townscape

Visual Effects

Community Effects

Flood Risk

Drainage

Water Quality

Geology and Soils

Sustainability

Approvals Planning

Building Control

Safety Accidents

Security

Economy Public Accounts

Transport Economic Efficiency: Business Users & Transport Providers

Transport Economic



Assessment Key Comments/

Observations Unvalued

Scores Monetary

Value

Efficiency: Consumers

Reliability

Wider economic impacts

Integration Other government policies

Tool11: Cost Benefit Analysis

11.63 The procedure for undertaking the cost benefit analysis is described in Chapter 10. The TAG guidance for noise gives a net present value for the acoustic results, and the guidance in TAG for the other environmental disciplines allows any of those impacts to be assessed and presented in a similar basis.

11.64 Where a traffic assessment has been undertaken then the economic costs and benefits can also be assessed and presented using the advice in TAG.

11.65 The costs associated with the design, procurement, installation, maintenance and running of the noise control measures need to be discounted so that the net present value of these costs can be determined.

Tool12: Reporting

11.66 Each option considered within a noise management area should be compared. The summary table and cost benefit analysis should provide sufficient information to inform a decision about the selection of the most appropriate noise control measure, or it should identify if further options should be tested.

11.67 Any decisions made on the selection of particular options, or for examining alterative options, should be recorded with appropriate justifications for inclusion in the overall report for the noise management area.

11.68 Overall, the results of all options considered should be compiled into a report for the noise management area, as described in Chapter 5 of this report. The suggested report structure is:

• Introduction, describing existing situation and noise levels;

• Planned works and schemes, describing any do-minimum activities;

• Scoping, describing the results of scoping exercise including measures excluded;

• Scenarios Considered, describing each of the scenarios considered;

• Results, description and summary table for each scenario/option, and any key features, and estimation of costs for each noise control measure;

• Non-Acoustic Studies, description of non-acoustic studies and key results;

• Cost Benefit Analysis, the cost benefit analysis and results.

Chapter Summary

11.69 This chapter has set out in a step by step manner the detail of the steps that are required to consider the costs and benefits of noise control measures.



12. Toolkit Example

12.1 This chapter describes an idealised simple example of the toolkit to demonstrate the processes described above.

Tool1: Identify Constraints and Opportunities

Noise Sources

12.2 The noise management area is a group of properties next to a dual carriageway in a predominantly rural situation. There are no other significant noise sources in the area

Table 12.1 - Source data requirements for roads

Road name/number 18hr AAWT traffic flow

% of HeavyVehicles

Average Traffic Speed

Road Surface and Condition

A666 60,000 20 80kph HRA, reasonable

Noise Sensitive Locations

12.3 The properties are grouped together in a small site, and are accessed from a private road. There are three buildings of three storeys; each storey contains four apartments, giving a total of 36 properties in the area. The buildings are all of a brick/block construction, and the buildings have flat roofs. They were constructed in the 1970’s. There are no other noise sensitive locations within 500m of these properties. A plan is shown in the figure below. The plan is not to scale.

Figure 12.1 – Plan showing worked example

Table12.2 – Source data requirements for residential properties

Building(s) Number of dwellings

Number of floors

Height of

ground floor

Height increment for other

floors

Facades with

windows/ doors

Type of windows

A (20m from road) 12 3 0 3 See below Double glazed

B (50m from road) 12 3 0 3 See below Double glazed

C (80m from road) 12 3 0 3 See below Double glazed



12.4 In each case, two of the apartments on each floor look over the road and two of the apartments look away from the road. There are no windows or doors on the side facades of the buildings.

Propagation Paths

12.5 The ground between the properties and the road is flat and level. The road is at grade. The buildings are set in communal gardens between the buildings and the highway. There is an open wire fence at the boundary between the highway and the properties, and there are no other features which would affect the noise propagation.

Tool2: Scoping of Potential Noise Control Measures

12.6 Barriers, quieter surfacing and building envelope measures can all be considered for this situation.

Tool3: Scoping of Non-Acoustic Considerations

12.7 For the purposes of this example, it is assumed that all of the other environmental topics do not require an assessment, and that no other costs or benefits are associated with the options.

Tool4: Definition of Scenarios

12.8 The design target for this example is to reduce the noise levels at the six properties in the building closest to the road, overlooking the carriageway, by at least 3dB.

12.9 As there are only three buildings in this area, the study area only needs to consider these buildings.

Tool5: Method of Calculation

12.10 The methods described in the toolkit have been used for the calculations.

12.11 The measures considered do not affect the traffic flows. The calculations use traffic data for the current year, as this is the only traffic data relevant for determining the performance of mitigation measures.

Tool6: Calculation Points

12.12 A single calculation point is used on each floor of the front and back facades of each building, each calculation point is representative of the two properties on that floor.

Tool7: Internal Noise Levels

12.13 The properties currently have double glazed windows, but these have trickle vents which are required to be opened for ventilation. Any measure for building envelope improvement would therefore need to replace the windows and provide an alternative means of ventilation.

Tool8: Assessment of Acoustic Benefits

12.14 Do minimum calculations show that the building nearest the road has noise levels between 75 and 80 dB LA10,18h on the façade facing the road, and noise levels are some 20dB lower on the rear façade. Noise levels are some 5dB lower at the second building and 10dB lower at the third building.

12.15 The results for the following options are presented:

a) 100m long, 2m high barrier

b) 200m long, 2m high barrier



c) 100m long, 4m high barrier

d) 200m long, 4m high barrier

e) 400m of quieter road surfacing (road width 15m, giving a total area of 6000m2)

Table12.3 –Changes in Noise Summary – Study a

Option/Comparison: 100m long, 2m high barrier











0 6

0.1 – 0.9

1 – 2.9

3 – 4.9

5 +

0

0

0

0

16

12

2

0

Total (change 1+) 0 14


Table12.4 –Changes in Noise Summary – Study b












0 4

0.1 – 0.9

1 – 2.9

3 – 4.9

5 +

0

0

0

0

16

12

4

0





Table12.5 –Changes in Noise Summary – Study c












0 0

0.1 – 0.9

1 – 2.9

3 – 4.9

5 +

0

0

0

0

18

12

2

4



Table12.6 –Changes in Noise Summary – Study d












0 0

0.1 – 0.9

1 – 2.9

3 – 4.9

5 +

0

0

0

0

14

6

10

6





Table12.7 –Changes in Noise Summary – Study e

Option/Comparison: Road surfacing











0 0

0.1 – 0.9

1 – 2.9

3 – 4.9

5 +

0

0

0

0

0

0

36

0



12.16 Of the options tested, the 2m barriers do not meet the design target as the noise levels on the top floor of the buildings are not reduced by 3dB. All the other options meet the design target. It would be possible to investigate barrier heights between 2m and 4m to determine if an intervening height would also meet the target.

12.17 As there are no non-residential properties in the study area, the change in net present value for all options is presented in the following table;

Table12.8 – Summary of Acoustic Benefits

Option Design Target Met? Change in Net Present Value from Changes in Noise

a) 100m long 2m high barrier No NPV: +£96k

b) 200m long 2m high barrier No NPV: +£118k

c) 100m long 4m high barrier Yes NPV: +£146k

d) 200m long 4m high barrier Yes NPV: +£212k

e) Road surfacing Yes NPV: +£151k

Tool9: Assessment of Non-Acoustic Costs and Benefits

12.18 The case study has considered both timber and concrete noise barriers, and replacing the existing hot rolled asphalt with a thin wearing course.

12.19 For barriers, it has been assumed that timber barriers require replacement every 20 years, and that 10% of the initial cost before allowances needs to be spent every 10 years for maintenance. It has been assumed that concrete barriers do not require replacement, but they do require 10% of the initial cost before allowances to be spent every 10 years for maintenance.



Table12.9 – Costs of Barriers

Element Basis Cost for 2m Cost for 4m

Supply & install timber barrier £210/m (3m high) £150/m 310/m

Allowances for initial build 60% £90/m £186/m

Initial cost for timber barriers £240/m £496/m

Regular maintenance 10% of original £15/m £31/m

Allowances for replacement 30% £45/m £93/m

Replacement cost for timber barriers £195/m £403/m

Supply & install concrete barrier £360/m (3m high) £250/m £540/m

Allowances for initial build 60% £150/m £324/m

Initial cost for concrete barriers £400/m £864/m

Regular maintenance 10% of original £25/m £54/m

12.20 For surfacing, the costs of the measure are the difference between the resurfacing costs

associated with the hot rolled asphalt surface and the resurfacing costs associated with the thin wearing course, which has a shorter design life. This has been assumed because the road would require resurfacing anyway. Costs associated with the road substructure have not been considered, as this would be required regardless of whether or not the measure goes ahead, and it has been assumed that the design of this element does not change with the measure in place.

Table12.10 – Costs of Re-surfacing

Element Basis Cost for 6000m2

Planing top surface layer – added to both £2/m2 £12,000

Hot rolled asphalt (design life 15 years) £8/m2 £48,000

Stone Mastic Asphalt (design life 12 years) £12/m2 £72,000

12.21 All replacement and maintenance costs have been discounted at 3.5% per year over the 60 year

appraisal period.

Table12.11 – Summary of Noise Control Measure Costs

Net Present Value for Noise Control Measures

100m long 2m high timber barrier NPV: -£41k




100m long 2m high concrete barrier NPV: -£45k




Road surfacing NPV: -£88k



12.22 For the purposes of the worked example, no other assessments have been carried out, but the advice in Chapter 9 and Tool 3 indicates that other assessments would be required, and the results of these may affect the outcome of the cost benefit study.

Tool10: Collation of Assessment Data

12.23 The following table compares the benefits from the improvements in noise levels with the costs of the noise control measures.

Table12.12 – Simple Comparison of Costs and Benefits

Measure Acoustic Benefit

Economic Cost of

Measure

Net Change

100m long 2m high timber barrier NPV: +£96k NPV: -£41k +£55k




100m long 2m high concrete barrier NPV: +£96k NPV: -£45k +£51k




Road surfacing NPV: +£151k NPV: -£88k +£63k

12.24 This table shows that in all cases the measures provide more acoustic benefit than are incurred in costs, although it is noted that there would be other costs for the measures which have not been included in this worked example.

12.25 The results for the 100m long, 4m high concrete barrier have been filled out in the assessment summary table, although the other costs and benefits have not been estimated or included.

Table12.13 – Assessment Summary

Assessment:

100m long 4m high concrete barrier option

Key Comments/ Observations

Unvalued Scores

Monetary Value

Noise Residential buildings Design target met +£146k

Non-residential locations n/a

Measures Design costs

Planning costs

Purchase costs -£97k

Installation costs

Maintenance costs

Environmental Air Quality n/a

Greenhouse Gasses n/a

Ecology This would be required



Assessment:

100m long 4m high concrete barrier option

Key Comments/ Observations

Unvalued Scores

Monetary Value

Cultural Heritage This would be required

Landscape / Townscape This would be required

Visual Effects This would be required

Community Effects This would be required

Flood Risk This would be required

Drainage This would be required

Water Quality This would be required

Geology and Soils This would be required

Sustainability This would be required

Approvals Planning This would be required

Building Control n/a

Safety Accidents

Security

Economy Public Accounts n/a – no change in traffic

Transport Economic Efficiency: Business Users & Transport Providers

n/a – no change in traffic

Transport Economic Efficiency: Consumers

n/a – no change in traffic

Reliability n/a – no change in traffic

Wider economic impacts n/a – no change in traffic

Integration Other government policies

Chapter Summary

12.26 This chapter has set out a simplified worked example of the steps required in order to consider the costs and benefits of a range of noise control measures. It has focussed on the acoustic benefits and the installation and maintenance of the noise control measures, and acknowledges that there would be other costs and benefits which would need to be taken into account in a real example.



13. Case Studies

13.1 A range of case studies have been selected to allow different elements of the assessment method and toolkit to be tested to provide some sensitivity testing on key issues and to provide some examples of the assessment method being implemented.

13.2 Overall, the case studies have been selected to allow results to be assessed for the main different types of noise control measure against a range of urban and rural situations, including both high- rise and low-rise buildings, and covering a range of building ages.

Case Study Analyses

13.3 The case studies were selected to allow the following detailed analyses:

Study Area Size

13.4 By including a range of different configurations and having the case studies based on real situations, the distance from the noise sources where a 1dB change in noise is calculated can be assessed, to inform the initial selection of study areas.

13.5 The greatest monetary values will be at the higher noise levels, particularly where the changes in noise are the greatest. Lower noise levels, which are typically further from the noise source, will have less influence on the valuation. Tests have been undertaken to establish if a lower noise level can be determined, such that any impacts where noise levels are below this level would have a negligible impact on the overall valuation .

Calculation Approximations

13.6 The results of the case studies will show, in detail, the changes in noise from different measures. These can be analysed to identify suitable “ballpark” estimates for noise control measures.

Significance of Options

13.7 The results from the different case studies can be used to examine if there are any particular types of noise control measure which are shown to produce favourable results or generally can be excluded at a scoping level assessment.

Selection of Case Studies

13.8 A total of 15 case studies have been selected covering road and rail sources. The following table identifies the selected case studies.

Table 13.1 – Case Study Characteristics

No. Source Location Characteristics

1 Road – Dual c-way Urban area Road in retained cutting

2 Road – Dual c-way Suburban area Road generally at grade

3 Road – Dual c-way Urban area Elevated road

4 Road – Mixed dual/single Urban area Road at grade

5 Road – Motorway Edge of town Properties higher than road

6a Road – Dual c-way Edge of town Road at grade, near junction

6b Road – Dual c-way Edge of town Road in cutting / at grade

7 Road – Single c-way Suburban area Road at grade



No. Source Location Characteristics

8 Road – Mixed dual/single Rural area Road at grade

9 Road – Dual c-way Rural – near town Road elevated

10 Road – Single c-way Small town Road at grade

11 Road – Single c-way Edge of suburbs Road at grade

12 Rail – Branch line Suburban area Rail in cutting

13 Rail – Branch line Suburban area Rail in cutting

14 Rail – Main line Urban area Elevated rail line

15 Rail – Main line Urban area Rail at grade / shallow cutting

Basis for selection

13.9 All of the case studies are based on selected parts of existing noise models that Atkins has undertaken for other projects, and have been used with the permission of Atkins’ relevant clients. The selected parts of the noise models have been chosen to ensure that a broad set of road and rail conditions are modelled.

13.10 The principle for the selection of each of the case studies is that a section of road or railway in the noise model has been identified as one which requires consideration for noise control measures. The case studies were selected prior to the issue of the maps identifying first priority locations on the Defra website.

13.11 Because the case studies do not reflect real Noise Management Areas, they must be regarded as hypothetical examples.

Road Case Studies

13.12 The road case studies are all based on models used for projects predicting road noise levels. The traffic flows, speeds and proportion of heavy vehicles are all unchanged from the noise model used, and therefore these represent typical traffic flows for each type of road considered.

Rail Case Studies

13.13 The rail case studies have been derived from noise models used to predict road traffic noise levels, but the ground information relating to the height of rail line relative to existing ground levels was included in the noise model, allowing the rail line to be modelled appropriately. The rail lines have been added as noise sources, and train services have been derived by reference to typical train services on lines. Two train source scenarios have been considered for each scenario, one which includes only trains whose source height is at the rail head, and another which additionally includes some diesel locomotives on full power, with a source height 4m above rail level.

Basis for analysis

13.14 In each case, the analysis was limited to the potential benefits for the different measures. The following procedure was adopted:

• Examine the noise map for the noise model, and identify an area where noise levels are higher than other areas on the map. Use this area as the Noise Management Area for consideration of noise control measures.

• Concentrate on buildings where noise levels are at least 60dB as the Noise Management Areas are identified as the areas with the highest noise levels.



• Test a range of noise control measures to determine the effectiveness of these in the given situation. Where noise barriers are considered, a range of heights is considered between 1.5m and 4m, in increments no smaller than 0.5m.

• Summarise and monetise the benefits using the DMRB table and TAG spreadsheet. Estimate the costs of the noise control measure from the information in Chapter 7.

• Concentrate on residential properties only.

13.15 Design targets have not been set for the case studies, as the objective is to test the above items. It is straightforward to assess if results meet a design target, as shown in the worked example in Chapter 12.

Noise Control Options Tested

13.16 The following table describes which types of noise control measure have been tested for each of the case studies.

13.17 All road case studies have been examined for consideration of quieter road surface. Only those where traffic speeds are above 75kph have been considered for a quieter surface in line with the latest advice from the DMRB.

13.18 Barriers have been considered for each case study. In some areas, properties require access directly onto the road, and suitable locations for noise barriers are limited.

13.19 In addition to the case studies shown in the table below, a single case study was selected to evaluate the potential effectiveness of using traffic management techniques to control noise levels.

Table 13.2 – Noise Control Measures Tested

No. Case Study Noise Barrier Road Surface

1 Urban dual c-way in cut Yes Yes

2 Suburban dual c-way at grade Yes No

3 Urban elevated dual c-way Yes No

4 Urban dual/single c-way Limited No

5 Edge of town motorway Yes Yes

6a Edge of town dual c-way nr junc Yes No

6b Edge of town dual c-way in cut Yes Yes

7 Suburban single c-way at grade Limited No

8 Rural dual/single c-way Yes No

9 Rural dual c-way near town Yes No

10 Single c-way in small town Limited No

11 Single c-way at edge of suburbs Yes No

12 Branch rail line in cutting Yes N/A

13 Branch rail line at grade Yes N/A

14 Elevated Main rail line Yes N/A

15 Main rail line at grade Yes N/A



Review of Case Study Results

13.20 Summary results of the calculations undertaken in each case study are presented in Appendix E. For each case study, it has been assumed that:

• Where noise barriers are used as a noise control measure, these are timber barriers. It has been assumed that these barriers would require replacement approximately every 20 years, and would require limited regular maintenance. The net present value of the barriers, including replacements and maintenance over the appraisal period is assumed to be 1.7 times the initial costs outlined in the table below.

• Where road surfaces are used, a stone mastic asphalt has been used which replaces a hot rolled asphalt with a thin wearing course. The level maintenance (i.e. resurfacing) of a hot rolled asphalt surface is lower than that of a thin wearing course. Over the appraisal period, the installation and maintenance of a thin wearing course would give rise to a net present value which is higher than that for hot rolled asphalt by approximately the initial cost of the thin wearing course. The assessment takes the difference between these costs as the cost for this measure. This method is described in the worked example in Tool 9 in chapter 12.

13.21 The assumptions made for life expectancy, maintenance regimen and costs for the noise control measures for these case studies are for illustrative purposes only. There is a high level of uncertainty in the assumed costs for each noise control measure arising from potential differences in site locations, conditions and works required for each installation. The results of the case studies have focussed on the potential acoustic benefits of the noise control measures.

13.22 All the case studies compare the net present value of the acoustic benefits with the net present value of the installation and maintenance of the noise control measure. In each case study the mitigation measure is assumed to be installed in 2013, and the appraisal has been undertaken over a 60 year period. It is likely that other costs would be incurred in each case, and there may be additional benefits. Neither of these have been assessed or included.

13.23 For the case studies, a comparison has been made between the net present value of the changes in noise and the net present value of the costs of the measure. In order to compare the results within a case study the option which provides the greatest improvement in present value has been identified as providing the ‘best value for money’. When the full costs and benefits of the option have been assessed, those which meet the design criteria could be compared using a cost effectiveness analysis.

Barrier Costs

13.24 The basis for the barriers costs is set out in the following table. It has been assumed that all barriers for road case studies would require traffic management and safety protection, and, the economic cost is taken to be three times the initial cost. Similarly the economic cost for barriers for the rail case studies is taken to be 2.5times the initial cost. For completeness the economic cost for highway barriers without traffic management, at twice the initial cost is also given. The derivation of these economic cost estimates is set out in Section 8.

13.25 The initial costs for barriers are based on the costs from Table 7.3, with barrier heights other than 3m determined as described in Section 7. All initial costs have been rounded to the nearest £10 due to the uncertainty in the barrier costs.

Table 13.3 – Case Study Barrier Costs

Element Initial Cost Economic Cost – Highway (with

traffic management)

Economic Cost - Rail

Economic Cost – Highway without

traffic management

Reflective 1.5m Barrier £120/m £360/m £300/m £240/m








Absorbent 1.5m Barrier £200/m £600/m £500/m £400/m




Resurfacing Costs

13.26 As described in Section 8, the economic costs for resurfacing with a quieter road surface is taken to be the equivalent of the initial cost of providing the measure.

Case study 1

13.27 This study area includes three tower blocks of 16 floors to the north of the road, and two storey residential properties, mostly semi-detached to the south. The road passes close to both sets of properties. Traffic speeds are above 75kph, and this allows a quieter surface to be tested.

13.28 The road is in a retained cutting, with substantial walls of approximately 2m height on both sides. and the noise control options have looked at replacing these walls with purpose built noise barriers of 4m height, both reflective and absorbent, and resurfacing the carriageway.

Option Length Width Height Area

Reflective Barrier – north 342 - 4.0 1368

Reflective Barrier – south 434 - 4.0 1736

Resurfacing – EB 515 8.5 - 4378

Resurfacing – WB 515 8.5 - 4738

13.29 252 properties were considered, 192 in the three tower blocks and 60 to the south of the road.

Increasing the noise control to the north, to protect the blocks of flats produces neutral changes in noise at over half of those properties. Adding this to the south of the road gives improvements at over half the properties considered.

13.30 Resurfacing gives a slight change in noise at all properties considered because noise contributions from other roads are not significant. Combining the surfacing with the barriers



improves the results further. As the walls of the retained cut are reflective, no further benefit was obtained from using absorbent barriers in place of reflective at the top of the cutting.

13.31 In terms of costs, provision of quieter road surfacing is the cheapest option, and this also provides the best value for money. The costs of the barriers is typically higher than the value of the acoustic benefits.

Case study 2

13.32 This study area considered a group of 14 two storey properties adjacent to a dual carriageway, with access from a side road to the opposite side of these buildings, allowing a barrier between the properties and the dual carriageway. The road is generally at grade, with parts in a shallow cutting. Traffic speeds were too low to consider a quieter surfacing option. 2m and 4m barriers were tested at lengths of 150m, 200, and 250m.


Reflective Barrier 150 - 2.0 300






13.33 For this case study, the 4m barriers give better reductions in noise than the 2m barriers, and the

longer barriers give better results than the shorter barriers. In the majority of cases the monetary value of the acoustic benefits is greater than the cost of the mitigation measure. The options tested with the best value for money were the barriers at 2m height.

Case study 3

13.34 This study area includes five tower blocks each with 20 floors, and a large number of 4-8 storey residential apartment blocks, all to the north of the road. The road passes close to both a tower block and an apartment block, with the remaining tower blocks and apartment blocks being set further back. Traffic speeds are below 75kph, and therefore a quieter surface could not be tested.



13.35 The ground is generally flat, with the road elevated at an approximate height of between 8-16m above the local ground level. The mitigation options have looked at introducing a noise barrier to the north of the carriageway, and also introducing noise barriers to both sides of the carriageway (effectively forming bridge parapets). 1799 properties were considered. Barrier heights were tested between 1.5m and 4m in 0.5m increments.


Reflective Barrier – North 715 - 1.5 1073






Reflective Barrier – South 715 - 1.5 1073






13.36 In each scenario tested, increasing the height of the barriers gave rise to a better acoustic performance, and where the single barrier is considered, each height increment gained a greater acoustic benefit than the additional cost of the larger barrier. Where both barriers are considered, the shortest barrier option gives the greatest value for money.

13.37 The scenario where barriers were included on both sides of the road used reflective barriers, and tests the reduction in performance from reflections between the barriers. These results show that each increased barrier height gives a better acoustic performance, but the benefits are lower than the single barrier test.

Case study 4

13.38 This case study considered a busy section of urban road with properties requiring direct access to the pavement, and a number of side roads and vehicle access points. Over the length of road in the study area there was only one location where a noise barrier could be considered, and that was in the central reserve of a section of the road with two carriageways. Traffic speeds were too low to consider quieter surfacing options.




Reflective Barrier – central res. 80 - 1.5 120






13.39 An 80m long barrier was tested in 0.5m increments from 1.5m to 4m. 60 properties were

considered near this barrier location. The greatest reductions in noise were in the 1 to 2.9dB category, experienced at the properties closest to the centre of the barrier. Barriers of 2m or less in height were shown to have little effect on the noise levels. Barriers were most effective with a height of at least 3m. The introduction of a reflective barrier to the central reserve resulted in some increases in noise less than 1dB due to additional reflections.

13.40 When the barrier is at least 3m in height the reduction in noise offered by the barrier begins to cancel out the increases in noise due to the reflections. None of the options tested gave rise to acoustic benefits valued higher than the cost of the measure.

Case study 5

13.41 This case study was broken down into two areas, one at the north extent of the area of interest and one at the south extent. The motorway runs broadly north-south through the area. Both study areas consist primarily of two storey residential housing to the east of the carriageway.

13.42 For the first area, the carriageway is located in a shallow cutting. The mitigation options have tested introducing a noise barrier to the east of the carriageway at the top of the cutting slope. 134 properties were considered.

13.43 For the second area, parts of the carriageway are located in a shallow cutting. The mitigation options tested introducing low noise surfacing to the carriageways. This area includes an existing noise barrier to the east side of the carriageway. 45 properties were considered.

13.44 For the barrier tests, various heights were tested between 1.5m and 4m in height. Each successive increase in height resulted in greater acoustic benefits; however the cost increment of the barrier with each height increase was greater than the increase in acoustic benefits.


Reflective Barrier – NE 392 - 1.5 588









Resurfacing – both carriageways 200 15 - 3000

Resurfacing – both carriageways 500 15 - 7500

13.45 For the re-surfacing tests, two different extents of quieter road surface were tested. Each extent gave rise to broadly the same acoustic results, demonstrating that surfacing options should be limited to the area where they have greatest effect. None of the options tested gave rise to acoustic benefits valued higher than the cost of the measure.

Case study 6a

13.46 This study area consists of a predominantly at grade section of carriageway, with a grade separated junction at the eastern extent of the study area. South-west of this junction, and south of the section of carriageway of interest, is a predominantly residential housing estate.

13.47 The mitigation options have looked at introducing a noise barrier along the carriageway edge, up to where the carriageway meets the junction. 283 properties were considered.








13.48 As the location is near a grade separated junction, the effects of noise barriers are limited by the different slip roads and other roads in the area. Barriers were tested from 1.5m to 4m in 0.5m steps, and each height increment gave better reductions in noise at properties close to the main road and behind the barrier.

13.49 At the eastern end of the barrier, the other roads begin to have a more significant contribution to the noise levels, and the barrier becomes less effective.



Case study 6b

13.50 This study area consists of a section of carriageway that varies between being at grade and being in a slight cutting. North of the section of carriageway of interest, is a predominantly residential housing estate.

13.51 The mitigation options have looked at introducing a noise barrier along the carriageway edge, introducing quieter road surfacing and combining both quieter road surfacing and barrier mitigation. 80 properties were considered. This road is the dominant noise source at all noise sensitive receivers. The barrier tested was just under 500m in length, stretching the extent of the housing area. Heights were tested between 1.5m and 4m in 0.5m increments. Resurfacing was considered for just over 500m of carriageway.








Resurfacing – EB 555 8.4 - 4746

Resurfacing – WB 555 8.4 - 4746

13.52 For each increase in barrier height the acoustic benefits were greater, and in this situation decreases in noise of at least 1dB were achievable at almost all of the properties. However, the cost of the barrier exceeded the monetary value of the acoustic benefits for all options.

13.53 The resurfacing option gave decreases in noise at all properties; however the cost of the resurfacing exceeded the monetary value of the acoustic benefits.

13.54 The barrier and resurfacing options have been tested in combination; however the total cost of the measures exceeds the monetary value of the acoustic benefit.

13.55 Overall, the greatest reductions in noise come from a barrier in combination with resurfacing, but the solution with the best value for money is resurfacing.

Case study 7

13.56 This study area consists of a section of at grade carriageway in a town in an area including other roads. South of the section of carriageway of interest, is a predominantly residential housing area. This housing area is flanked to the east and west by other, more minor, roads.



13.57 The mitigation options have looked at introducing a noise barrier along the main carriageway edge. 257 properties were considered. In the study area considered, there were only a limited number of potential barrier locations due to access requirements.


Reflective Barrier – South East 158 - 2.0 316



13.58 Barrier heights of 2m, 3m and 4m were tested, giving benefit to some 60 to 65 properties. Traffic speeds were too low to consider quieter road surfacing. In each case, the increased barrier height gave rise to an improved barrier performance. In this case study the best value for money occurs with the 4m barrier option.

Case study 8

13.59 This study area is in a more rural area near a village, and the road begins as a single carriageway, and changes to a dual carriageway mid way through the area. The tests were undertaken on the single carriageway section of the road, and traffic speeds were too low to consider surfacing options. In the area selected there are groups of properties with access from side roads, allowing noise barrier options to run along the carriageway to the rear of their gardens.

13.60 The houses in the area are generally detached, with large gardens, and a group of 7 properties was considered. Barrier heights of 1.5m, 3m and 4m were tested for barriers on one side of the road, and reflective and absorbent barriers were tested.





Absorbent Barrier 270 - 1.5 405



13.61 The reflective barriers gave rise to increases in noise between 1dB and 3dB at the properties on the opposite side of the road from the barrier, and these reflections were eliminated with the absorbent barrier. Each height increment on the barrier gave better acoustic benefits for the



properties behind the barrier. In all situations, the cost of the barrier was greater than the monetary value of the acoustic benefit.

Case study 9

13.62 This study area consists of a section of elevated dual carriageway and some surrounding roads. Northeast of the section of carriageway of interest, is a predominantly residential housing area. This housing area is flanked to the north and east by other, more minor, roads. The nearest properties are set back some 100m from the road, and there is open grassland between the carriageway and the properties.

13.63 The mitigation options have looked at introducing a noise barrier of varying heights and lengths along the main carriageway edge. The options extend an existing noise barrier. 53 properties were considered. Two lengths of barrier were considered – a length of 340m and a length of 580m. Each length tested was set at heights from 1.5m to 4m in 0.5m increments. Traffic speeds were too low to consider a quieter road surfacing option.














13.64 The longer barrier length gave better results than the shorter barrier length. Over the barrier options, the 1.5m high 580m long barrier gives the best value for money.



Case study 10

13.65 This case study considered a single carriageway road through a small town. In the study area considered, there was only one potential location for a noise barrier, at the edge of the carriageway near the edge of the town where properties did not require access to the main road through the town. Traffic speeds were too low for surfacing options. A small group of 10 properties was considered. Barrier heights of 2m and 4m were tested.




13.66 The inclusion of the barrier gave rise to increases in noise smaller than 1 dB on the opposite side of the road from the barrier. The 4m barrier gave better acoustic benefits than the 2m barrier. Overall, the 2m barrier gives better value for money than the 4m barrier.

Case study 11

13.67 This case study considers a single carriageway road through a town/suburban area. The case study was broken down into two areas, one to the east of the carriageway of interest and one at the west of the carriageway of interest. Both areas consist primarily of two storey residential housing adjacent to the carriageway.

13.68 For the area to the east of the carriageway of interest, the ground from the carriageway falls away towards the properties, so that the carriageway position is in effect elevated compared with these properties. The mitigation options have looked at introducing a noise barrier of varying height and length to side of the carriageway. 103 properties were considered.

13.69 For the area to the west of the carriageway of interest, the ground rises from the carriageway towards the properties, so that the positions of the properties are in effect elevated compared with the carriageway. The mitigation options have looked at introducing a noise barrier of varying height to the west of the carriageway. 73 properties were considered.

13.70 In both areas, barrier heights from 1.5m to 4m were considered, in 0.5m increments, and the barrier length tests were undertaken at 1.5m and 4m heights. The results show that the barriers



are more effective at reducing noise levels when the ground falls away from the road, and are less effective when the ground rises from the road.


Reflective Barrier – east 280 - 1.5 420






Reflective Barrier – west 178 - 1.5 267












13.71 Each height increment gave incrementally more reductions in noise, although for this case study, the benefits of raising the barrier where the ground rises gave smaller benefits. The summary tables show no difference between 3.5m and 4m, although there is a small improvement in the monetary value of the acoustic benefits.

13.72 Given that the barriers to the east were more effective than the barriers to the west, the tallest and shortest options were tested to identify what the effect would be with a shorter barrier, and this length was reduced in ~80m lengths.

13.73 In all cases, the cost of the mitigation is higher than the value of the acoustic benefits. Overall, for this case study, barriers smaller than 3m gave the best value for money. This case study was also used to test traffic management options, which is reported at the end of this chapter.



Case study 12

13.74 This case study area predominantly consists of three story terraced housing on both sides of the track. Some properties have balconies overlooking the railway. The track is in a cutting, and properties on both sides of the track have been considered, 16 in a terrace on one side, and 20 in a terrace on the other. Only the properties which directly overlook the track have been considered.

13.75 Short lengths of barrier have been considered on both sides of the track, with 180m on one side and 150m on the other, on both sides this was positioned at the top of the cutting. Barrier increments of 0.5m between 1.5m and 3m have been considered, and the results have been compared for both the “high speed” option – which includes diesel locomotives on full power, and the “low speed” option – which does not include any diesel locomotives on full power.










13.76 At a 1.5m barrier height, the difference in attenuation offered by the high speed and low speed scenarios can be seen clearly, and the barrier is much more effective for the low speed scenario where all the sources are at the wheel/rail interface. The differences are smaller when the barriers are 3m tall, and there is a reduction in noise of at least 3dB at all properties.

Case study 13



13.77 This study area is predominantly two storey semi-detached housing. Some properties were identified to have loft conversions. The track in this location is in a cutting, and the positioning of noise barriers at the top of the cutting has been tested. The study area includes 63 properties, 35 to the south and 27 to the north. Only properties directly facing the track were considered. Barriers were tested installing on the south of the track, protecting the 35 properties. Tests were undertaken with reflective and absorbent barriers.





Absorptive Barrier 350 - 2.0 700



13.78 Because the track is in a cutting, including a noise barrier at 2m height gave rise to large reductions in noise, and increasing this to 3m and 4m gave further improvements over this.

13.79 When reflective barriers were considered, there were negligible increases in noise at the properties on the opposite side of the track. Absorbent barriers were also tested, and these negligible increases were removed. In this case study the negligible increases were insufficient to affect the valuation.

Case study 14

13.80 This case study considers an elevated section of railway line running north-south through an urban area. The area is mixed residential and non-residential use, and the study area considers 167 residential properties to the west of the railway line, which are generally 3, 4 and 5 storeys, with upper floors overlooking the railway. The study area also includes a small number of two storey properties. Some of the buildings in the study area are flats, and there is more than one dwelling in these buildings. There are 8 tracks on this section of line.

13.81 The case study considers a range of barrier options 330m long on the west side of the railway from 1.5m to 4m in 0.5m increments. As the buildings on the other side of the railway are non- residential, only reflective barriers have been considered. Both the high speed and low speed scenarios have been considered.










13.82 Because of the overall width of the line there is little difference in the reductions in noise offered between the high speed and low speed options because the difference in barrier attenuation for the furthest tracks is small. In this situation the benefits for the higher speed line trains gain a greater monetary value than the lower speed lines as the total noise levels for these trains is higher than the lower speed lines.

Case study 15

13.83 This study area includes 4 to 5 storey apartment blocks, and multi-storey town housing to the south of the railway line, with five tower blocks each with 20 floors, and a large number of 4 to 8 storey residential apartment blocks, all to the north of the railway line.

13.84 The mitigation options have looked at introducing a noise barrier to the south of the railway line, and also introducing noise barriers to both sides of the railway line. 2060 properties were considered. The railway line is four tracks wide, and is broadly at grade in this area.






13.85 In certain areas houses may have been converted to flats. However the case study has assumed that such areas remain as houses, and the property counts have been assigned to the top floor.

13.86 The results show that the barriers in this area are less effective for the high-speed scenario, with the elevated source height, are more effective for the slow speed scenario with the lower source height.

13.87 The lower barrier heights actually give rise to an acoustic dis-benefit because the reflective barriers give rise to more increases in noise than decreases in noise.



Traffic Management Case Study

13.88 In order to consider some of the alternative noise control measures identified, it was decided to use case study 11 to investigate the consequences of using traffic management options to reduce noise levels at a particular location. Roadside noise barriers have been tested in this area, and these are reported above.

13.89 The data for this case study included access to the underlying traffic model which was used for the scheme which the case study was based on. In addition to the barrier options considered to reduce noise, a range of traffic management options were tested using the traffic model to identify the potential reductions in noise and to establish the potential overall costs and benefits from such measures. One section of one of the routes through the area was selected in the area where the noise barrier tests reported above were undertaken, and three traffic management options were tested:

• Implement a 20mph speed limit (the road has a 30mph limit currently);

• Implement a ban on heavy goods vehicles;

• Close this section of road completely.

13.90 For each case study, the following steps were undertaken:

• Use the underlying SATURN traffic model to establish the changes in traffic on the road network just after the measure has been implemented;

• Analyse this traffic data to establish the change in noise due to the measure, and monetise the value of any changes in noise;

• Estimate the costs of implementing the measure;

• For the complete closure option the output of the SATURN traffic model was also used to establish the costs to the economy using the COBA software, described in the DMRB.

Description of traffic model

13.91 The traffic model used covers a group of communities outside the suburbs of a major city, and the main route through the communities provides a connection between two arterial routes out of the city. The traffic model includes this link through the communities, and the local road network in the vicinity. Either side of the route though the area is undulating countryside, and there are only limited country lanes offering wider traffic diversion away from this route. The area is shown in the following figure with the main routes in pink and green, and local routes in black. The location of the section of road where the traffic management options have been considered is shown with the blue square.



Figure 13.1 – Traffic study area

13.92 The traffic model includes five possible alternative routes through the communities, and all possible traffic routes through the area have been examined to identify the potential effects of the traffic management options. A line which bisects all possible routes has been identified (referred to as a screen line), so that the total traffic passing through the area for each option can be compared. The following figure shows the screen line in blue.

Figure 13.2 – Traffic screen line



Traffic Modelling Results

13.93 The total traffic on all routes crossing the screen line was used as a sensitivity test to establish that the traffic model was giving appropriate results. The results of the sensitivity tests are shown in the following table:

Table 13.4 – Screen Line Comparison Tests for the Sensitivity Tests

2010 Do Nothing

2010 HGV Ban 2010 20mph Link

2010 Link Closure

PCU Flow 37628 37867 37638 37950

Change from 2010 Do Nothing

N/A +240 +11 +322

13.94 The results of the screen line comparison demonstrate that there is no significant variation in the volume of modelled total flow across the screen line between the different scenarios. These variations are due to the effect of double counting but represent less than 1% of the total flow.

20mph speed limit scenario:

13.95 The results of the 20mph speed restriction on the selected section of the main route are demonstrated in Table 13.5 below.

Table 13.5 - PCU Flows on selected links for the 20mph Speed Limit Sensitivity Test

Link Road 2010 Do Nothing (PCU Flows)

2010 With 20mph Speed Restriction (PCU Flows)

Change

Alternative 1 6943 7000 +57

Alternative 2 5084 4995 -90


Main Route 19202 19335 +132

Alternative 4 2403 2223 -179


Total 37628 37638 +11

13.96 The results in Table 13.5 above show that there is a limited impact forecast arising from the restriction to the speed limit on the Main Route. Contrary to expectations there is a marginal increase in traffic on the Main Route. This would appear to be due to the Main Route receiving an extra 2 seconds of green time at a signalised junction at one end of the 20mph limit, induced by the new speed restriction.

HGV Ban

13.97 The results of the HGV Ban on the selected section of the main route are demonstrated in Table 13.6 below.



Table 13.6 – PCU Flows on selected links for the HGV Ban Sensitivity Test


2010 With HGV Ban (PCU Flows)

Change

Alternative 1 6943 6885 -57

Alternative 2 5084 6226 +1142

Alternative 3 1536 1944 +408

Main Route 19202 14193 -5009

Alternative 4 2403 5732 +3330

Alternative 5 2460 2886 +426

Total 37628 37867 +240

13.98 The results show that reassignment of trips from the Main Route is forecast to occur as a result of the HGV ban in place. As expected, most of the reassignment is confined to Alternative 2 and Alternative 4. However, the number of reassigned PCUs is greater than the 6% (1152) of HGVs on the link. Therefore, it appears that some light vehicles are also reassigned from the Main Route to alternative routes.

13.99 Further analysis shows that as a result of banning HGVs to the Main Route, there is an increase in delay at the junction at one end of the HGV ban, caused by eastbound traffic making opposed right turns and causing additional delay to this junction. This in turn results in the reassignment of light vehicles from the Main Route to other routes as well as the banned HGVs.

13.100 This delay and subsequent reassignment of HGV and Light vehicles is a result of the SATURN Signal Optimisation process. As HGV movements on the Main Route at this junction are routed to/from the side arms, the optimisation process provides the side arms with a greater amount of green time through the junction as part of the reassignment process.

13.101 This results in a reduction of green time for the Main Route of around 26%, thus reducing the number of vehicles on the Main Route by approximately 26%.

Route Closure

13.102 As a result of the Road Closure of the selected section of the Main Route there is a significant reassignment of trips forecast on the network. Table 13.7 below demonstrates a summary of the changes in traffic flows across the network.

Table 13.7 - PCU Flows on selected links for the Link Closure Sensitivity Test


2010 With Link Closure (PCU Flows)

Change

Alternative 1 6943 8464 +1522

Alternative 2 5084 12045 +6960

Alternative 3 1536 3964 +2428

Main Route 19202 0 -19202

Alternative 4 2403 8629 +6226

Alternative 5 2460 4848 +2388

Total 37628 37950 +322



13.103 The forecast implications of the Main Route closure are significant with an increase of 6960 and 6226 vehicle PCUs on Alternatives 2 and 4 respectively.

13.104 Furthermore, moderate increases are also evident on Alternatives 1, 3 and 5, thus demonstrating that there is strategic reassignment forecast as a result of closing the section of the Main Route.

Traffic Summary

13.105 The sensitivity tests as outlined above have been modelled using the SATURN traffic modelling software. The screen line test demonstrates that the modelled scenarios do not significantly alter the total number of vehicles across the screen line.

13.106 The Table 13.8 summarises the traffic impact of the three proposed scenarios on the 2010 Do Nothing model.

Table 13.8 – Summary of the Impact of the Sensitivity Tests

2010 20mph Speed Restriction

2010 HGV Ban 2010 A473 Link Closure

Level of impact No impact Slight Significant

13.107 The following points can be made following the sensitivity tests:

• The 20mph speed restriction on the short length of the Main Route has no significant impact on the route assignments within the network.

• The results of the 2010 HGV ban on the same section of the main route had a slightly greater impact than would be expected, with some light vehicles reassigned on to alternative routes as result of the increased movements on the side arms, and therefore increase in delay to the main road traffic at a junction on the main route.

• The full closure of the same section of the Main Route is forecast to have a significant impact on the local assignments and demonstrates a moderate impact on the wider strategic movements within the model.

Effects on Noise Levels

13.108 The output of the traffic model for each of the scenarios has been put into the noise model which was used for the project upon which this case study is determined. The noise model was modified to ensure that the tests being undertaken for this project were being captured appropriately.

13.109 The three options were calculated along with the do-minimum option, using the procedures in CRTN. The DfT TAG monetisation spreadsheet was used to calculate the monetary value of the changes in noise. This monetisation assumed that the current year was 2009, and the measure was installed in 2010, correlating with the traffic model. It was assumed that there would be no changes in traffic or noise after the opening year.

13.110 The results of the monetisation is shown in the following table.

Table 13.9 – Summary of Monetisation and Annoyance Results

20mph Restriction

HGV Ban Road Closure

Net Present Value of Noise Proposal £71,459 -£1,992,121 -£5,216,347

Estimated Population Annoyed (Without Scheme) 1740.3 1740.3 1740.3

Estimated Population Annoyed (With Scheme) 1739.9 1801.6 1901.4

Change in number of people annoyed. 0 61 161



The Affected Section of the Main Route

13.111 The 20 mph speed restriction option does not result in a perceptible reduction in noise on the affected section. In the Do Nothing scenario the speed on the affected section is not significantly above 20mph, and the new speed limit does not alter traffic speeds sufficiently to generate a perceptible reduction in noise.

13.112 In the HGV ban and road closure options there are perceptible reductions in noise predicted on the affected section of the Main Route.

The Surrounding Road Network

13.113 For the 20mph restriction option there were no perceptible changes in noise on any links of the road network.

13.114 The HGV ban option results in a perceptible reduction in noise levels on the affected section of the main route and several adjoining links of that route. The banned HGVs are re-routed by way of alternative routes, where there are predicted to be perceptible increases in noise levels, due to the increase in the proportion of heavy vehicles and the associated overall increase in traffic flow. These alternative routes all pass through or near residential areas and therefore the predicted increases in noise impact upon a large number of people.

13.115 The road closure option results in similar noise impacts to those predicted for the %HGV ban option, however the impacts extend further over the road network and are generally of a greater magnitude. The impacts are predominantly due to the redirection of traffic on to alternative routes to bypass the closed section of the main route. These alternative routes all pass through or near residential areas and therefore the predicted increases in noise impact upon a large number of people.

13.116 Therefore, for this case study, the effects of the traffic management options which give rise to benefits in the selected area actually give rise to greater disbenefits in the wider area.

Costs of Measures

13.117 The costs of the measures have been estimated on the basis of the information in Chapter 7, as follows.

• 20mph limit: Four pairs of speed limit signs @ £2000, replaced every 10 years, and four speed cushions @ £600, replaced every 5 years

• HGV Ban: Single cost of £9000, measures replaced every 10 years

• Closure: One off cost of £12,000, effectively the closure of two junctions.

For each option, an allowance of 50% has been added for design and other costs. These have been assessed over a 60 year appraisal period.

Table 13.10 – Summary of Costs

Measure Initial Cost of Measure Economic Cost of Measure

20mph Speed Limit £15,600 £56.515

HGV Ban £13,500 £40,907

Junction Closure £18,000 £18,000



Economic Assessment

13.118 An economic evaluation for the option where the section of the main route was completely closed has also been undertaken in accordance with advice and guidance in Design Manual for Roads and Bridges (DMRB) Volume 13.

13.119 Two scenarios were tested using the COBA model - these are:

• 2010 Do Nothing – Using the Do Minimum network, representative of the existing situation.

• 2010 Do Something – Using the same Do Minimum network, minus the section of road selected for closure.

Methodology

13.120 The SATURN traffic model outputs described above were used as input to a COBA model. The following steps were taken:

2010 Do Nothing

• Step 1 - The 2010 Do Minimum morning and afternoon peak hour flows and inter-peak flows were extracted from the SATURN model. These flows were disaggregated by vehicle type so that the proportion of Light and Heavy vehicles could be represented on each link.

• Step 2 - The extracted flows were expanded to generate 12 hour equivalent flows, which were then factored up using historical ATC data from the local area to generate 24 hour AADT flows.

• Step 3 – The summation of directional flows on each link was undertaken forming 2 way AADT flows.

• Step 4 – The 2 way AADT flows were input to the COBA model.

2010 Do Something (With Link Closure)

• Step 1 - The link closure was coded into the SATURN model and the trip assignments were performed to provide traffic flow with the selected link closed.

• Step 2 - The 2010 Do Something morning and afternoon peak hour flows and inter-peak flows were extracted from the existing SATURN model. These flows were disaggregated by vehicle type so that the proportion of Light and Heavy vehicles could be represented on each link.

• Step 3 - The extracted flows were expanded to generate 12 hour equivalent flows, which were then factored up using historical ATC data from the local area to generate 24 hour AADT flows.

• Step 4 – The summation of directional flows on each link was undertaken forming 2 way AADT flows.

• Step 5 – The 2 way AADT flows were input to the COBA model.

COBA coding

13.121 The coding of the COBA model has been carried out to reflect the impact of the link closure on the wider highway network contained within the COBA model.

13.122 The assessment has involved omitting any operational benefits arising from the deletion of the selected link and the consequential foreshortening of the Do Something network relative to the Do Minimum, as to do so would result in unrealistic benefits being ascribed to the Do Something test network.



Results

13.123 The main points to emerge from the analysis are as follows:

13.124 Converting costs into Market Prices gives a Present Value of Benefits of -£34,863,000.

13.125 This means that the closure of the selected section of the main route would impose costs on road users of approximately £35 million. The monetary value referred to here is in 2002 prices and has been discounted to the Present Value Year of 2002 over an assessment period of 60 years.

Traffic Management Case Study Summary

13.126 Three traffic management options have been considered to control noise levels using the traffic model used for one of the case studies. The following table summarises the costs and benefits of each option:

Table 13.11 – Summary of Traffic Management Case Study

Option Change in Noise?

NPV Noise Cost of Measure

Economic Cost

20mph limit No perceptible change

+£71k -£57k Not assessed

HGV Ban Perceptible reduction

-£1,992k -£41k Not assessed

Complete Closure

Perceptible reduction

-£5,216k -£18k -£34,863k

13.127 This assessment has shown that for the single case study tested, the treatment of noise problems by the use of traffic management measures is difficult. Where a measure is shown to give rise to benefits in one area, it is also shown to give rise to larger noise and economic disbenefits in the wider area, and these effects are further compounded by the costs of implementing the measure. In this particular case study the alternative routes are limited to a fairly narrow corridor, and the effects of re-routing traffic give rise to increases in noise.

Summary of Case Study Analyses

Road surfacing measures

13.128 On the majority of case studies selected, the traffic speeds were too low to consider the user of a quieter road surface as a noise control option. This measure is therefore likely to only potentially apply to motorways and dual carriageways. All single carriageways in urban and suburban areas are likely to be excluded from this type of measure straight away unless a revised calculation method is determined which considers changes in noise from road surfaces at speeds below 75kph.

13.129 Road surfacing measures improve the noise levels at all locations where the noise from that road is dominant, and effects can be perceived at greater distances in the road outside of urban areas.

Barrier Measures - Road

13.130 Noise barriers are difficult to implement in urban areas, except on motorways and dual carriageways, as access is often required to get onto the road. In the case studies selected which considered urban, suburban and town areas, there were limited opportunities for locating barriers which did not obstruct access. Whilst a suitable barrier location was identified in each case study, this may not be of the case for a particular noise management area identified by the strategic noise maps.



13.131 Although taller barriers tend to offer the greatest reductions in noise, these may not offer the best cost effectiveness, particularly for shorter lengths of barrier protecting a small number of properties. Several iterations of barrier design may be required to optimise the barrier design.

13.132 Barriers are not effective at tall buildings close to roads or railways, and their acoustic performance depends on the distance between the road and the building. For shorter barriers (up to around 2m in height), properties above the 10th floor are unlikely to get changes in noise greater than 1dB. When the barrier is taller (approximately 4m) changes in noise of 1dB can be experienced at properties up to approximately the 20th floor, although there were no buildings greater than 20 storeys in the case studies. In some circumstances, changes in noise were experienced at lower floors than indicated, particularly when the buildings were set back from the source.

13.133 If the building is screened from the source, either by a cutting or a noise barrier, then the potential reductions in noise offered by a barrier would be limited, and floors above the 6th floor are unlikely to receive changes in noise greater than 1dB.

Barrier Measures – Rail

13.134 As the rail infrastructure is often within a fenced corridor, it is much more feasible to consider controlling railway noise by the use of barriers either alongside the track or at the railway boundary.

13.135 As for road traffic, while taller barriers tend to offer the greatest reductions in noise, these may not offer the best cost effectiveness, particularly for shorter lengths of barrier protecting a small number of properties.

Traffic Management Measures

13.136 The results of a single case study with selected traffic management measures showed negative economic impacts. It is not possible to draw general conclusions about using traffic management measures to control noise from this single case study, and it is also not possible to identify what type of location or traffic management option may give rise to an overall benefit from such a measure.

Sensitivity Testing

13.137 A number of sensitivity tests have been tested to explore simplifications and assumptions which could be made. The first set of tests has been to look at the monetised value for some of the case studies, and see how the valuation varies if small changes in noise are ignored, and if properties with lower noise levels are ignored. The analysis has been undertaken based on the DfT TAG spreadsheet in 3dB noise bands. The second set of sensitivity tests looked at the distances from the sources where different changes in noise could be experienced, in order to inform the selection of the study area.

Ignoring small changes in noise

13.138 Typically, if changes in noise less than 1dB are ignored, the monetisation is within approximately 90% of the equivalent monetisation for all properties (i.e. including changes smaller than 1dB); however the variability may be higher if the monetisation is undertaken using 1dB bands rather than 3dB bands.

13.139 If changes less than 3dB are ignored, then the monetisation breaks down, particularly where road surfacing measures are being considered. Noise barriers and road surfaces can give improvements between 1dB and 3dB at high numbers of properties.

13.140 This test shows that the areas of case studies need to include all properties where changes in noise of at least 1dB are experienced. Changes in noise less than 1dB do not have a significant effect on the monetisation of noise levels and these changes can be ignored.



Ignoring lower noise levels

13.141 On the whole, the case studies were focussed on areas where noise levels were above 60dB. However for some case studies, noise levels were typically below 60dB from the roads and railways under consideration, and generally in order to include changes in noise down to 1dB, some properties with lower noise levels have been included for the majority of case studies.

13.142 Noise levels in the successive 3dB bands in the TAG spreadsheet have been ignored, to examine the sensitivity of the valuation to the exclusion of lower noise levels.

13.143 Where the case study has a high number of properties with noise levels above 60dB, ignoring noise levels below 54dB has little effect on the valuation, reducing it by a maximum of a few percent. In certain circumstances if noise levels below 57dB or 60dB are ignored, then the monetisation can be reduced by a larger amount, demonstrating that significant changes in noise are not being considered.

13.144 This test shows that where changes in noise are being experienced at lower noise levels, calculations need to be included out to approximately 55dB to ensure that any such benefits are included in the valuation.

Ignoring small changes in noise and lower noise levels

13.145 The two tests described above were combined, and the successive removal of lower noise levels had similar effects when changes less than 1dB and 3dB were ignored. The combination of the two tests shows that extending the study area to include changes greater than 1dB is more important than limiting the calculations to properties above a certain noise level.

13.146 Changes in noise greater than 1dB could be ignored where noise levels are below 55dB, as the valuation of changes in noise at all such locations does not contribute significantly to the overall valuation.

Distances for 1dB Changes

13.147 To establish an upper bound for the size of study areas, the case studies with the larger barriers and extents of noise control were examined. The study area should include all locations where the change in noise is expected to be at least 1dB, although this becomes less important when noise levels are below 55dB.

13.148 The effectiveness of noise control measures is often limited by the presence of other noise sources which provide a significant contribution. The largest study area would be required for elevated roads in rural areas. In this situation a 4m barrier at the road side could give changes in noise at a distance of some 600 to 800m from the road, provided that there were no other noise sources.

13.149 Generally speaking, the case studies showed that if the study area extended some 400m from the noise control measure, then changes in noise of at least 1dB would typically be within this distance.

13.150 In practice, the study may be able to be curtailed further if there are other noise sources closer than this, but if the traffic flows on the other road or railway are significantly lower than the road or railway being controlled, it should be demonstrated that there are no changes in noise levels at properties further back.


13.151 For first floor locations, where there are no other noise sources contributing, barriers of 2m in height may give improvements of 3dB or more at distances up to around 100m, although this distance may be reduced in the presence of additional screening affecting the location. If the height of the barrier is increased to 4m, then improvements of 3dB or more can be realised at



distances of up to around 200m, although this distance may be reduced in the presence of additional screening affecting the location.


13.152 With a 4m barrier in place it is possible to get improvements at first floor locations which exceed 5dB, but these are usually restricted to locations less than some 50 to 100m behind the barrier.

Significance of measures

13.153 There are no clear patterns about the numbers of properties with reductions in noise which cause the monetary value of the acoustic benefits, other than to note the following general observations:

• The greater the reduction in noise, the greater the monetised benefits.

• The greater number of properties with reductions, the greater the monetised benefits.

• Reductions from higher noise levels give greater monetised benefits than equivalent reductions from lower noise levels.

13.154 However, noise control measures were included in the case studies for very small groups of properties where the monetised values of the acoustic benefits were greater than the cost of the measures, indicating that in some situations it is possible to provide very localised mitigation which can be cost effective.

13.155 Clearly, some situations are easier to provide mitigation for than others, and it is difficult to consider anything other than a building improvement envelope measure in other situations.

Chapter Summary

13.156 This chapter has described the case studies that have been investigated, including the basis for their selection and the analyses undertaken. The concluding findings from the case studies are presented.



14. Conclusions

14.1 This project has reviewed methods for assessing and valuing the costs and benefits of noise control measures for road traffic noise and railway noise. An assessment approach has been defined which allows such noise control measures to be assessed and compared in a consistent way.

Noise Control Measures

14.2 Methods have been given for predicting, assessing and comparing changes in noise from the following noise control measures:

• Noise barriers;



• Traffic management options;

• Building improvement measures.

14.3 The prediction methods are generally based on the nationally approved calculation methodologies Calculation of Road Traffic Noise and Calculation of Railway noise, although the advice given could equally be applied to any other calculation methodology.

Valuation

14.4 The Department for Transports Transport Analysis Guidance method for valuing the changes in noise at residential properties is the Government’s approved method for valuing changes in noise due to road and railway schemes. This report extends the use of this method to consider changes in noise due to noise control measures, and has highlighted some shortcomings in this application of the method.

14.5 There is no method available to value to acoustic benefits of measures to improve the acoustic performance of a building envelope. Further research is required in this area if consideration of building envelope improvements is to be considered alongside other forms of noise control in cost benefit analyses.

14.6 A method has been determined for valuing noise impacts in amenity spaces, however this method relates to quieter noise levels, and may not be appropriate for amenity spaces with high noise levels. No methods for valuing noise impacts at non-residential buildings were identified in the literature review.

Assessment Approach

14.7 The step by step approach to assessing noise control measures provides scoping tools to allow noise control measures to be excluded from further consideration at an early stage in the assessment, and other types of assessment which may be required have been identified, which may further limit the types of noise control measure being considered.

14.8 Noise levels at residential properties below 55dB LAeq have been shown to only contribute a small amount to the valuation of impacts from noise control measures, and such receptors can be excluded from consideration.

14.9 It is important that all changes in noise level of at least 1dB are considered in the assessment, particularly at the higher noise levels where these may influence the valuation. Selection of the study area and inclusion of all changes in noise of at least 1dB is critical in ensuring the acoustic benefits are quantified accurately.



Further work

14.10 During the research undertaken for this project there were a number of areas where further research may be required to confirm certain elements of this work, including:

Sensitivity of Results

14.11 Further research is required to confirm appropriate significance criteria for changes in noise at non residential locations.

Noise Control Measures: Road Surfacing

14.12 The CRTN procedures and latest advice in the DMRB assign improvements to noise levels when traffic speeds are above 75kph. The literature identifies that some benefits may be perceived below this speed, and this could be included in the assessment methodology once such improvements have been researched.

Noise Control Measures: Building Envelope

14.13 The papers reviewed identify that trickle ventilators can degrade the performance of double glazed windows. Research could identify if there are methods of improving the performance of these windows in situ where an alternative provision for ventilation has been made.

Noise Control Measures: Traffic Management

14.14 Consideration of further case studies would be required to understand the practicalities of this type of measure.

Costs of Measures

14.15 Robust costs or unit values need to be established for noise control measures to use in the earlier stages of the assessment, when measures are being compared before detailed design has been undertaken. Costs are similarly required for the design, planning, implementation and maintenance phases of the noise control measure.

Valuation: Building Envelope

14.16 Research is required to establish a valuation method which considers the acoustic benefits offered by building envelope measures.

Valuation: Non-residential Locations

14.17 Research is required to determine a method for valuing the changes in noise at non-residential locations.

Valuation: Health vs. Annoyance

14.18 Economists assume that people are perfectly well informed and act rationally. Therefore when people purchase a house it is assumed that they are aware of the noise levels and corresponding effects. Therefore the hedonic pricing method may include the willingness to pay for all consequences of noise, including health and annoyance effects.

14.19 Given that the research on health effects is reasonably recent, this complete knowledge may not hold. Research would be required to identify if it is possible to treat these two valuations separately or if there would be an element of double counting if the two valuations were summed together.

Full Cost Benefit Analysis Spreadsheet

14.20 It would be possible to derive a spreadsheet implementation of the costs and benefits elements of the toolkit described above which could be useful for allowing a consistent approach to assessing noise control measures, particularly in the early stages of an assessment.



15. References

1 The Green Paper on Future Noise Policy (COM(96) 540) ,1996

2 Directive 2002/49/EC of the European Parliament and of the Council of 25 June 2002 relating to the assessment and management of environmental noise

3 Good Practice Guide for Strategic Noise Mapping and the Production of Associated Data on Noise Exposure , Position Paper by European Commission Working Group Assessment of Exposure to Noise (WG-AEN), Version 2, 13 August 2007

4 The Environmental Noise (England) Regulations 2006, Statutory Instrument 2006 No. 2238 5 The Environmental Noise (England) (Amendment) Regulations 2009, Statutory Instrument

2009 No. 1610 6 The Environmental Noise (Wales) Regulations 2006, Welsh Statutory Instrument 2006 No.

2629 (W.225) 7 The Environmental Noise (Scotland) Regulations 2006, Scottish Statutory Instrument 2006

No. 465 8 The Environmental Noise Regulations (Northern Ireland) 2006, Statutory Rule 2006 No.

387 9 Draft Noise Action Plan, Major Roads Template (outside first round agglomerations),

DEFRA, March 2009 10 Draft Noise Action Plan, Major Railways Template (outside first round agglomerations),

DEFRA, March 2009 11 Draft Noise Action Plan, Agglomeration Template, DEFRA, March 2009 12 Draft Noise Action Plan Major Roads (outside first round agglomerations) Public

consultation on Draft Noise Action Plans, DEFRA, July 2009 13 Draft Noise Action Plan Major Railways (outside first round agglomerations) Public

consultation on Draft Noise Action Plans, DEFRA, July 2009 14 Draft Noise Action Agglomeration Template Public consultation on Draft Noise Action

Plans, DEFRA, July 2009 15 Strategic Noise Action Plan for the Glasgow Agglomeration, Scottish Executive, 2009 16 Strategic Noise Action Plan for the Edinburgh Agglomeration, Scottish Executive, 2009 17 Transportation Noise Action Plan, Scottish Executive, 2009 18 Environmental Noise Action Planning (Wales), Swansea/Neath Port Talbot Agglomeration

Action Plan, WAG, 2009 19 Environmental Noise Action Planning (Wales), Cardiff and the Vale of Glamorgan

Agglomeration Action Plan, WAG, 2009 20 Environmental Noise Action Planning (Wales), Roads Action Plan for Wales, WAG, 2009 21 Environmental Noise Action Planning (Wales), Railway Action Plan for Wales, WAG, 2009 22 Draft Northern Ireland Environmental Noise Directive Action Plan, NI DOE, 2008 23 Guidelines for Community Noise, World Health Organisation (WHO) 1999



24 An Economic Valuation of Noise Pollution – developing a tool for policy appraisal. First

report of the Interdepartmental Group on Costs and Benefits, Noise Subject Group, Defra, August 2008

25 Developing Harmonised European Approaches for Transport Costing (HEATCO) and Project Assessment, All project deliverables. See also, references 52 and 57.

26 The Association between noise exposure and blood pressure and ischemic heart disease: a meta-analysis, Van Kempen EE, Kruize H, Boshuizen HC, Ameling CB, Staatsen BA, de Hollander AE, Environmental Health Perspectives, Volume 110, March 2002

27 Transport Noise and Cardiovascular Risk – Review and Synthesis of Epidemiological

Studies – Dose-effect Curve and Risk Estimation by Dr. Wolfbang Babish, Federal Environmental Agency, January 2006

28 Office for National Statistics; Dataset ST341122 – Noise complaints received by Environmental Health Officers, Dataset from 2001/2001 last updated 2004.

29 Impacts of highways on Dutch breeding birds: An analysis by applying national bird censuses, R. Cuperus and R. Foppen, 2003 International Conference on Ecology and Transportation, August 2003

30 Noise, Health and Money – The Price of Noise 2008, The theme group Noise MSR 2008,

Milieumonitoring Stadsregio Rotterdam, June 2008 31 Social inequality and noise pollution by traffic in the living environment--an analysis by the

German Federal Health Survey, Hoffman, B., Robra B.P. and Swart E., PubMed, Jun; 65(6):393-401, 2003

32 The Noise Insulation (Amendment) Regulations 1988, Statutory Instrument 1988 No. 2000,

November 1988

33 The Noise Insulation (Railways and Other Guided Transport Systems) Regulations 1996, Statutory Instrument 1996 No. 428, February 1996

34 Building Bulletin 93 Acoustic Design of Schools, Department for Education and Skills, 2003 35 Design Manual for Roads and Bridges, Volume 11 Environmental Assessment, Section 3

Environmental Assessment Techniques, Part 7 HA 213/08 Noise and Vibration, Highways Agency, August 2008

36 Interim Advice Note 125/09 Supplementary guidance for users of DMRB Volume 11 ‘Environmental Assessment’, Highways Agency October 2009

37 Design Manual for Roads and Bridges, Volume 11 Environmental Assessment, Section 2 Environmental Impact Assessment, Part 5 HA 205/08 Assessment and Management of Environmental Effects, Highways Agency, August 2008

38 Area Management Memorandum 43, Guidance on the noise reducing measures at locations meeting the ‘Hansard’ criteria – Covering categories 2,3 and 4, Highways Agency, December 2003.

39 Transport Appraisal Guidance. Unit 3.5.4 Cost Benefit Analysis, DfT, February 2006

40 Transport Appraisal Guidance. Unit 3.3.2 The Noise sub-objective, DfT, November 2006

41 Waardering van Natuur, Water en Bodem in Maatschappelijke Kosten-batenanalyses, Aanvulling op de Leidraad OEI, ECM Ruijgrok, December 2004

42 Rail and wheel roughness - implications for noise mapping based on the Calculation of

Railway Noise procedure, A report produced for Defra by AEJ Hardy and RRK Jones, AEATR-PC&E-2003-002, March 2004



43 BS EN ISO 3095: 2005, Railway Applications – Acoustics – Measurement of noise emitted by railbound vehicles

44 EffNoise; Service contract relating to the effectiveness of noise mitigation measures, Final Report, Lärmkontor, Hamburg, 2004

45 Calculation of Railway Noise, DoT 1995 (amended 1996) 46 Calculation of Road Traffic Noise, DoT/Welsh Office, 1988 47 Review of Studies on External Costs of Noise prepared by Rhian Hawkins, Environment

Protection Economics Division DETR July 1999 48 Valuation of Noise, Position Paper of the Working Group on Health and Socio-Economic

Aspects, 4 December 2003 49 Developing Harmonised European Approaches for Transport Costing and Project

Assessment (HEATCO), Deliverable 4, Economic values for key impacts valued in the stated preference surveys, Navrud et al, February 2006

50 Noise valuation in ex-ante evaluations of major road and railroad projects, European Journal of Transport and Infrastructure Research Issue 8, Hans Nijland and Bert van Wee, September 2008

51 Benefits of Noise Measures, Jabben J, Potma C, Lutter S, National Institute of Public Health and Environment (RIVM), Netherlands, RIVM Report 680300002, October 2007

52 The Dutch national Guideline for the Valuation of Nature, Water and Soil in cost benefit analysis, Ruijgrok. E.C.M, Brouwer, R., Verbruggen, H, Ministry of Transportation and Waterworks, Ministry of Economic Affairs and the Ministry of Agriculture, Nature and Food Quality, The Hague, Netherlands, December 2004.

53 Practicitioner Handbook for Local Noise Action Plans: Recommendations from the SILENCE project, Sixth Framework Programme, European Commission

54 Developing Harmonised European Approaches for Transport Costing and Project Assessment (HEATCO), Deliverable 1, Volume 1 (main text), Current practice in project appraisal in Europe, Analysis of country reports, Thomas Odgaard (COWI), Charlotte Kelly (ITS) and James Laird (ITS) with contributions from partners, January 2005

55 Quantifying burden of disease related to environmental noise: Second technical meeting

report, WHO Europe, Bern, Switzerland, 15-16 December 2005

56 Experts consultation on methods of quantifying burden of disease related to environmental noise: First Technical Meeting, State Health Agency of Baden-Württemberg, Stuttgart, Germany, 23–24 June 2005

57 Estimating dose-response relationships between noise exposure and human health

impacts in the UK, Berry Environmental Ltd, July 2009

58 The Valuation of Transport-Related Noise in Birmingham, Non-Technical Report to the DfT, Bateman I. J, Day B. H. and Lake I, 4th September 2004

59 Developing Guidance on the Valuation of Transport-Related Noise for Inclusion in WebTAG, Paper presented to the Seminar ‘Valuing Transport Related Noise’ held at the Department for Transport, London, 17th May 2005, Nellthorp, J, Bristow, A. and Mackie, P,

60 Transport Appraisal Guidance. Unit 3.3.2 The Noise sub-objective, DfT , Supplementary Guidance: Valuation of Transport-Related Residential Noise, www.dft.gov.uk/webtag/documents/expert/doc/unit3.3.2-supplementaryguidance.doc



61 ANASE, Attitudes to Noise from Aviation Sources in England, Final Report for Department for Transport in association with John Bates Services, Ian Flindell and RPS, October 2007

62 Unification of accounts and marginal costs for Transport Efficiency (UNITE), Funded by the European Commission 5th Framework – Transport RTD, Final Report for Publication, by Chris Nash with contributions from partners, November 2003

63 Transport Appraisal Guidance. Unit 3.3 The Environment Objective, DfT

64 Transport Appraisal Guidance. Unit 3.4 The Safety Objective, DfT.

65 Transport Appraisal Guidance. Unit 3.5 The Ecomony Objective, DfT

66 Transport Appraisal Guidance. Unit 3.6 The Accessibility Objective, DfT

67 Transport Appraisal Guidance. Unit 3.7 The Integration Objective, DfT

68 Transport Appraisal Guidance. Unit 3.1.2 Transport Models, DfT, June 2005

69 Transport Appraisal Guidance. Unit 3.5.6 The Values of Time and Operating Costs, DfT, April 2009

70 Transport Appraisal Guidance. Unit 2.7.2 Appraisal Summary Table, DfT, February 2004

71 Town and Country Planning Act 1990

72 The Town and Country Planning (General Permitted Development) Order 1995, Statutory Instrument 1995 No. 418

73 The Green Book, Appraisal and Evaluation in Central Government, Treasury Guidance,

London



Appendix A - Further

Initiatives Relevant to Action Plans



A.1 Introduction

A.1.1 This Appendix considers some of the further initiatives relevant to action planning and cost- effectiveness of noise control measures.

A.2 Strategic Noise Mapping

A.2.1 In accordance with the END, the Member States are required to define the noise calculation methods to be used for the first round of strategic noise maps. Some, for example England, France and Denmark, used national methods adapted to the requirements of the directive. Others, in particular those without existing national methods, are planning or have chosen the interim methods, adapted in accordance with the European Commission’s recommendation 2003/613/EC – “guidelines on the revised interim computation methods for industrial noise, aircraft noise, road traffic noise and railway noise”.

A.2.2 As the strategic noise maps are based on a standard calculation method, being able to use these to demonstrate the benefits of particular noise control measures or to identify noise management areas can be constrained by the limitations of the calculation methodology. If subsequent rounds of strategic noise mapping use a different calculation methodology, these may change the selection of noise management areas or the ability to demonstrate noise control measures.

Strategic Mapping Guidelines

A.2.3 In December 2003, the European Commission Working Group Assessment of Exposure to Noise (WG-AEN) produced a Position Paper entitled the Good Practice Guide (GPG) for Strategic Noise Mapping and the Production of Associated Data on Noise Exposure, and this was updated by GPG version 2 in January 2006. The document describes general issues and specific technical challenges raised by the directive covering both strategic noise maps and mapping, and the creation of Action Plans.

A.2.4 GPG v2 has 21 toolkits of solutions relating to specific challenges (for example, the determination of traffic flow data). These toolkits describe procedures / tools that have been evaluated in relation to cost, accuracy and complexity and presented using a simple pictogram code.

Pan-European Calculation Methods

A.2.5 One important project is the Harmonoise project to develop a new, common, pan-European noise- mapping calculation method. The Directive gives the European Commission the right to implement a common pan-European calculation method for the 2012 round of mapping.

A.2.6 The Harmonoise project (Aug 2001 - Jan 2005) produced methods for the prediction of environmental noise levels caused by road and railway traffic. These methods were intended to become the harmonized methods for noise mapping in all EU Member States. Noise levels are predicted in terms of Lden and Lnight, which are the harmonized noise indicators according to the END.

A.2.7 The European project ‘IMAGINE’ followed on from the Harmonoise project and has developed new calculation methods for railway, road, industrial and aircraft noise. IMAGINE will standardise the Harmonoise methods and will provide practical guidelines, good practice and harmonised data management for the production and exploitation of strategic noise mapping and noise Action Plans (e.g. traffic flow management) in the EC according to the requirements and recommendations of the END.

Mapping Requirements

A.2.8 Strategic noise maps will need to be prepared to show the Lden and Lnight of each type of source (road, rail, industry, etc.) at a height of 4m over the ground.



A.2.9 Aggregation of levels from different sources can be performed with a stated method. The European Union requires the making of maps of transportation and industrial noise using current models that comply with certain demands. The following methods are recommended although well-established national methods can be used until an agreed harmonised method is introduced:

• Roads: NMPB-96 (the French method)

• Railways: RLM2 (the Dutch method)

• Airports: ECAC 29

• Industrial sites: ISO 9613.

A.2.10 The general public must be consulted during the process, and the European Environment Agency in Copenhagen will collate the results in a central European database.

A.2.11 The first maps for major areas were required by mid 2007. This activity is repeated at five yearly intervals and all defined areas are to be incorporated in the second and subsequent iterations. These are the minimum requirements and some countries are expected to go further and faster.

A.3 UK National Ambient Noise Strategy

A.3.1 In December 2001, the Government published a Consultation Paper74 entitled ‘Towards a National Ambient Noise Strategy’, fulfilling a commitment in its 2000 Rural White Paper75 to develop such a strategy.

A.3.2 The Consultation Paper stressed that the objective of the exercise is to develop a National Ambient Noise Strategy. The other main objective of the exercise is to set a context for noise mapping that will have to be undertaken to fulfil the requirements of the European Environmental Noise Directive.

A.3.3 The consultation paper stated that in Phase 1 of the Ambient Noise Strategy (2002-2005) the aim was to establish:

• The ambient noise climate in this country. In simple terms, the number of people affected by different levels of noise, the source of that noise (i.e. road, rail, airports and industry) and the location of the people affected. Noise mapping, as required by the EU Directive, would be one of the main tools used for this phase.

• The adverse effects of ambient noise, particularly regarding people's quality of life. Special consideration will also be needed in regard to tranquillity.

• The techniques available to take action to improve the situation where it is bad or to preserve it where it is good.

• The methodology to be used to undertake economic analysis.

A.3.4 In Phase 2 of the Ambient Noise Strategy (2004-2006) it is aimed to evaluate and prioritise options for actions identified in Phase 1 in terms of the costs and benefits including the synergies and conflicts with other Government priorities, such as other environmental, economic and social issues.

A.3.5 In Phase 3 of the Ambient Noise Strategy (2007), the Government will need to agree on the necessary policies to move towards the desired outcome and the completion of the National Ambient Noise Strategy. Revisions of the strategy can then be envisaged on a five yearly cycle.

A.3.6 Legislation is likely to be needed in due course to place duties upon the various parties involved to undertake the necessary actions such as to:

• provide the necessary input data;

• carry out mapping exercises;



• maintain maps;

• produce Action Plans; and then supply the results in appropriate formats.

Roads and Road Traffic Noise

A.3.7 Actions suggested addressing noise from vehicles and roads include; type approval for the noise requirements for new vehicles, roadworthiness inspections and exhaust checks in MOT, controls on lorry rattle and ancillary equipment noise, action on existing road hotspots, quiet road surfaces in the 10 year transportation plan.

Rail

A.3.8 Actions suggested to address noise from railways include; an enhanced programme of rail- grinding and inter-operability agreements across Europe.

Aviation

A.3.9 Actions suggested to address noise from aviation include; departure noise limits, departure noise preferential routes and night flight restrictions.

Cost Benefit Analysis

A.3.10 It was highlighted that during phase 2 of the strategy it is important to look at balancing the costs of reducing noise exposure with the benefits. There might also be wider positive or negative impacts on society which may need to be taken account of.

A.4 Mayor of London’s Ambient Noise Strategy

A.4.1 The Mayor of London’s Ambient Noise Strategy (LANS), Sounder City, was published in March 2004 following widespread public consultation. It sets out a comprehensive agenda aimed at securing support for minimising noise and improving soundscape quality across London. It is the first citywide strategy of its kind in the UK. It is thought that this should act as a pilot for the national ambient noise strategy.

A.4.2 As a national ambient noise strategy is prepared, along with development of noise mapping and action planning, there will be both needs and opportunities to establish priorities that will be acoustically effective, administratively deliverable and affordable. The Mayor is keen to play his part in this process, in partnership with central government, boroughs and other parties. In the short term, implementation has to remain flexible in relation to changes in the context for action.

A.4.3 The policies and proposals included within the LANS generally favour following a ‘source- pathway-receptor’ sequence for minimising traffic noise on London’s streets. It is recognised that the relative importance of each measure may vary depending on local circumstances. The relevant factors may be ease of implementation, responsibility or cost-effectiveness. The noise control measures are considered under the following headings:

• Quieter vehicles;

• Traffic reduction, street space allocation and routeing;

• Quieter, smoother and safer driving;

• Better street works and street maintenance;

• Noise-reducing road surfaces;

• Tree planting, noise barriers, landform and highway structures;

• Spatial planning and urban design;

• Building insulation;

• Neighbourhoods, town centres, public spaces, walking and cycling.



A.4.4 There exist extensive links between the Mayor’s Ambient Noise and Transport Strategies. As such, it is not possible to view noise issues separate from safety, sustainability, economic and other environmental considerations.

A.5 Traffic Noise Action Programme (TNAP)

A.5.1 The Mayor’s London Ambient Noise Strategy (2004) placed a responsibility on TfL to take action on noise along its road network. As a result the Traffic Noise Action Programme (TNAP) was developed for the Transport for London Road Network (TLRN).

A.5.2 The project included recommendations for further work. In order to get a better idea of the cost of typical noise control measures in London, it was proposed that ‘demonstration projects’ were used. It was suggested that Network Management teams might look at the detailed noise plans to identify noise clusters within their area of interest, and then to study these in more detail including specific mitigation measures and a cost-benefit analysis.

A.6 London Boroughs

Unitary Development Plans (UDPs)

A.6.1 In accordance with the Town and Country Planning Act 1990 all London Borough Councils must produce a Unitary Development Plan (UDP). The UDPs set out the local authorities’ policies and proposals for the development and use of land in its area. UDPs follow the procedures laid down in the Town and Country Planning (Development Plan) Regulations 1991 (as amended) and the guidance given in Planning Policy Guidance Note 12 (PPG 12).

A.6.2 UDPs are not site specific, other than on the Proposals Map and contain policies which aim to reduce impacts across the whole borough rather than a local area. The UDPs do not directly control proposals for individual developments.

Supplementary Planning Guidance (SPGs)

A.6.3 In addition to the UDPs, many other London Borough Councils also produce a Supplementary Planning Guidance (SPG). These guidance documents are not statutory but provide guidance on how to use various polices described within the adopted UDP. SPGs expand on UDP advice, sometimes reiterating what has already been stated. However SPGs can go further for example, in the case of noise, to describe mitigation methods that may be used in order to increase chances of obtaining planning permission in noisy areas.

A.7 Regional Noise Strategies and Initiatives

A.7.1 There are a number of regional initiatives’ currently underway to tackle the problem of environmental noise.

Merseyside

A.7.2 A noise study was undertaken around Merseyside starting April 2003 and taking 12 months to complete. It involved noise measurement and noise modeling, but the key aim of the study was to undertake a survey of public opinions and attitudes towards noise.

A.7.3 The findings of the study provide a justification for development of a Merseyside Environmental Noise Strategy, irrespective of the forthcoming obligations under the implementation of the END.

A.7.4 The Merseyside authorities identified that the development of an Environmental Noise Strategy/Noise Action Plan would be pioneering work within the UK and it is likely that the development of a Merseyside Environmental Noise Strategy and Noise Action Plan would need to be staged over 3-4 years. It would require a firm commitment from all partner authorities and a working relationship with Defra. As transportation noise, particularly road traffic noise is the key



noise source on Merseyside, the plan would benefit from being developed in conjunction with the Local Transport Plan.

Birmingham

A.7.5 Birmingham City Council let a contract in March 1998 to undertake data collection and modelling to produce noise maps (Sound Immission Contour Maps – SICMs) of the City of Birmingham. The aim of the Birmingham study was to produce a ‘state of the art’ product using modern computer aided calculation. The maps should show the sound levels outside all buildings in Birmingham with as much resolution and accuracy as possible. The maps were produced for separate daytime (0700 – 2300) and night-time (2300 – 0700) maps were to be produced using the LAeq,T noise indicator with a contour bandwidth of 5 dB.

A.7.6 Birmingham CC has not gone on to draw up a local Noise Strategy or Action Plan based on the results of this mapping study, but are looking at some measures and costs for addressing the 1% of the noisiest buildings in the city.

Bristol Citizenscape Project

A.7.7 Following on from the production of a noise map for the Bristol agglomeration, Bristol City Council are consulting the public during 2009 on how environmental noise affects individuals, and giving them opportunity to influence how the noise Action Plan might be implemented in Bristol. This is part of an EU funded project called Citizenscape.

A.7.8 The project asks for thoughts on measures including planning to help reduce traffic noise and protect quiet public spaces, managing traffic congestion, quieter road surfaces and cycling initiatives. Focusing mostly on road traffic noise the council also emphasise what individuals can do to reduce noise emissions by choosing quiet tyres, Eco driving, using other forms of public transport and supporting campaigns for lower speed limits.

A.8 Highways Agency Hotspots Noise Assessments

A.8.1 The Highways Agency (HA) has an established methodology (described in HA’s Area Management Memo No 43) to deal with some of the most serious and pressing cases of noise pollution from the trunk road network. The cases were listed in Hansard in 1999 in response to a parliamentary question. It is more commonly known as a ‘Hotspot Noise Assessment’.

Hotspot Noise Assessment Methodology

A.8.2 This intervention programme is consistent and fully auditable to demonstrate HA’s effective use of a ring-fenced annual budget of £5M for providing appropriate noise mitigation measures. A brief overview is given below as an example of how it is done in the UK at the moment.

A.8.3 An initial ‘sift assessment’ is carried out using a number of well established ‘sift criteria’ as detailed below:

a) The road must have been opened or altered before June 1988 and

b) The noise level immediately adjacent to the road and calculated from current traffic data must be at least 80 dB LA10,18h and

c) In the case of roads opened or altered after October 1969, the calculated roadside noise level must be at least 3 dB greater than was predicted for the design year

A.8.4 The cases which meet the sift criteria are carried forward for a detailed ‘six-stage process’:

• Stage 1 identifies the number of properties potentially affected by the section of road under consideration.

• Stage 2 investigates the presence of features already in place which mitigate the effects of noise.



• Stage 3 estimates the noise levels in accordance with Calculation of Road Traffic Noise (CRTN).

• Stage 4 uses a ‘Noise Severity Index’ to rank the ‘severity’ of problem in terms of nuisance. The nuisance calculations are based on a relationship given in DMRB Volume 11/3/7 and take into account the number of properties per kilometre of road at which the noise levels are likely to be found annoying. According to the severity of the problem, different cases are prioritised into 4 different ‘Categories’ (1 to 4) and further into 5 levels of ‘priority ranking’ (1 to 5). All category 1 locations are accorded first priority for noise reduction measures. Locations in other categories are given a ranking according to their Noise Severity Index.

• Stage 5 ranks the potential benefits of different levels of action which could reduce noise levels by varying degrees, for example:

- Sufficient to reduce exposures by the noise exceedance assessed under sift criterion (c) (see above).

- A significant reduction (at least 2 dB) at worst affected properties

- Sufficient to ensure no property exposed to more than 75 dB(A)

- Sufficient to ensure no property exposed to more than 72 dB(A)

- Sufficient to ensure no property exposed to more than 68 dB(A).

• Stage 6 estimates the costs of mitigation measures compared with notional costs of insulating affected properties.

Review of the Scheme

A.8.5 An investigation was undertaken into the effectiveness of the above HA ‘Hansard’ noise mitigation programme by undertaking an assessment of noise levels and a social survey before and after noise mitigation measures at a sample of the noise hotspot sites, and control locations76.

A.8.6 At each of the sites included in the study, detailed acoustical data were acquired at several measurement locations for several weeks both before and after mitigation measures, together with corresponding meteorological and traffic data. Additional satellite measurements allowed allocation of noise levels to individual dwellings affected by the mitigation scheme.

A.8.7 As part of the study a survey of residents’ attitudes was carried out both before and after mitigation measures, using a structured questionnaire specifically designed for this study. The questionnaire examined their feelings about living in the area, including their attitudes to noise (not only traffic noise) and to other road traffic nuisance.

A.8.8 The second survey, after noise mitigation work had been completed, usually took place about a year after the first. Researchers were instructed to ensure that the same person was interviewed on each occasion, and the ‘before’ and ‘after’ questionnaires were matched, so that changes in responses could be analysed.

A.8.9 All sites where mitigation work had taken place showed significant decreases in at least one noise indicator. For the control sites, a much smaller number of significant changes were seen, and the majority of these were increases in noise level.

A.8.10 At the sites examined in this study, the results indicate that both barriers and surface overlays were associated with significant reductions in measured noise, and significant improvements in subjective ratings of noise levels.

A.8.11 The HA hotspot noise assessment methodology is a good example of a cost-effectiveness assessment of noise remediation measures in the UK and its robustness has been demonstrated by social surveys.



74 ‘Towards a National Ambient Noise Strategy’, DEFRA, 2001 75 ’Our Countryside: the future, A fair deal for rural England’, DETR, November 2000 76 Mitigation of noise hotspots on existing roads - final report by BRE for Highways Agency,

February 2005



Appendix B - Noise Control

Measures



B.1 Introduction

B.1.1 The aim of this appendix is to provide a review of various types of noise mitigation measures, focussing in particular on actions against road traffic noise and railway noise including light rail systems such as trams.

B.1.2 There are various mitigation measures which could be applicable to road and rail related noise sources. Some of these have been highlighted in the Draft Action Plans for England published in March 2009 (major roads, major railways and agglomerations)9,10,11. Practical guidance and advice would be required, both at policy level and Local Authority level.

B.1.3 The objective of this review is to identify on a consistent basis noise remediation strategies which could be considered with the approach described in the main report text. Some of the strategies outlined in this review are well researched and established, and are included in the main text of this report. Other strategies would require further research before they could be similarly included.

B.1.4 The discussions of various noise remediation strategies are structured under the following sub- headings

• Strategy identification;

• Background;

• Acoustic benefits;

• How to model or calculate benefits;

• Other considerations.

B.1.5 The discussion provides an indication on the time period likely to be required for the various measures to be effective following their implementation (penetration) and the minimum geographical extent for the noise strategy to be effective (implementation area) as well as the noise source to which the mitigation measure would be applicable. The generic noise mitigation classifications used are listed below:

a) Measures at noise source;

b) Measures affecting operation of traffic;

c) Measures affecting noise propagation;

d) Measures at noise-sensitive receiver;

e) Economic and social regulating methods;

B.1.6 The information on applicability, penetration, implementation area and classification is summarised for each remediation measure at the beginning of relevant section in the following format.



Mitigation Strategy Information Descriptions

Applicability – the noise sources to which the strategy relates to

Road

Rail

Penetration - time period required for the strategy to be effective following its implementation

Short Term – immediate effect

Medium Term – some transition period required for effectiveness

Long Term – significant time period required for effectiveness

Implementation area - minimum geographical extent for strategy to be effective

Local – discrete sections of network

Regional/ City – wider extent of network

National – across UK

International – across EU

Classification – type of strategy Measures at noise source

Measures affecting operation of traffic

Measures affecting noise propagation

Measures at noise-sensitive receiver

Economic and social regulating methods

Table B.1 – Strategy Identification

B.1.7 Using this approach, the applicability of noise remediation strategies to the Local Authority context or Government Policy level has been identified. For example, mitigation measures which require implementation across the UK or EU to be effective would not be applicable for the local context. This helped the identification of the potential case studies in the project.



B.2 Noise Remediation Measures

B.2.1 The specific noise control techniques which could be used for controlling road and rail traffic related noise sources are given below for each mitigation classification.

Measures at noise source

• Quiet road vehicles including power train and tyre noise;

• Low-noise heavy goods vehicles;

• Road surfaces;

• Railway and train maintenance;

• Rail rolling stock design;

• Streetworks and street maintenance.

Measures affecting operation of traffic

• Altering traffic flow and imposing vehicle restrictions;

• Traffic calming and speed limits;

• Smooth driving.

Measures affecting noise propagation

• Noise barriers;

• Vegetation.

Measures at noise-sensitive receiver

• Land use planning and management;

• Building design.

Economic and Social Regulating Methods

B.2.2 There are inevitable overlaps between various classifications. For example measures affecting the operation of traffic would also affect noise generation at source. A reduction in traffic volumes may need to be achieved as part of a wider policy of encouraging a shift from road transport onto alternative and quieter modes of transport. Measures to achieve smooth flows may need to incorporate interventions along the road network with appropriate driver training initiatives to raise awareness of the influence of driving styles on noise.

B.2.3 Further details are given in the following sections for each of these measures.



B.3 Quiet Vehicles – Power Train and Tyre Noise

Strategy Identification


Applicability Road

Penetration Long Term

Implementation area National &

International

Classification Measures at noise source

Background

B.3.1 The two main noise generating features in motor vehicles are the power train, which includes the engine and transmission, and the tyre/road interaction or ‘rolling noise’. Vehicle noise is dependent on the characteristics of the vehicle, the driving conditions and the characteristics of road surface. The effect of road surface on noise generation is discussed in later sections. This section considers the influence of power train and tyres on noise levels.

B.3.2 The relative importance of power train noise, which includes components such as engine, exhaust and transmission, and tyre/road noise depends on the type of vehicle and the way the vehicle is driven. Power train sources are primarily controlled by the vehicle engine speed and the use of gears whilst tyre/road noise is dependent on the vehicle’s road speed and the road surface type and condition.

B.3.3 For light vehicles such as passenger cars, power train source is dominant at low speeds in low gears, whereas at higher road speeds in top gear, tyre/road noise is likely to be the dominant source. For HGV vehicles the power train is the dominant source of noise under most operating conditions although at higher road speeds the tyre/road noise becomes significant.

B.3.4 The most important component of rolling noise is generated by the tyres rolling over the road surface77. The main factors affecting tyre noise are the speed of rotation of the tyre, the type of tread pattern and material, and the texture applied to the road surface. Rolling noise has a negligible contribution to the overall noise from heavy vehicles at low speeds. Above about 30 km/h for cars and 40 km/h for heavy vehicles, rolling noise becomes a significant part of the noise. Above 50 km/h, rolling noise is the dominant noise source for cars, and above 70 km/h for heavy vehicles.

B.3.5 In built-up area where the traffic speeds are already low, a reduction in power train noise would be essential for reductions in overall noise. However within the trunk road environment where traffic speeds are designed to be high, a reduction in rolling noise could be the main way of reducing overall noise levels. For some of the other roads, a combination of measures would be required. In order to achieve noise reduction across a wide area, both noise generation mechanisms would need to be tackled.

Acoustic Benefits

B.3.6 It has been shown that the component of vehicle noise which is due to tyres can be reduced by an appropriate choice of tyres78. A summary of findings is given below.

B.3.7 Using lower noise tyres it is possible to obtain substantial benefits of up to 5 dB LAeq especially on a relatively rough surface such as hot rolled asphalt.

B.3.8 There is a large range in noise levels obtained from different types of tyres. The range in levels for each of the main tyre categories is about 6 dB LAeq which represents a very large change in



noise from the noisiest to the quietest tyre. There could be some scope of reducing tyre noise limit values without compromising the road safety of the vehicles.

B.3.9 The benefits would be greater on hot rolled asphalt (HRA) than the smoother stone mastic asphalt (SMA) due to the greater dominance of rolling noise over propulsion noise on the rougher surface. On hot rolled asphalt the benefits above 35 km/h were shown to be 3 dB LAeq or greater, while on stone mastic asphalt this benefit is predicted to occur only above a speed of approximately 80 km/h. Unlike the situation for power train noise, the benefits of lower noise tyres are predicted to increase with road speed. However it is noted that in the UK, the Highways Agency no longer specify HRA and local authorities are favouring SMA or similar products.

B.3.10 With further advances in technology and vehicle legislation expected over time, it is likely that vehicles will become quieter over time and therefore a gradual decrease in noise from individual vehicles should be expected. The change to electric or other low noise propulsion units will take considerable time and as yet there is no prospect of an early change to this type of propulsion unit. Recent estimates put the percentage of electrically powered vehicles at about 10% in the year 2020. If all vehicles were refitted with electric drive units, noise benefits of 3 to 4 dB(A) could be expected at speeds less than 30kph.

B.3.11 The work undertaken by TRL78 explains that if all passenger cars were refitted with lower noise tyres, this might result in a 5dB reduction in rolling noise and a 3 dB reduction in overall traffic noise for a smooth road surface. However tests would need to be carried out on rougher surfaces to assess the benefits under current UK conditions.

How to model or calculate benefits

B.3.12 The implementation of a strategy based on the introduction of quieter vehicles into the traffic stream would not be directly possible to assess using CRTN. This model determines source noise levels from inputted values of the total flow, the composition of the traffic stream and the average speed of the traffic.

B.3.13 However the expected benefits could be converted into reductions in equivalent total traffic flow or applied as a road surface correction term in order to make use of strategic noise mapping for estimating area wide changes in noise exposure.

B.3.14 Alternative calculation methods (e.g. Harmonoise) could be used for estimating the likely benefits of this strategy.

Other Considerations

B.3.15 The noise emission characteristics of individual vehicles would be governed by the tyre noise limits and propulsion noise limits. The lowering of limits would depend on vehicle safety standards and the current state of technology.



B.4 Low Noise Heavy Goods Vehicles



Applicability Road


Implementation area National &

International


Background

B.4.1 In situations where the heavy vehicles make up a relatively small proportion of traffic, the effect of reducing noise from heavy vehicles alone would have limited effect on overall noise levels. However in certain situation where the number of heavy vehicle traffic is particularly high it would be desirable to consider less noisy alternatives. Examples are buses and freight vehicles on designated routes through residential areas and domestic waste collection vehicles at certain hours of the day.

B.4.2 The public fleet, including waste collection vehicles, public transport and all other vehicles used by the local authorities would need to be renewed at some point. This could provide an opportunity for selecting quieter vehicle types. The new vehicles could be concentrated in areas with the highest noise problems. Most local authorities now subcontract this work and therefore do not own or control the fleet and this could make it more difficult to achieve the desired noise targets in practice.

B.4.3 The main components of heavy vehicle noise comprise engine noise (travelling at low speeds and idling), operation of air brakes and venting. There may be other sources of noise such as exhausts, reversing bleepers, refrigeration units in some commercial vehicles, body noise including body rattle and suspension. Although some of these noise sources would not affect long term average noise levels, they are generally considered to be a potential source of nuisance.

Acoustic Benefits

B.4.4 A study undertaken by TRL79 has found that the noise levels associated with idling of the engines of heavy goods vehicles could vary by 15 dB(A). This noise can be intrusive so identifying vehicles with particularly high levels of noise when idling could be an important factor that could be used when granting operation permits in noise sensitive areas.

B.4.5 The study also found that noise from operating the air brakes and venting often produced noise levels significantly above the often quoted proposed limit value of 72 dB(A) for this source of noise. Fitting air brake silencers can help in reducing this source of noise and could therefore be a considered as a requirement when considering certifying vehicles for operations in noise sensitive areas.

B.4.6 Electric vehicles offer potential benefits for noise reduction. These come in a variety of forms including battery powered electric, hybrid electric and fuel cell powered vehicles. Currently fuel cell powered taxis and buses up to 18 tonnes are in service. In recent tests comparing a battery powered electric vehicle and the diesel equivalent it was found that the current type approval value was reduced by nearly 7 dB(A). The change was due to the significant reduction of the propulsion noise component of total vehicle noise.



B.4.7 There are few electric vehicles currently in use. However the merits of promoting their use could be considered especially in noise sensitive areas. There are concerns about tonal noise from large electric motors which may cause annoyance even at low levels.

B.4.8 A number of examples of the use of low noise heavy goods vehicles are described below53.

B.4.9 In many cities waste collection is carried out during evening or early morning hours in order to reduce congestion. New waste collection vehicles designed to reduce noise emissions can contribute significantly to lower noise levels.

B.4.10 The quiet waste collection vehicles combine engines working on gas, a hydraulic system for emptying the waste bins and pressing the waste inside the vehicle working on electricity from batteries, with an effective catalyst converter. A reduction of up to 25 dB(A) was observed

compared to conventional waste vehicles53.

B.4.11 Low noise electric powered delivery vehicles could be used to make local deliveries from a central delivery warehouse. Using low-noise vehicles and unloading equipment and training the staff for quiet operation can make the delivery quiet and more tolerable during the night.

B.4.12 Low-noise vehicles and unloading equipment (e.g. fork lifts) can be provided for by the shop owners or by the city. An example of this is the City of Vicenza, Italy, which organises a central warehouse where deliveries for single shops are compiled and then distributed with quiet vehicles.

B.4.13 Modern tram and bus vehicles in general emit much less noise than the older stock. Renewing the fleet therefore can significantly contribute to noise abatement. The local authorities could enter agreements with the transport operators to tackle the noise issues. In situations where the public transport is owned by the local authority, there could be appropriate noise criteria associated with the procurement of vehicles in tenders.

B.4.14 Those criteria could refer to the complete fleet, single vehicles or only to new vehicles and define requirements to be achieved in different time periods. Such requirements for buses are given for example as53: 3 years after signing the contract, 80% of the fleet must comply with the limit value of 77 dB(A); the other 20% must not exceed 80 dB(A). New vehicles must comply with the limit value of 77 dB(A). Buses running at night-time must comply with the 77 dB(A) limit. All vehicles must run with low-noise tyres.


B.4.15 The benefits of potentially replacing some of the current vehicle fleet with the quieter alternatives cannot be modelled using standard methodologies such as CRTN. This model determines source noise levels from inputted values of the total flow, the composition of the traffic stream and the average speed of the traffic.

B.4.16 However the expected benefits could be converted into reductions in equivalent total traffic flow or applied as a road surface correction term in order to make use of strategic noise mapping for estimating area wide changes in noise exposure.

B.4.17 Alternative calculation methods (e.g. Harmonoise) could be used for estimating the likely benefits of this strategy.


B.4.18 In general, modern vehicles are also of benefit in terms of air pollutant emissions, energy consumption and road safety. Reducing the share of HGV in general could improve air quality and road safety.



Aeq

B.5 Road surfaces



Applicability Road

Penetration Short Term – immediate effect

Implementation area Local – discrete sections of network


Background

B.5.1 The SILENCE subproject F on ‘Road Surfaces’80 gives background information on mechanisms of noise generation and types of surfaces as well as their acoustic performance.

B.5.2 Road surfaces influence the generation of noise by tyre/road interaction and the propagation of noise from the vehicle engine and transmission system. The relevant factors for noise emission are the texture of the surface, the texture pattern and the degree of porosity of the surface structure.

B.5.3 Low-noise road surfaces today are either thin layer surfaces or porous asphalts with one or two layers. Thin layers are different bituminous layers with a maximum thickness of 3 cm and a small aggregate size (4-8mm as maximum chipping size).

B.5.4 Porous asphalt has an open structure with about 20-25% air void. It was originally developed to improve road safety by draining surface water quickly and reducing splash-backs. The porous nature helps to absorb noise and the reduction in surface water run-off also means less noise is generated at source. These surfaces could also have an effect of reducing reverberant build-up of noise due to multiple reflections between high rise buildings situated close to roads. However these tend not to be used in the UK due to problems with maintenance when they were trialled at several locations. Also, the drainage systems would need to be modified in order to facilitate the use of porous asphalts.

Acoustic Benefits

B.5.5 Alternative quieter road surfaces are considered to be potentially the easiest and the most effective method of noise reduction. Up to 4 dB LAeq benefits could be achieved at speeds greater than 35 kph by switching to lower noise alternatives than Hot Rolled Asphalt (HRA). The benefits would depend on HGV composition78. Current assessment guidance takes a worst case, and assumes that the maximum reduction in noise is 3.5dB at traffic speeds greater than 75 kph35.

B.5.6 In motorways with relatively large HGV content, benefits were predicted to be greater than 3 dB LAeq. Compared to brushed concrete, benefits could be even greater. In confined spaces such as city canyons, the use of porous asphalt could be beneficial since it could reduce the reverberant build up of noise.

B.5.7 At 50 km/h a change from HRA to a lower noise surface will result in a reduction of approximately 3 dB(A). At 30 km/h this drops to 2 dB(A).

B.5.8 Porous road surfaces can reduce the total noise emitted by vehicles by, typically, 2 to 4 dB LAeq, when the surfaces are new77. Up to 5 dB L could be reached on high-speed roads. With

suitable refinement, greater reductions up to 6 to 7 dB LAeq may be technically possible. This improvement applies to most vehicle operating conditions, not just high speeds. In some countries (for instance the Netherlands and France), porous surfaces are already being laid as standard on a large proportion of the major road network. The presence of buildings close to the road can alter



the sound field and the effects of low noise surfaces on reducing overall traffic noise levels needs further evaluation.


B.5.9 The benefits of lower noise surfaces could be modelled by assuming a ‘correction factor’ for the relevant road segments. In instances where the noise benefits vary for different classes of vehicles, there may be a need to account for these effects separately.


B.5.10 As part of routine maintenance, existing road surfaces could be replaced by quieter alternatives.

B.5.11 There can be a number of disadvantages associated with these surfaces such as durability, cost and the expertise required to implement them. The safety issues such as the skid resistance and drainage of any new material must be taken into account before being used in a real situation.

B.5.12 For use in urban areas, the porous asphalt still shows significant disadvantages in terms of costs, durability, winter maintenance, ravelling caused by shear forces, drainage systems and difficult repair after trenching for pipes and cables and after accidents.

B.5.13 Recently, open textured porous road surfaces have been developed, which offer the advantages of good skidding resistance in wet weather and good noise reduction and sound absorption characteristics. Thus these surface types provide both safety and considerable reductions of not only tyre noise but also to some extent the power train noise.

B.5.14 The long-term durability is crucial, and not yet proved to be sufficient. Also, clogging can close the pores and the cleaning of the surfaces is expensive. Winter conditions are particularly rough. Especially in the Nordic Countries, icing of the pores may easily break the structure, and the use of studded winter tyres forms an additional wear factor. These factors can also affect the generation of noise. At present, considerable research effort is being devoted to improving the durability of this type of road surface

B.5.15 In most cases, low-noise surfaces reduce the rolling resistance, thus they might decrease fuel consumption as well.



B.6 Railway and Train Maintenance



Applicability Rail

Penetration Short Term

to

Long Term

Implementation area Local to

International


Background

B.6.1 At low speeds the power unit of a train and the auxiliary equipment on multiple units contribute significantly to noise generation from railways. At higher speeds the interaction of wheels and rail becomes the dominant source of noise.

B.6.2 The conditions of the surface of the rail and the tread of the wheel and in particular the wheel and rail roughness have a significant effect on noise from a train. Defects in the wheel tread such as flats (due to wheels sliding during braking), loss of portions of the wheel tread due to thermal or mechanical fatigue, various rail running surface defects, and points and crossing are also contributors to railway noise. Rail/ wheel noise can be reduced by controlling the roughness of both wheels and rails and by minimising the formation of wheel flats and rail corrugations.

B.6.3 Noise from modern railway and tram vehicles are generally quieter due to tighter limits in type testing standards imposed by EU directives relating to the application of Technical Standards for Interoperability.

Acoustic Benefits

B.6.4 The major component of train noise is caused by the interaction of the steel wheels and the steel rails, which generates sound by the vibration of wheels, rails and vehicle structure, track support and ground.

B.6.5 The following vibration generating mechanisms may occur as a result of rail/wheel interactions and improving the railway track and train vehicles could provide associated benefits81:

• The motions caused by track and wheel irregularities: corrugations on the rail and flats on the wheel as well as roughness on both the rail and wheel. These imperfections can raise the noise level by 10 to 20dB, regular maintenance in the form or rail grinding and wheel turning can significantly reduce noise levels generated by the wheel/rail interaction.

• The impact of wheel flanges against the rail.

• Sliding contact of wheel flanges resulting in flange squeal (control measure is to avoid tight radii of curvature, and lubrication).

• Vibration of the supporting structure.

B.6.6 Both wheel and rail roughness may be substantially reduced by the use of disc brakes rather than the more conventional wheel tread braking. The rail roughness (and corrugation) can be



controlled by routine grinding of the rails. Other methods include the employment of rail isolation techniques and in particular the use of stiffer rail pads.

B.6.7 The rail isolation could be in the form of resilient rail fasteners to aid damping in the rail and to decouple the rail from the support structure, and the use of ballast mats on bridge decks to limit vibration coupling to the bridge structure. In addition, enhancing the ground absorption between and beside the rails may further reduce the noise by a few decibels.

B.6.8 The mechanisms of noise generation are similar on the tramlines. The noise problems can be worse due to the number of points and crossings and tighter curves. The tracks tend to be on the street level and there is no natural absorption from the slabs. In addition, they can run closer to buildings. Floating slab tracks could be used to reduce ground-borne noise. These should be designed appropriately to ensure they don’t result in low-frequency rumbling noise radiated from the slab itself.

B.6.9 In addition to the routine operation of rail and tram vehicles, railways and tram depots could also be a source of noise annoyance. The likely sources of noise could include coupling noise, curve squeal, rolling noise, stationary diesel noise, fan electric loco, air pressure release, compressor noise, braking noise and noise of trains rolling through switches. The use of warning horns or whistles (newer stock) in depots can be particularly annoying with the proximity of residential areas. These noise sources may need to be treated in the same way as noise from industrial and commercial sources. Noise screening may be applicable to those noise sources which are fixed. The noises from some of the mobile activities can be minimised by better site management and work practices. The potential mitigation strategies would need to be determined on a case-by- case basis and would depend on which noise sources are dominant and where they are located relative to noise-sensitive receivers.


B.6.10 Free flowing traffic movements can be modelled using standard calculation methodologies such as CRN.

B.6.11 There are specialist applications such as TWINS (Track Wheel Interaction Noise Software) developed by British Rail and ISVR, which can model the complex interactions between the wheel, the track and the rail. This software uses analytical tools such as Finite Element Methods and Boundary Element Methods as the basis of its calculations.


B.6.12 Although the imperfections in the rails and wheels are one of the biggest contributors to rail noise, removing irregularities from the rails or wheels is not a permanent solution. Imperfections in the wheels cause irregularities in the rails and vice versa, as they wear each other out. As it is not feasible to replace all wheels and rails in one go, eventually the replacement rails and wheels will have imperfections and will need to be replaced again in the future.

B.6.13 Changes to the vehicles must not reduce the safety of the trains, whether that situations such as the breaking system or attachment to the rails.

B.6.14 Undertaking track maintenance on an operational railway can be disruptive. Any new measures introduced to the tracks and wheels must be durable and cost effective.

B.6.15 Measures such as improving the structures and curvature of the rails would be longer term solutions.



B.7 Rolling Stock Design



Applicability Rail


to

Long Term


International


Background

B.7.1 The fitting of skirts to vehicles has been considered as a means of reducing rail vehicle noise. Under frame rail vehicle noise is principally generated by the wheel and rail interface but noise also arises on many multiple units from underfloor mounted engines, traction motors and auxiliaries.

B.7.2 For the purpose of this commentary, it is assumed the any such skirts or covers would be of rigid construction fixed to vehicle sides or chassis and reach to just above rail level covering bogie frames and most of the wheel side.

B.7.3 The practicability and effectiveness of fitting side covers to rail vehicles would need to consider and allow for:

• Clearance from vehicle underframe equipment. Most rail vehicles are carried on bogies which have heavy and rigid outside frames and axle boxes. These are wider than the actual track and wheel gauge. Side skirts would need to provide sufficient clearance to allow for bogie and vehicle swing.

• Side skirts would need to allow for clearance of line side equipment. Many items of track and signalling equipment such as point motors, power connections, signal controls and line side telephones are located beneath vehicle floor level. Wider skirts fitted to the exterior of rail vehicles could foul such equipment. Platform edges and bridge girders might also foul.

• Key safety equipment for the operation of signal and line speed warnings including AWS, TPWS and ERTMS are partly carried externally under vehicle floors. Any additional barriers or skirts must be clear of and allow easy access to such equipment.

• Much equipment for the operation of rail vehicles is carried beneath the floor and needs to be easily accessible for routine maintenance or in the event of failure. Example are brake cylinders, pipework and fittings, engines and traction motors and air conditioning or heating equipment. Skirts would need to be designed to allow easy access or easy removal.

• In contrast to accessibility, skirts or any other equipment fitted to the exterior of rail vehicle must be securely fixed to ensure there is no possibility of detachment during train running. This is a vital aspect for safety approval but conflicts with a need for easy access.

• Any design of vehicle skirts must take into account the possible need for lineside vehicle attention in the event of train failure. Under floor equipment must again be easily accessible for safety, delay and operational reasons. On occasions, in the event of serious train failure, it



is necessary for a train bogie to be lifted and carried on a “rail skid” to move a seized vehicle. Any skirt design and noise effectiveness might be limited by such a requirement.


B.7.4 Where this measure is retro-fitted, the acoustic benefits would need to be determined by a series of pass-by noise measurements with and without the skirts fitted to establish a correction which can be applied to the rolling stock for this measure.

B.7.5 If the measure is fitted to new vehicles, the source term for these vehicles would need to be determined for inclusion in calculations.


B.7.6 Where new build vehicles are involved, cost of design, manufacture and fitting of vehicle skirts or noise measures would be absorbed within the total design and development costs. Costs of new rail vehicles will vary according to volume, market and design but normal heavy rail passenger vehicles would be in excess of £1m each and a locomotive £2m or £3 m.

B.7.7 Retro fitting of skirts to existing vehicles would require detailed design and vehicle approval for each class and type of rail vehicle. Different equipment for each vehicle type would need to be manufactured and then fitted to the vehicles concerned. The complexity of such fitting would vary from vehicle to vehicle and from diesel to electric power but a very broad estimate is assessed as £5,000 per vehicle.



B.8 Streetworks and street maintenance



Applicability Road


Implementation area Local


Background

B.8.1 Unevenness (pot-holes, cracks) and discontinuities (change in surface type) on a road surface has the potential to influence noise generation by vehicles travelling over the surface. These features in a surface could increase road/tyre generated noise as well as resulting in body rattle and suspension noise from the vehicles.

B.8.2 Regular road maintenance is the best way of avoiding these issues. Maintenance also applies to low-noise surfaces for ensuring the performance of these do not deteriorate over time.

Acoustic Benefits

B.8.3 Regarding unevenness and surface discontinuities, singularities like manhole covers, humps and bumps, as well as tram crossings are relevant. Within the SILENCE project, measurements were carried out using Statistical Pass-By tests and Controlled Pass-By tests to identify the effect of irregularities on the noise levels82. It was found that the difference in noise levels in dB L AFmax for:

• Smoothly textured and evenly built-in manhole covers in a speed range of 30 to 70 km/h is negligible (less than 1 dB(A));

• Roughly textured or unevenly built-in manhole covers in the same speed range is moderate (+ 3 dB(A));

• Modern even humps made of smooth concrete block stones with smooth ramps for a speed up to 40 km/h is negligible (less than 1 dB(A)) and for speeds between 40 and 50 km/h moderate (between 2 and 5 dB(A));

• Old uneven humps made of rough cobble stones or for severe bumps in a speed range of 30 to 50 km/h is high (8 to 10 dB(A))

• Tram crossings with an angle of less than 80° to the driving direction and with even surface in a speed range of 30 to 70 km/h is low (1-2 dB(A)) if in good condition, and moderate (2-5 dB(A)) if in bad condition;

• Tram crossings with an orientation perpendicular to the driving direction but even surface in a speed range of 30 to 70 km/h is high (5-9 dB(A));

• Tram crossings with uneven surface made of rough cobble stones in a speed range of 30 to 70 km/h is high (8-12 dB(A));

• Measurements have shown a 6 dB(A) increase at the kerbside as a passenger car travelled over rumble areas composed of pads of coarse textured surfacing.

B.8.4 Changes of road surface type may also introduce road surface profile irregularities. The most usual are a step up or step down at the interface between the surfaces. This can cause impulsive body rattle noise as vehicles traverse the irregularity. Measurements have shown that peak levels of noise can be over 10 dB(A) above the original level resulting in some cases in significant



disturbance to those living in the vicinity. In many cases heavy goods vehicles produce the loudest noises in these circumstances due to a variety of causes such as a poorly secured loads, loose body components, e.g. tail gates, lifting equipment and chains, and suspension noises.

B.8.5 The peak noise levels next to bridge joints or joints in concrete roads could increase by 10 to 15 dB(A) depending upon the quality of the joint. However the long term average noise levels may not be affected to the same extent. Bridge joints containing elastomers could eliminate such noise peaks when vehicles are passing over.


B.8.6 Standard calculation methods such as CRTN cannot account for the effects of poorly maintained surfaces or joints on the average noise levels.

B.8.7 The resulting effects and the potential benefits may need to be determined through measurements.


B.8.8 Maintenance of the roads is an ongoing process. Any works which would improve the noise generation characteristics of road surfaces could be built into the road maintenance programmes provided there is sufficient funding to do so.



B.9 Altering Traffic Flow and Imposing Vehicle Restrictions



Applicability Road

Penetration Short Term to

Medium Term


Regional/ City

Classification Measures affecting operation of traffic

Background

B.9.1 A reduction in road traffic noise can be achieved through a reduction in the volume of traffic and/ or a reduction in the composition of heavy goods vehicles. B.9.2

A range of measures are available for reducing traffic volumes:

• Giving priority to public transport and rerouting private vehicles onto existing less sensitive routes;

• Building by-passes to concentrate urban traffic on less sensitive routes;

• Banning through-traffic by signs or by cutting roads;

• Implementing low-emission zones (e.g. certain types of vehicles);

• Limited access zones (e.g. residents only).

B.9.3 Assuming no changes in traffic speeds or percentage heavy vehicle compositions, a reduction in traffic volumes of at least 25% is required for a small noise reduction of 1 dB(A). Most of these measures would have a limited effect on the traffic volumes and they should be considered in conjunction with other measures for effectiveness.

B.9.4 The composition of traffic can be altered by restrictions or complete bans on heavy goods vehicles:

• Using sensitive routes or areas

• During sensitive time periods (weekends, evenings, night-time).

B.9.5 This can be achieved through the use of designated freight routes between cities. Within the city boundaries, there could be a need for strategically located lorry parks to minimise unnecessary commercial vehicle activity around residential areas. The wear and maintenance implications of this on the designated route should be considered.

Acoustic Benefits

B.9.6 Changing the traffic volume affects the noise levels. Assuming the traffic composition, speed and driving patterns are unchanged, the logarithmic nature of the dB scale means that a 50% reduction of the traffic volume results in a 3 dB reduction in noise levels, regardless of the absolute number of vehicles.

B.9.7 Reducing traffic volumes on one road often implies increasing the volume on other routes. This does not necessarily lead to higher noise levels, because increasing the traffic volume on an already heavily used road might not or only slightly increase the noise level there.




B.9.8 The effects of traffic flows and composition can be modelled using standard calculation methodologies such as CRTN.


B.9.9 Any alterations in traffic flows or any restrictions to vehicle movements could have implications on road safety, journey times, accessibility or the environment (air quality).

B.9.10 For example, a reduction in the traffic volumes on a road could lead to increases in speed because the remaining vehicles can drive more freely, unless measures are taken to keep the speed down.

B.9.11 Any noise mitigation measures involving HGVs should not impose undue burdens or restrictions on commercial activity.



B.10 Traffic Calming and Speed Limits



Applicability Road


Medium Term


Regional/ City


Background

B.10.1 Traffic calming schemes have been introduced by many local authorities with the aim of reducing traffic speeds and in doing so minimising accidents and injuries and improving road safety. A reduction in the overall speed of traffic is one of the ways of reducing noise levels. Traffic speeds can be reduced or limited through a number of physical measures including:

• Static speed limit signs/ live speed indicator signs and policing

• Automatic speed monitoring and fines (speed cameras)

• Road humps and cushions

• Chicanes

• Road narrowing and road bending

• ‘Striping’ of the road to give the motorist a greater awareness of speed

• Combination of measures.

B.10.2 Static speed limits are not always effective on their own and they may need to be used in conjunction with various enforcement methods such as policing and speed cameras to achieve the required speed reductions.

B.10.3 The use of humps or cushions involves the introduction of physical restrictions onto the road to deflect the traffic vertically.

B.10.4 The use of chicanes involves the introduction of physical restrictions onto the road to deflect the traffic horizontally. This could be achieved through a reduction of the width of a street such that two-lane traffic is forced to use a single lane.

B.10.5 Narrowing of the lanes or the road can be established by the introduction of coned or widened areas for pedestrian use or dedicated bicycle lanes. Other methods could involve the introduction of car parking bays perpendicular to the traffic stream, road bending by varying the orientation of parking bays, planting trees to create the impression of a narrow road without necessarily reducing the lane width in reality.

B.10.6 The introduction of rumble strips gives the motorists a greater awareness of their speeds and may lead to a reduction in speeds. However the external noise levels may increase road/ tyre noise as a result of the irregularity in the road surface.

Acoustic Benefits

B.10.7 Although a number of motorists may still exceed the maximum speed limits, the overall traffic speeds are expected to be reduced through the introduction of traffic calming measures.



B.10.8 A reduction in speed from 50 kph to 30 kph could result in noise reductions of up to 3 dB(A)78. This would depend on HGV composition and road surface type. On high speed roads, halving the average vehicle speed could reduce the noise by 5 to 6 dB77. Static speed limit signs tended to have no impact on the actual speed. Variable signs and those informing drivers of their speed were found to be more effective. However, speed reductions cannot always be achieved easily in practice.

B.10.9 The noise reduction effect of humps and cushions depends on the speed reduction achieved. Besides keeping speeds down, humps and cushions may lead to a reduction in traffic levels on a road if the obstacles cause the preference of drivers to shift towards other routes.

B.10.10 The use of road humps and cushions is an option which requires careful consideration. Public perception of road humps may not always be favourable. The proposals can also run into resistance from the emergency services. A TRL study investigated the potential acoustic benefits

of these83:

• Round topped humps could reduce noise by up to 7 dB(A) when the traffic consists of cars only. As the percentage heavy goods vehicle composition increased to about 25%, they gave small noise increases by up to 1 dB(A). It should be ensured that heavy vehicles do not pass the humps at speeds exceeding 25 km/h since at higher speeds noise levels may increase by up to 8 dB.

• Narrow cushions (width less than 1700mm) could reduce noise by about 5 dB(A) when the traffic consists of cars only. As the percentage heavy goods vehicle composition increased to about 25%, they gave small noise increases by up to 2 dB(A).

• Wide cushions and flat-topped humps could increase the noise levels by up to 10 dB(A) when the percentage heavy goods vehicle composition is around 25%. Both of these measures could reduce noise levels by 6 dB(A) to 7 dB(A) when the traffic consists of cars only.

B.10.11 The effect in terms of noise levels depends on the achieved average speed and the change in driving pattern. Depending on traffic volumes and traffic composition, effects have to be calculated for each scenario before implementing chicanes. However, a negative impact on the noise level and/or annoyance is likely.

B.10.12 A review of the literature78 has found little published results on the change in noise levels before and after installing chicanes to reduce vehicle speeds. It is likely that although overall traffic noise levels may be reduced due a lowering of vehicle speeds, maximum noise levels from individual pass-by events may increase due to the change in driving style adopted by some drivers.

B.10.13 Road narrowing77 (coned or widened areas for pedestrian use, dedicated bicycle lanes, perpendicular car parking bays) is capable of substantially reducing the speeds and also the number of noisy events. Noise reductions of typically 2 to 3 dB can be achieved. A potential disadvantage is that too prominent restraints, such as high humps, may cause excessive braking and acceleration, and thus an increase of noise emission.


B.10.14 The reductions in mean traffic speeds along a section of road as a result of traffic calming measures could be modelled using standard calculation methodologies such as CRTN. However the localised effects in peak noise levels may need to be determined through measurements.


B.10.15 The effectiveness of traffic speed restriction methods is highly dependent on design. The measures should introduce sufficient restraint on the motorist to cause speed lowering, without affecting gear changing which could result in a net increase in noise levels.

B.10.16 In general, reducing the speed will also contribute to road safety and improved air quality.

NANR 201- The Costs and Benefits of Remediation Measures

8.10.17 While these measures have been effective, there have been concerns raised by some about disturbance to residents from vehicle noise and ground borne vibration as well as discomfort to road users.




B.11 Smooth Driving



Applicability Road


Medium Term


Regional/ City


Background

B.11.1 The noise emission levels from vehicles are influenced by the vehicle operation including whether the vehicle is accelerating or decelerating. Aggressive driving, especially accelerations, could result in more noise particularly when the initial speed is low. These effects on noise emission levels will be reduced at higher speeds above 50 km/h due to the increased contribution from tyre/road noise.

B.11.2 Variations in vehicle operation are dictated by changes in traffic, road design and conditions, driving styles and driver behaviour and could lead subsequently to variations in noise emissions. Smooth traffic speed profiles could be achieved by:

• Junction design

• Green waves – coordinated signalisation at a number of intersections

• Managed motorways (controlled motorways, dynamic hard shoulder running)

• Roads with less steep gradients (typically less than 10 percent)

• Driver behaviour

• Driving styles.

Acoustic Benefits

B.11.3 The noise levels generated by traffic can be influenced by the vertical alignment of the road. Generally, the steeper the longitudinal gradients, the greater the resulting noise. For a road with a gradient of 10% the resulting noise levels would be 3 dB(A) higher, compared with level roads. According to CRTN, this would apply to upward flows in situations where the carriageways are treated separately or in one-way traffic schemes.

B.11.4 Coordinated signalisation at a number of intersections could allow traffic to flow in a given direction without having to stop at red lights. This would also prevent the need for drivers to speed in order to catch up one signalisation cycle between two intersections. The concept is also known as ‘Green waves’ and would cause smoother driving conditions.

B.11.5 Simulations done as part of the SILENCE project84, comparing a road with signals coordinated in a green wave compared with the same road without coordination indicate that noise levels may go down by 4 dB at intersections. However the noise levels may increase by as much as 3 dB between intersections due to higher speed and increased traffic flow.

B.11.6 By changing the design parameters of a green wave scheme (reducing design speed, cycle time and green time), a reduction of the average speed by 10 to 15 km/h could be achieved85. This corresponds to a noise reduction of 2.5 to 3 dB.



B.11.7 A comprehensive study of the influence of driving styles which involved both car and motorcycle drivers has been carried out in Germany86. Drivers were instructed to either drive aggressively or drive passively. The results showed that on average the noise emission levels from vehicles driven passively were substantially less than compared with the vehicles driven aggressively. For cars the average noise reduction was about 5 dB(A) and for motorcycles was 7 dB(A).

B.11.8 Similarly, it has been suggested that driving style can influence the noise emission levels from commercial vehicles87. Measurements of the noise from commercial vehicles before and after drivers had attended a training course in economical driving indicated reductions in noise level of about 5 dB(A).

B.11.9 Driver behaviour at junctions could also be a factor in affecting noise levels. It has been shown53

that 32 cars driving at 2000 RPM generated no more noise than one car travelling at 4000 RPM. There was a correlation between acceleration and noise for passenger cars. At low speeds of around 30kph, the average noise increase due to acceleration was 2dB. It was noted that the acceleration values that are necessary to follow the traffic flow are much lower than the full acceleration potential of the vehicle.

B.11.10 Various studies have shown that noise levels decrease by 1 to 4dB LAeq where junctions operated by traffic lights have been replaced by more the free flowing roundabouts. The presence of a junction causes the traffic to stop and go and this tends to increase the noise levels. Roundabouts on the other hand allow smoother speed profiles and reduce the frequency of high rates of acceleration. The estimated benefit is 2 dB(A) within 40m of a junction78.

B.11.11 Mini-roundabouts (small paved or painted circles in the centre of intersections) can be used as

traffic calming measures to reduce speed53. The little evidence found on the noise effects of mini- roundabouts indicate that these, when properly designed, may lead to noise reductions due to reductions in speed as well as to more even driving patterns. Based on this, the potential seems to be a noise reduction of up to 4 dB LAeq Results from surveys indicate that roundabouts without overrun areas may reduce noise levels by 1 to 4 dB LAeq compared with ordinary intersections, signalised or non-signalised.


B.11.12 CRTN methodology is designed for predicting noise levels from a free-flowing traffic travelling at speeds greater than 20 kph. It is not able to account for accelerations, decelerations and stop/ start traffic.

B.11.13 The potential acoustic benefits may need to be further established through statistical analysis of carefully conducted ‘before’ and ‘after’ noise measurements on implemented schemes. The benefits could then be incorporated into strategic noise mapping as localised correction terms.


B.11.14 Disadvantage of smoothing traffic profiles is that it can result in an increase in traffic volumes and speeds. This may limit the overall noise benefits.

B.11.15 The measures which affect speed profiles could have implications on road safety, journey times, accessibility or the environment (air quality).



B.12 Noise barriers



Applicability Road

Rail



Classification Measures affecting noise propagation

Background

B.12.1 In situations where there is a concentration of noise-sensitive receivers situated close to a road or a railway line, an effective control method for traffic noise is to erect a barrier or screen alongside the source.

B.12.2 A wide range of materials can be used for constructing barriers. These include earth or recycled fill material, wood, steel, aluminium, concrete, masonry bloc, acrylic sheeting and rubber mats.

B.12.3 There are numerous barrier designs in use88, 89. Some of the main barrier types are summarised below:

• Vertical barriers;

• Barriers with alternative top edge conditions;

• Vegetative barriers comprising a solid core and covered with ivy or willow;

• Earth bunds and landscaping;

• Cuttings & false cuttings;

• Full and partial covers;

• Tunnels.

B.12.4 The main requirement for ensuring acoustic effectiveness is that the barrier should be sufficiently high and long to provide a reasonable vertical and horizontal overlap with the line of sight of the road from the receiver point. The surface mass of the barrier must be high enough to provide a transmission loss of at least 10 dB higher than diffracted sound. The sound leakage through the barrier should be limited to acceptable levels.

B.12.5 Absorbing barriers are widely used to eliminate reverberant build up of sound. However in situations where both sides of the road are surrounded by high-rise buildings, reverberant build up due to the street canyon effect would diminish the performance of barriers.

Acoustic Benefits

B.12.6 A well-conceived noise barrier can reduce the noise level by up to 15 dB(A) under favourable circumstances. When the buildings to be screened are close to routes with HGV traffic, the practically achievable noise reduction is usually of the order of 5 to10 dB. However, at greater distances the screening potential may be substantially lower. In some extreme cases the sound level at a large distance may be higher with the screen than without the screen. This may happen if the noise source is situated low in comparison to the surrounding terrain and the screen is relatively low.



B.12.7 The noise radiated by traffic is influenced by the vertical position of the route. Cuttings would be preferable to routes on embankments or viaducts as far as noise propagation is concerned. In areas where distance cannot be utilized to produce a desired effect the route may be placed low relative to the surrounding terrain (false cutting), or depressed in an actual cutting, where the sides of the cutting act to screen the sensitive area. Routes in cuttings are generally well screened by the edge of the cutting wall. Reflections from the opposite wall, however, can reduce the screening performance unless absorption is used.

B.12.8 The positioning of a barrier with respect to source and receiver is important for maximising its performance. Typically, the longer the additional distance travelled by sound over or around a barrier, the greater the benefits. Cranked top barriers, returns on barrier ends or the use of partial or complete covers are good examples of this.

B.12.9 For some barrier types, data on the acoustic performance are not yet sufficiently available to allow predicting the impact on noise for specific local settings.

B.12.10 Additional acoustic benefits can be achieved by the use of extra diffracting edges or the use of absorbent materials around diffracting edges. However there are few commercial products available.

B.12.11 Noise barriers will only provide benefit to those properties and open spaces located behind the noise barrier. The presence of multiple reflections could degrade the performance of barriers. The use of absorbent materials on vertical faces is one of the ways of avoiding this problem.

B.12.12 Roads or railway lines fully covered or in a tunnel would provide the most acoustically effective means of noise screening. Tunnels could be more cost-effective when built in urban centres where land is very expensive, and especially when they can be covered with buildings.


B.12.13 The CRTN and CRN models can be used to assess the screening by simple reflective and absorptive barriers.

B.12.14 Tunnels could be modelled by effectively assuming that there is no traffic along the relevant section of road or railway (i.e. traffic is fully screened).

B.12.15 For alternative barrier types where a simple ‘path length difference’ approach is not applicable, there may be a need to allow for the barrier screening effects empirically. The acoustic benefits could be simulated by adding a notional height to the existing barrier. Some advice on modelling

alternative barrier types is given in ISO 9613-2:199691.


B.12.16 The acceptability of installation of barriers may often be governed by non-acoustic constraints. Examples are availability of space, safety aspects, access, visual and aesthetic considerations, transmission of light, vandalism and graffiti, engineering constraints, durability, maintenance issues and cost.

B.12.17 The use of photovoltaic barriers in combination with novel barrier applications (e.g. T-profile barriers) could provide added acoustic benefits as well as generation of electricity. However further work is required to optimise the system in terms of both noise reduction and energy conversion.

B.12.18 Tunnels might benefit the local air quality. Construction costs and the costs for maintenance, illumination and ventilation of tunnels are high.



B.13 Vegetation



Applicability Road

Rail




Background

B.13.1 Vegetation could be used more conventionally to prevent the spread of noise from the source or to minimise multiple reflection effects90. They could also have psychological and aesthetic benefits which have a bearing on noise levels or their acceptability.

B.13.2 Some of the direct and indirect effects of vegetation on the noise environment are as follows:

• Barrier screening effect from vegetation;

• Scattering of reflections in narrow city canyons;

• Psychological effects on drivers;

• Psychological effects on residents;

• Effects on soundscapes.

Acoustic Benefits

B.13.3 In order to be acoustically effective, a cover of vegetation would need to comprise a wide belt of high trees combined with dense low level shrubbery. Approximately 0.5 dB LAeq noise reduction could be expected per 10m depth of foliage91.

B.13.4 The use of trees could be useful in absorbing and scattering multiple reflections. Multiple reflections between opposite surfaces may lead to a reverberant build up of sound and to an increase in noise levels. This may arise in street canyons with buildings on both sides of the road, in parallel barrier situations, near cuttings with vertical walls and adjacent to covers and tunnels with reflective surfaces.

B.13.5 Vegetation can also contribute indirectly to noise environment. As discussed in previous sections, planting trees along a road can create the impression of a narrow road without necessarily reducing the lane width in reality. This can reduce the traffic speeds and lead to a reduction in noise. Where the noise source is not visible, this can also affect the perception of noise and reduce annoyance. Due to the pleasing appearance of vegetation and its strong association with nature, people would prefer to hear the sound of rustling leaves or birds singing, even though the actual noise levels could be high.


B.13.6 The effects of vegetation cannot be accounted for using standard methodologies such as CRTN.


B.13.7 Vegetation would become more effective as it got taller and denser, although deciduous plants may have limited effect during the winter months.



B.14 Land Use Planning and Management



Applicability Road

Rail




Background

B.14.1 The basic idea behind land use planning and management is to separate the noise sources and noise-sensitive areas from each other.

B.14.2 This can be achieved by moving the noise-sensitive areas away from noise sources where possible, or leaving a buffer zone between the two. Alternative method is to utilise the buffer zone for development which is not noise-sensitive and to use these buildings as noise barriers. The measures available as part of land use planning are:

• Location of noise sources, spatial separation;

• Noise zoning;

• Using insensitive properties;

• Buildings used as barriers.

Acoustic Benefits

B.14.3 Typically a 3 dB(A) noise reduction can be expected for every doubling of distance between a line source and a receiver. Close to the noise source, benefits of increasing the separation distance can be realised much easier. As the distance between the source and the receiver increases, it becomes progressively more difficult to achieve significant noise reductions.

B.14.4 Noise zoning aims to restrict noise-sensitive development near high noise level areas or to ensure necessary mitigation measures are in place before such development can go ahead. This approach is already in use in the UK92.

B.14.5 The noisy strips of land could be used for the development of commercial or industrial uses since these are generally considered to be less sensitive to noise. The resulting buildings could be used to protect noise-sensitive development further back. Some of the main factors which would determine the acoustic benefits are the height of the buildings used as barriers and the presence of other noise sources.


B.14.6 The acoustic effects of separating the noise-sensitive receiver form the source and using buildings to minimise the spread of noise can be modelled using standard methodologies such as CRTN and CRN.


B.14.7 The cost of land and demand for various types of development could limit the applicability of this strategy in practice.



B.15 Building Design



Applicability Road

Rail



Classification Measures at noise-sensitive receiver

Background

B.15.1 This strategy would include both external and internal measures associated with the design of a building.

B.15.2 External measures could comprise insulation of building fabric (outer walls, windows, and roof), building isolation against vibration and structure-borne sound near railways and tramlines, shape and orientation of the building to minimise the potential noise effects.

B.15.3 Internal measures could involve arranging the room plan so that noise-sensitive spaces are separated from the noise source by the use of non-sensitive spaces.

Acoustic Benefits

B.15.4 A well-designed building could reduce the external noise levels by up to 40 dB(A) inside the living spaces with the windows. The performance of the building fabric as a whole would depend on the performance of façade elements, including glazing and ventilation and could be affected by weaknesses in construction. The internal noise levels which can be achieved would further depend on the type of noise source and the acoustic characteristics of the receiving room. For an open window, the noise reductions could be as low as 10 dB(A). Further details are provided in Appendix F.

B.15.5 The overall reductions would depend on the acoustic performance of individual building elements. The weakest elements are likely to be doors, windows and the roof.


B.15.6 The potential benefits would need to be assessed separately from strategic noise mapping.


B.15.7 There would be a number of planning, engineering and land-use issues associated with the design of buildings which would need to be taken into account.



B.16 Economic and Social Regulating Methods



Applicability Road

Rail


Implementation area National to

International

Classification Economic and social regulating methods

Background

B.16.1 A number of methods are available to policy makers to ensure the mechanisms for achieving noise reductions are in place77:

• Noise emission limits (type approval testing under standard conditions, in-use testing and certification as part of M.O.T. roadside checks on noisy vehicles or illegal exhausts);

• Encourage a switch to other modes of transport (a shift from road to rail);

• Favouring low-noise transport modes (low noise public transport, renewal of public transport, light transport, freight transport);

• Community development (increasing density of community macrostructure, reduction of need for transport);

• Economic instruments (motor vehicle taxes and charges, fuel pricing, road pricing);

• Other economic incentives (compensation, tradable permits, promotion of quieter vehicles through grants and subsidies);

• Education & Information (training to influence driver behaviour, noise labelling, public awareness).

B.16.2 The implementation and effectiveness of some of the technical measures discussed earlier in this report would depend on availability of relevant policies to support these measures.

Acoustic Benefits

B.16.3 The acoustic benefits of alternative transport modes, community wide measures and noise emission limits would depend on how well the policy has been implemented and how it affects the various noise sources in practice. The main idea behind these concepts would be to remove as many private cars from the roads as possible and to ensure the cars in use are as quiet as possible.

B.16.4 Economic and financial methods could be used to support these drives and to raise the funds for compensation for affected people and for noise abatement. There would be a need for community wide campaigns to provide information about noise issues such that the relevant policies are also supported by people.

B.16.5 For example, encouraging residents to use alternative transport modes such as walking, cycling and public transport are good examples of how the use of cars could be reduced. Measures to promote a modal shift in favour of these modes can include more attractive public transport, high quality cycling facilities; integrated car parking policy, park & ride facilities, mobility management and awareness raising campaigns.




B.16.6 The effects of changes to traffic flows and composition as a result of particular strategies or measures to encourage a switch to a different mode of transport can be modelled using standard calculation methodologies, as long as the full impacts on traffic levels are known.


B.16.7 The measures which could be considered as part of economic and social regulation would have impacts on a number of policies.

77 European Commission Working Group (WG5), Inventory of Noise Mitigation Measures, July 2002

78 Traffic Noise Reduction Toolkit, Watts, G.R., Abbott, P.G. and Nelson, P.M., TRL Published Project Report PPR 047, 2005

79 An examination of vehicle noise test procedures, Watts G, Nelson P, Treleven C, Balsom M, TRL Published Project Report PPR 044, 2005

80 Report of promising new road surfaces for testing, Ripke, O., Andersen, B., Bendtsen, H.,

Sandberg, U., SILENCE Deliverable Number F.D4, August 2005

81 SILENCE sub-project G on Rail Infrastructure and Operation, http://www.silence-ip.org, [accessed 10 August 2009]

82 Noise Classification Methods for Urban Road Surfaces, W Bartolomaeus, SILENCE

Deliverable Number F.D14, 2008

83 Traffic calming: vehicle noise emissions alongside speed control cushions and road humps, Abbott, P, Tyler, J. and Layfield, R, TRL Report 180, 1995

84 Methods for noise control for traffic management: impact of speed reducing equipments, Berengier, M. and Picaut, J, SILENCE project, deliverable H.R2, 2008

85 Calming waves for safety. A time to rethink green waves, Ellenberg, M. and Bedaux, J.F, Traffic Technology International, volume 6, number 2, pp 55-58, 1999

86 Leise fahren, Kraftstoff sparen; Grunlargen, energiessparender Fahrweise. Kemper, G. and Steven, H, ADAC Munich, 1984

87 Noise Emissions for road vehicles and provisions for noise reductions, Kemper, G,

Proceedings of Internoise 85, Munich, 1985 88 Noise Barrier Review, Watts, G. R. and Morgan, P.A, TRL Published Project Report PPR

046, 2005 89 A Review of Research on Environmental Noise Barriers, Ekici, I. and Bougdah, H, Building

Acoustics, Volume 10, Number 4, pp 289-323, 2003 90 The use of vegetation for traffic noise screening, Huddart, L, TRRL Research Report 238,

Department of Transport, 1990 91 ISO 9613 Acoustics – Attenuation of Sound During Propagation Outdoors, Part 2; General

Method of Calculation, 1996 92 PPG 24, Planning Policy Guidance: Planning and Noise, Annex 1, Department of the

Environment, 1994



Appendix C - Valuation Methods



C.1 Introduction

C.1.1 This appendix gives an overview of different valuation methods and a summary of the TAG valuation approach provided in its unit 3.3.2.

C.2 Environmental Valuation Methods

C.2.1 A DEFRA study dated 200693 highlighted a number methods for valuing environmental goods and services. Market prices can be used to provide a measure of value for those goods and services traded in markets. However, like noise, for may environmental goods and services (such as the provision of clean air) there are no markets. When this is the case, other approaches are necessary to measure value.

C.2.2 The study categorised valuation methods as either economic or “deliberative and participatory”, with the primary distinction being that the valuation of economic methods was in monetary terms whilst for the deliberative and participatory methods valuation was in non-monetary terms.

C.2.3 The DEFRA study categorised three main approaches to the valuation in monetary terms of goods and services that are not traded in markets:

• Market price proxies (and the production function approach) – these approaches use market prices for traded goods and services as a proxy for the value of non-traded goods and services. For example, the price paid by people to mitigate noise provides a lower bound value of the impact of the noise (as a rationale, informed agent will not spend more on such mitigation than he expects to receive as a benefit). In contrast to economic approaches to valuation (including revealed preference), such market price proxies do not reflect willingness to pay (and concepts of economic value, such as consumers’ surplus).

• Revealed preference methods (hedonic property pricing, travel cost method, random utility models) – these methods rely on valuing non-traded goods and services by using data from complementary markets. For example, in the case of hedonic property pricing, the nuisance value of noise can be measured using market data on property prices, with house prices in noisy locations likely to be cheaper than, otherwise, comparable houses in quiet locations. In contrast to market price proxies, such methods rely on economic concepts of value.

• Stated preference methods (contingent valuation, choice modelling and conjoint analysis) – these methods rely on valuing non-traded goods and services by using data from constructed markets. For example, in contingent valuation, people will be asked what they are willing to pay for a benefit, such as reduced noise at night (or willing to accept for a cost).

C.2.4 Another approach to economic valuation takes evidence from a range of studies (which could include revealed and stated preference approaches) and applies the results in a new context. This approach is referred to as benefits transfer.

C.2.5 The DEFRA study of 2006 identified a number of other valuation methods, which it described as deliberative and participatory. These valuation methods included survey approaches, focus groups, citizens’ juries, health-based approaches, Q Methodology, Delphi surveys and systematic reviews.

C.3 Noise Valuation Methods

C.3.1 The most common methods for investigating the economic costs of noise are listed below (EC Green Paper,19961):

• Change of the market value of properties; hedonic pricing;

• Willingness to pay based on surveys (contingent valuation);

• Cost for abatement measures;



• Cost of avoidance or prevention;

• Cost of medical care and production losses.

C.3.2 Navrud94 (Appendix 2, Review of Studies on External Costs of Noise by Hawkins, 1999) found that hedonic pricing is the most popular valuation method, but studies have also used contingent valuation, abatement costs, avoidance costs and productivity loss to estimate the external costs of noise.

C.3.3 The review pointed out the difficulty of making a comparison between different types of studies without complete information about the population sampled, their properties and the noise levels to which they were exposed to.

C.3.4 The main valuation methods applicable to noise, as well as the strengths and shortcomings of the methods, are described below. The following definitions are mostly from the Defra (2006)93 report.

Hedonic Property Pricing93

C.3.5 Hedonic property pricing is based on the market prices of houses and the characteristics which influence these prices, including environmental quality (such as noise and air pollution, and views). Using statistical techniques, this approach seeks to isolate the contribution to price of each of these characteristics. For example, with information on noise levels, the outputs could be used to estimate the price paid for a lower level of noise. This estimate can, in turn, be used to value noise mitigation measures.

C.3.6 Advantages of the hedonic pricing method are that it uses actual market data (and therefore reflects actual behaviour and willingness to pay for less noise) and that it is well grounded in economic theory. However, it requires both large amounts of data (which are costly to collect) and considerable expertise in data analysis. Moreover, care needs to be taken in transferring results from hedonic property pricing studies from one context to another. Hedonic pricing studies in different countries and different areas of the same country may vary, as they depend on how the model is specified as well as the conditions of the local housing market.

Contingent Valuation Method93

C.3.7 The contingent valuation (CV) method uses surveys to elicit a person’s willingness to pay for a specified environmental change. Typically, surveys will ask respondents directly their willingness to pay for a change (such as a reduction in noise).

C.3.8 An advantage of CV over some other approaches is that it provides a measure of willingness to pay, which is a preferred measure of value. However, unlike hedonic pricing, the measure is not based on actual market data, but rather on people’s stated preferences. Arguably, this provides a less robust basis for measurement, although careful survey design can mitigate this risk. For example, ensuring that the respondent is clear about the subject matter being discussed and asking them to explain the reason behind the answers given. Another advantage of CV methods over hedonic property pricing is that it offers more flexibility; for example, it could be used to estimate willingness to pay for noise reduction in areas such as schools, parklands, etc. Also, compared to the very data intensive requirements of hedonic property pricing, CV methods are less data intensive and arguably easier to implement.

Choice Modelling93

C.3.9 Choice modelling is also a survey method that captures willingness to pay from stated preferences. However, in contrast to CV methods, choice modelling elicits respondents’ willingness to pay indirectly by having them rank or rate alternative options. Through their choices, respondents’ willingness to pay for the alternative options is inferred.

C.3.10 Advantages of choice modelling over CV are that, arguably, it allows for easier analysis of different changes to the options considered (in CV, changes need to be explicitly designed and included in the survey) and that it avoids some of the potential biases of CV (where people can,



arguably, provide strategic responses to achieve a desired outcome, rather than stating their genuine preference). However, choice modelling surveys are complex and must be carefully designed to ensure reliable data is obtained.

Abatement Cost and Avoidance Cost95

C.3.11 The abatement cost approach looks at reducing the noise levels without reducing the activity causing the noise. It is possible, for example, to install barriers or sound insulation which will reduce the noise levels at a receptor. The improved welfare of the receptor due to the reduced noise levels can be valued by looking at the cost of the noise reduction method.

C.3.12 The avoidance cost approach looks to value the voluntarily incurred costs or implied expenditures of people to avoid noise. For example, the cost of soundproofing a house by installing double glazing to reduce road traffic noise levels could be used to value the noise nuisance caused by the road traffic.

C.3.13 The avoidance costs probably only estimate the minimum value placed on the noise nuisance and can not be considered to be a true reflection of the full noise nuisance. There is the possibility that the incurred cost does not solely represent the desire to reduce noise.

Health Based Approaches93

C.3.14 There are several types of health-based approaches: quality, utility and disability-adjusted life years or life expectancy and healthy-year equivalents. These are based on measuring the value of health impacts in terms of the health-based impacts and not the willingness of individuals to pay to avoid them (though they can also be combined with monetary valuation).

C.3.15 A quality-adjusted life year (QALY) combines two key dimensions of health outcomes: the degree of improvement/deterioration in health, and the time interval over which this occurs, including any increase/decrease in the duration of life itself. Disability-adjusted life years (DALY) have similar grounding, but aim not to measure the degree of improvement arising from an intervention, but rather to measure the total amount of healthy life lost, whether from premature mortality or from some degree of disability during a period of time (or indeed both). Healthy-years equivalent (HYE) differs by involving valuation of whole-life sequences of health states which can change over time.

C.3.16 Health costs can be approximated by determining the medical costs incurred due to a certain illness whether paid by the national health system or the patient. Costs associated with loss of productivity due to illness can also be estimated.

C.4 TAG Valuation Guidance

C.4.1 This section provides a summary of the data used in the DfT methodology for valuing changes in noise due to transportation schemes. Three data sets are required, which are presented below, and the overall valuation process is described at the end of this section.

Willingness to Pay Values

C.4.2 The DfT guidance for valuation for changes in noise is given in its TAG unit 3.3.240. This provides, in 2002 prices, the annual value of the willingness to pay for a change in noise in LAeq, 18h, in 1dB changes. Table 2 in the unit provides the valuation, and is repeated below:



Table C.1 - Monetary valuation of changes in noise level (per household, 2002 prices)

LAeq, 18h Low LAeq, 18h High £ per household per dB change

<45 0.0

45 46 8.4

46 47 11.1

47 48 13.7

48 49 16.3

49 50 19.0

50 51 21.6

51 52 24.2

52 53 26.9

53 54 29.5

54 55 32.1

55 56 34.8

56 57 37.4

57 58 40.0

58 59 42.7

59 60 45.3

60 61 48.0

61 62 50.6

62 63 53.2

63 64 55.9

64 65 58.5

65 66 61.1

66 67 63.8

67 68 66.4

68 69 69.0

69 70 71.7

70 71 74.3

71 72 76.9

72 73 79.6

73 74 82.2

74 75 84.9

75 76 87.5

76 77 90.1

77 78 92.8

78 79 95.4

79 80 98.0

80 81 98.0

>81 98.0



C.4.3 The research behind this table could not statistically show a difference between zero and a willingness to pay for changes in noise where levels were below 45dB, and this has been used as the lower level for the valuation. Similarly, there was no evidence for a difference in the valuation for changes in noise above 81dB, and the monetary value placed on decibel changes in noise remains constant above this value.

Growth Rates

C.4.4 To account for the growth in the value of the change in noise over time, growth rates need to be applied, and these are given in Table 6 of the TAG noise supplementary guidance, which is repeated below:

Table C.2 - Growth in the Values of Noise Change

Range of years

Real GDP growth,

% per annum

Household growth,

% per annum

Value growth 'adjustment

factor'

Growth in values of noise change, % per annum

2002-2003 2.25 0.75 1.0000 1.48882003-2004 2.50 0.75 1.0000 1.73702004-2005 3.50 0.75 1.0000 2.72952005-2006 3.25 0.75 1.0000 2.48142006-2007 2.75 0.76 1.0000 1.9750 2007-2011 2.50 0.76 1.0000 1.72692011-2021 2.25 0.67 1.0000 1.56952021-2031 1.75 0.33 1.0000 1.41532031-2032 2.00 0.17 1.0000 1.82692032-2036 2.00 0.17 0.8571 1.54172036-2051 2.00 0.00 0.8571 1.71432051-2061 1.75 0.00 0.8571 1.50002061 onwards 2.00 0.00 0.8571 1.7143

Discounting

C.4.5 Benefits which occur in the future must be discounted, and this discounting should be undertaken using the discounting rates provided in the Green Book73, these values are repeated in TAG unit 3.5.439, and are given below:

Table C.3 – Green Book Discounting Rates

Years from the current year

Discount rate

0-30 3.5%

31-75 3.0%

76-125 2.5%

126-200 2.0%

201-300 1.5%

301+ 1.0%

Determining the Net Present Value

C.4.6 The steps to calculate the Net Present Value are given in the supplementary guidance for the TAG unit60.

C.4.7 In summary the initial steps are to:



• Work out the willingness to pay for the change in noise from the above table in the opening year.

• Repeat this for any other future assessment years being considered.

• Use linear interpolation to value changes in noise between the assessment years being considered.

• For years between the last assessment year and the end of the appraisal period, no changes in noise are assumed – i.e. the noise levels remain constant from the last assessment year.

C.4.8 These steps are used to work out the value of the change in noise over every year in the appraisal period.

C.4.9 To determine the overall net present value, changes in the value over time need to be taken into account, and future benefits need to be discounted. The following subsequent steps are required:

• The growth in value from 2002 needs to be taken into account for each year in the appraisal period. The growth values are provided in Table 6 of the supplementary noise guidance, which is repeated above.

• Future values need to be discounted using the standard TAG discount rules. These are given in TAG unit 3.5.4, and are repeated above.

• Sum the discounted values over the appraisal period to determine the net present value.

C.4.10 The noise supplementary guidance notes indicate that the discounting effect is stronger than the growth effect, and this effect means that future benefits become smaller the longer into the future we look.

93 Valuing our natural environment, Final report by eftec in association with Environmental Futures Limited for Defra March 2006

94 The State of the Art on Economic Valuation of Noise, Final report to European Commission DG Environment by Stale Navrud, April 2002

95 The True Cost of Road Transport, Maddison, D et al, Centre for Social and Economic Research on the Global Environment, Blueprint 5, Earthscan Publications Limited, 1996



Appendix D - Methods of Appraisal



D.1 Introduction

D.1.1 This appendix provides an overview for methods of economic appraisal

D.2 Cost-Benefit Analysis (CBA)

D.2.1 The Green Book describes CBA as follows:

• ‘Analysis which quantifies in monetary terms as many of the costs and benefits of a proposal as feasible, including items for which the market does not provide a satisfactory measure of economic value.’

D.2.2 In brief, some of the advantages of CBA as an approach to option appraisal are as follows:

• CBA, appropriately implemented, establishes whether an individual option is worth implementing (i.e. does the option deliver benefits that are greater than the costs) and which of the range of options considered is the best (i.e. the one with the largest net benefit).

• Quantifying all costs and benefits in monetary terms provides at least two advantages:

- First, it provides a single measurement scale for comparing potentially disparate consequences (including not just financial, but social and environmental impacts); and

- Second, it provides a measurement scale which is familiar.

• The process of conducting a CBA has the potential to add as much value as the outputs of the CBA. This statement is based on an NAO conclusion from a review of the conduct of Regulatory Impact Assessments in central government. They found the process had particularly beneficial effects when it: was started early; included effective consultation; and analysed costs and benefits appropriately.96

D.2.3 The main disadvantages of CBA relate to the availability and quality of the data required for a comprehensive CBA. In particular, it might be extremely difficult to monetise certain impacts; for example those impacts that are socially diffuse, such as changes in social cohesion. Moreover, whilst there are various techniques available for monetising non-market impacts, relevant data may either not be readily available or be expensive to collect. It is for this reason that the Green Book emphasises that whilst assessments should be comprehensive, they should also be proportionate. Accordingly, the outcome might be a “constrained CBA”, in which not all costs and benefits are monetised, but all costs and benefits are identified and considered (perhaps using one or more of the below approaches).

D.3 Cost-Effectiveness Analysis (CEA)

D.3.1 The Green Book defines Cost Effectiveness Analysis (CEA) as follows:

• ‘Analysis that compares the costs of alternative ways of producing the same or similar outputs.’

D.3.2 A typical outcome of a CEA is a cost per unit of output, where the output might be, say, a quantity of emissions. CEA enables the ranking of options according to the cost effectiveness by which they provide units of the output of interest.

D.3.3 The main advantage of CEA is that it does not involve monetising benefits and, therefore, may be quicker and easier to conduct than CBA. It is also suggested that CEA is more appropriate than CBA when outputs are prescribed (i.e. by regulation) with no leeway in the required outcome. In such a case, monetising the benefits of each option is unlikely to be worthwhile, as the outcome ought to be the same. In these circumstances, examining only the costs may be a more effective approach than CBA. In practice, where this is done, the analysis is more accurately described as Cost Minimisation Analysis (CMA).



D.3.4 The main disadvantage of CEA is that consideration of the benefits tends to be restricted to different quantities (or qualities) of the same single outcome. Also, CEA does not establish whether an option delivers a net benefit, rather it only identifies the most cost effective option.

D.4 Multi-Criteria Analysis (MCA)

D.4.1 A study prepared for Defra describes Multi-Criteria Analysis (MCA) as follows:93

• ‘Analysis which seeks to rank different options in terms of their weighted performance against a variety of criteria. It allows the examination of various environmental, social and economic impacts separately at first, so it can be used where values are not directly comparable. However when a final non-monetary weighting scheme is applied, either the impacts are aligned via the weights, or a lexicographic ordering places all the emphasis on one set of criteria.’

D.4.2 MCA covers a relatively broad range of techniques which are becoming increasingly used in central government. Guidance on the conduct of MCA in central government was recently republished by the Department for Communities and Local Government.97 MCA techniques typically involve identifying criteria against which to assess options, scoring each of the options against these criteria and then applying weights to these scores to obtain a single, quantitative assessment.

D.4.3 The key advantage of MCA is that, like CBA, it potentially provides for a comprehensive assessment and comparison of costs and benefits. Indeed, it can incorporate other forms of analysis, including monetary values from CEA or constrained CBA. In contrast to CBA, however, it can compare all costs and benefits of options even where these are not monetised.

D.4.4 A disadvantage of MCA is that it tends to require more judgement to be exercised than CBA, e.g. in defining appropriate criteria, establishing scoring systems and developing equitable weights. Accordingly, MCA should not be interpreted as an easy option; the Department for Communities and Local Government’s MCA manual notes “the use of these techniques is in important ways more demanding of experience and good training than the use of CEA … or of CBA”.

D.5 Quantitative Measurement (QM)

D.5.1 In addition to the above, a study for developing ‘Harmonised European Approaches for Transport Costing and Project Assessment’ (HEATCO) 98 identifies further types of analysis used in Europe. This includes Quantitative Measurements (QM), defined as follows:

• ‘The effects are estimated in physical units or numbers (cardinal scale), but in contrast to the multi-criteria analysis (MCA) no specific weights are assigned to allow an aggregation of the effects to a single criterion.’

D.5.2 QM can be a useful complement to a constrained CBA. For example, where some impacts are not monetised, it can be informative to quantify these impacts in other ways, e.g. units of output, number of people affected, etc.

D.6 Qualitative Assessment (QA)

D.6.1 The HEATCO Study also identified Qualitative Assessments, describing it as follows:

• ‘The effects are classified into one of several ranked categories (ordinal scale) based on well- defined standard criteria for each of the categories, which are invariant from project to project.’

D.6.2 In general, in conducting an assessment, it is preferable to quantify the impacts of options (in either monetary or non-monetary terms). However, if this is not practicable then including a QA of un-quantified impacts is important to ensure completeness and transparency of the assessment.



96 Better Regulation – Impact Assessments and External Review, John Aschcroft, Centre for

the Study of Regulated Industries Regulatory Review 2002/3, 2003 97 Multi-criteria analysis: a manual. Department for Communities and Local Government,

January 2009 98 Developing Harmonised European Approaches for Transport Costing (HEATCO) and

Project Assessment, Deliverable 1, Current practice in project appraisal in Europe, T. Odgaard, C. Kelly, J. Laird et al, 2005



Appendix E - Case Study

Results



E.1 Case Study 1

Change in noise level LA10,18h

dB Number of dwellings subject to a change in noise level

Significance

Increase in noise Decrease in noise

= 0 37 37 Neutral

0.1 - 0.9 48 88 Neutral

1 - 2.9 0 54 Slight

3 - 4.9 0 23 Moderate

>=5 0 2 Large

Total >1 0 79 0

Total >3 0 25 0

Table E.1 - Results for replacing the 2m wall with a 4m noise barrier to the north of the road

E.1.1 This shows that there are 54 properties which would receive a slight decrease in noise, 23 would receive a moderate decrease in noise and 2 would receive a large decrease in noise.



Significance


= 0 23 23 Neutral

0.1 - 0.9 2 113 Neutral

1 - 2.9 0 77 Slight

3 - 4.9 0 27 Moderate

>=5 0 10 Large

Total >1 0 114

Total >3 0 37

Table E.2 - Results for replacing the 2m wall with a 4m noise barrier to the north and south of the road

E.1.2 This shows that there are 77 properties which would receive a slight decrease in noise, 27 would receive a moderate decrease in noise and 10 would receive a large decrease in noise. Using an absorbent barrier in place of reflective gives the same results as above because the walls of the existing retained cut are reflective.





Significance


= 0 18 18 Neutral

0.1 - 0.9 0 34 Neutral

1 - 2.9 0 200 Slight

3 - 4.9 0 0 Moderate

>=5 0 0 Large

Total >1 0 200

Total >3 0 0

Table E.3 - Results for resurfacing with a quieter road surface

E.1.3 This shows that there are 200 properties which would receive a slight decrease in noise.



Significance


= 0 16 16 Neutral

0.1 - 0.9 0 36 Neutral

1 - 2.9 0 103 Slight

3 - 4.9 0 72 Moderate

>=5 0 25 Large

Total >1 0 200

Total >3 0 97

Table E.4 - Results for resurfacing and replacing the 2m wall with a 4m noise barrier to the north of the road


E.1.5 These results have been monetised and the costs for the different measures estimated, and these results are shown in the following table:

Noise control measure Monetary value of acoustic

benefit

Economic cost of

measure

Net improvement

4m barrier to the north £93k £318k -£225k

4m barrier both sides £150k £722k -£572k

Resurfacing £194k £123k +£71k

Resurfacing + 4m barrier to the north £282k £441k -£159k

Table E.5 - Monetised results and estimated costs for different measures



E.2 Case Study 2



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 3 Slight

3 - 4.9 0 10 Moderate

>=5 0 1 Large

Total >1 0 14

Total >3 0 11

Table E.6 - Results for introducing a 150m long 2m high noise barrier



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 1 Slight


>=5 0 8 Large

Total >1 0 14

Total >3 0 13




Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight


>=5 0 5 Large

Total >1 0 14

Total >3 0 14






Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight


>=5 0 13 Large

Total >1 0 14

Total >3 0 14




Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight


>=5 0 10 Large

Total >1 0 14

Total >3 0 14




Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight


>=5 0 14 Large

Total >1 0 14

Total >3 0 14





Noise control measure Monetary value

of acoustic benefit

Economic cost of

measure

Net improvement

150m long, 2m high barrier £100k £68k +£32k





250m long, 4m high barrier £220k £233k -£13k

Table E.12 – Monetised results and estimated costs for different measures.

E.3 Case Study 3

E.3.1 Calculations were undertaken to assess the impact of the addition of a barrier to the north of the road, and also for the addition of barriers to both the north and south of the road. For each scenario calculations were under taken based on barrier heights between 1.5m – 4m, in 0.5m increments. The tables below present the results for north barrier, and north and south barrier combinations, for heights of 2m, 3m and 4m. The monetisation and implementation cost for all barrier heights is presented in a separate table at the bottom of this chapter.



Significance


= 0 175 175 Neutral

0.1 - 0.9 0 722 Neutral

1 - 2.9 0 465 Slight

3 - 4.9 0 276 Moderate

>=5 0 161 Large

Total >1 0 902

Total >3 0 437

Table E.13 - Results for introducing a 2m noise barrier to the north of the road






Significance


= 0 147 147 Neutral

0.1 - 0.9 0 597 Neutral

1 - 2.9 0 505 Slight

3 - 4.9 0 283 Moderate

>=5 0 267 Large

Total >1 0 1055

Total >3 0 550





Significance


= 0 125 125 Neutral

0.1 - 0.9 0 524 Neutral

1 - 2.9 0 473 Slight

3 - 4.9 0 271 Moderate

>=5 0 406 Large

Total >1 0 1150

Total >3 0 677





Significance


= 0 157 157 Neutral

0.1 - 0.9 170 749 Neutral

1 - 2.9 0 407 Slight

3 - 4.9 0 192 Moderate

>=5 0 124 Large

Total >1 0 723

Total >3 0 316

Table E.16 - Results for introducing 2m noise barriers to the north and south of the road






Significance


= 0 137 137 Neutral

0.1 - 0.9 69 665 Neutral

1 - 2.9 0 433 Slight

3 - 4.9 0 289 Moderate

>=5 0 206 Large

Total >1 0 928

Total >3 0 495





Significance


= 0 124 124 Neutral

0.1 - 0.9 40 568 Neutral

1 - 2.9 0 477 Slight

3 - 4.9 0 276 Moderate

>=5 0 314 Large

Total >1 0 1067

Total >3 0 590







of acoustic benefit

Economic cost of

measure

Net improvement

1.5m barrier to the north £651k £257k +£394k

2m barrier to the north £801k £322k +£479k

2.5m barrier to the north £945k £386k +£559k

3m barrier to the north £1,080k £450k +£630k

3.5m barrier to the north £1,185k £558k +£627k

4m barrier to the north £1,272k £665k +£607k

1.5m barriers to the north and south £583k £515k +£68k

2m barriers to the north and south £668k £644k +£24k

2.5m barriers to the north and south £788k £772k +£16k

3m barriers to the north and south £914k £901k +£13k

3.5m barriers to the north and south £1,030k £1115k -£85k

4m barriers to the north and south £1,128k £1330k -£202k


E.4 Case Study 4



Significance


= 0 5 5 Neutral

0.1 - 0.9 39 16 Neutral

1 - 2.9 0 0 Slight


>=5 0 0 Large

Total >1 0 0

Total >3 0 0

Table E.20 - Results for introducing a 1.5m noise barrier in the central reserve





Significance


= 0 4 4 Neutral

0.1 - 0.9 29 25 Neutral

1 - 2.9 0 2 Slight


>=5 0 0 Large

Total >1 0 2

Total >3 0 0

Table E.21 - Results for introducing a 2m noise barrier in the central reserve



Significance


= 0 3 3 Neutral

0.1 - 0.9 17 28 Neutral

1 - 2.9 0 12 Slight


>=5 0 0 Large

Total >1 0 12

Total >3 0 0




Significance


= 0 5 5 Neutral

0.1 - 0.9 7 25 Neutral

1 - 2.9 0 23 Slight


>=5 0 0 Large

Total >1 0 23

Total >3 0 0






Significance


= 0 6 6 Neutral

0.1 - 0.9 8 24 Neutral

1 - 2.9 0 22 Slight


>=5 0 0 Large

Total >1 0 22

Total >3 0 0




Significance


= 0 4 4 Neutral

0.1 - 0.9 8 26 Neutral

1 - 2.9 0 22 Slight


>=5 0 0 Large

Total >1 0 22

Total >3 0 0




benefit

Economic cost of

measure

Net improvement

1.5m barrier -£89k £29k -£118k

2m barrier -£41k £36k -£77k

2.5m barrier -£26k £43k -£69k

3m barrier -£11k £50k -£61k

3.5m barrier £33k £62k -£29k

4m barrier £63k £74k -£11k




E.5 Case Study 5



Significance


= 0 30 30 Neutral

0.1 - 0.9 0 41 Neutral

1 - 2.9 0 63 Slight


>=5 0 0 Large

Total >1 0 63

Total >3 0 0

Table E.27 - Results for introducing a 1.5m noise barrier to the north-east of the road




Significance


= 0 30 30 Neutral

0.1 - 0.9 0 29 Neutral

1 - 2.9 0 73 Slight


>=5 0 0 Large

Total >1 0 75

Total >3 0 2

Table E.28 - Results for introducing a 2m noise barrier to the north-east of the road

E.5.2 This shows that there are 73 properties which would receive a slight decrease in noise, and 2 would receive a moderate decrease in noise.





Significance


= 0 29 29 Neutral

0.1 - 0.9 0 29 Neutral

1 - 2.9 0 49 Slight

3 - 4.9 0 27 Moderate

>=5 0 0 Large

Total >1 0 76

Total >3 0 27





Significance


= 0 24 24 Neutral

0.1 - 0.9 0 33 Neutral

1 - 2.9 0 39 Slight

3 - 4.9 0 38 Moderate

>=5 0 0 Large

Total >1 0 77

Total >3 0 38


This shows that there are 39 properties which would receive a slight decrease in noise, and 38 would receive a moderate decrease in noise.



Significance


= 0 24 24 Neutral

0.1 - 0.9 0 31 Neutral

1 - 2.9 0 38 Slight

3 - 4.9 0 41 Moderate

>=5 0 0 Large

Total >1 0 79

Total >3 0 41




This shows that there are 38 properties which would receive a slight decrease in noise, and 41 would receive a moderate decrease in noise.



Significance


= 0 10 10 Neutral

0.1 - 0.9 0 45 Neutral

1 - 2.9 0 34 Slight

3 - 4.9 0 42 Moderate

>=5 0 3 Large

Total >1 0 79

Total >3 0 45





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 45 Slight


>=5 0 0 Large

Total >1 0 45

Total >3 0 0

Table E.33 - Results for resurfacing 200m of carriageway with a quieter road surface






Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 45 Slight


>=5 0 0 Large

Total >1 0 45

Total >3 0 0

Table E.34 - Results for resurfacing 500m of carriageway with a quieter road surface




benefit

Economic cost of

measure

Net improvement

1.5m barrier to the north-east £43k £141k -£98k

2m barrier to the north-east £46k £176k -£130k





200m Resurfacing £38k £42k -£4k


Table E.35 – Monetised results and estimated costs for different measures



E.6 Case Study 6a



Significance


= 0 117 117 Neutral

0.1 - 0.9 3 132 Neutral

1 - 2.9 1 30 Slight


>=5 0 0 Large

Total >1 1 30

Total >3 0 0

Table E.36 - Results for introducing a 1.5m noise barrier to the south of the road

E.6.1 This shows that there is 1 property which would receive a slight increase in noise. There are 30 properties which would receive a slight decrease in noise.



Significance


= 0 87 87 Neutral

0.1 - 0.9 1 142 Neutral

1 - 2.9 3 50 Slight


>=5 0 0 Large

Total >1 3 50

Total >3 0 0

Table E.37 - Results for introducing a 2m noise barrier to the south of the road

E.6.2 This shows that there are 3 properties which would receive a slight increase in noise. There are 50 properties which would receive a slight decrease in noise.





Significance


= 0 73 73 Neutral

0.1 - 0.9 1 139 Neutral

1 - 2.9 3 67 Slight


>=5 0 0 Large

Total >1 3 67

Total >3 0 0


This shows that there are 3 properties which would receive a slight increase in noise. There are 67 properties which would receive a slight decrease in noise.



Significance


= 0 59 59 Neutral

0.1 - 0.9 0 141 Neutral

1 - 2.9 3 55 Slight

3 - 4.9 0 25 Moderate

>=5 0 0 Large

Total >1 3 80

Total >3 0 25


This shows that there are 3 properties which would receive a slight increase in noise. There are 55 properties which would receive a slight decrease in noise, and 25 which would receive a moderate increase in noise.





Significance


= 0 42 42 Neutral

0.1 - 0.9 0 139 Neutral

1 - 2.9 3 62 Slight

3 - 4.9 0 36 Moderate

>=5 0 1 Large

Total >1 3 99

Total >3 0 37


This shows that there are 3 properties which would receive a slight increase in noise. There are 62 properties which would receive a slight decrease in noise, 36 which would receive a moderate increase in noise, and 1 which would receive a large decrease in noise.



Significance


= 0 26 26 Neutral

0.1 - 0.9 0 142 Neutral

1 - 2.9 3 67 Slight

3 - 4.9 0 37 Moderate

>=5 0 8 Large

Total >1 3 112

Total >3 0 45


E.6.3 This shows that there are 3 properties which would receive a slight increase in noise. There are 67 properties which would receive a slight decrease in noise, 37 which would receive a moderate increase in noise, and 8 which would receive a large decrease in noise.





of acoustic benefit

Economic cost of

measure

Net improvement

1.5m barrier to the south £151k £232k -£81k

2m barrier to the south £244k £290k -£46k

2.5m barrier to the south £332k £348k -£16k

3m barrier to the south £467k £406k +£61k

3.5m barrier to the south £554k £503k +£51k

4m barrier to the south £590k £600k -£10k


E.7 Case Study 6b



Significance


= 0 1 1 Neutral

0.1 - 0.9 0 13 Neutral

1 - 2.9 0 63 Slight


>=5 0 0 Large

Total >1 0 66

Total >3 0 3

Table E.43 - Results for introducing a 1.5m noise barrier to the north of the road

There are 63 properties which would receive a slight decrease in noise, and 3 which would receive a moderate decrease in noise.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 5 Neutral

1 - 2.9 0 61 Slight

3 - 4.9 0 13 Moderate

>=5 0 1 Large

Total >1 0 75

Total >3 0 14


E.7.1 There are 61 properties which would receive a slight decrease in noise,13 which would receive a moderate decrease in noise, and 1 which would receive a large decrease in noise.





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 2 Neutral

1 - 2.9 0 35 Slight

3 - 4.9 0 33 Moderate

>=5 0 10 Large

Total >1 0 78

Total >3 0 43


E.7.2 There are 35 properties which would receive a slight decrease in noise,33 which would receive a moderate decrease in noise, and 10 which would receive a large decrease in noise.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 1 Neutral

1 - 2.9 0 15 Slight

3 - 4.9 0 46 Moderate

>=5 0 18 Large

Total >1 0 79

Total >3 0 64


E.7.3 There are 15 properties which would receive a slight decrease in noise, 46 which would receive a moderate decrease in noise, and 18 which would receive a large decrease in noise.





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 1 Neutral

1 - 2.9 0 8 Slight

3 - 4.9 0 42 Moderate

>=5 0 29 Large

Total >1 0 79

Total >3 0 71





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 1 Neutral

1 - 2.9 0 5 Slight

3 - 4.9 0 31 Moderate

>=5 0 43 Large

Total >1 0 79

Total >3 0 74





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 80 Slight


>=5 0 0 Large

Total >1 0 80

Total >3 0 0

Table E.49 - Results for introducing 555m of quieter road surfacing



E.7.6 There are 80 properties which would receive a slight decrease in noise.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 12 Slight

3 - 4.9 0 59 Moderate

>=5 0 9 Large

Total >1 0 80

Total >3 0 68

Table E.50 - Results for introducing 555m of quieter road surfacing combined with introducing a 1.5m noise barrier to the north of the road

There are 12 properties which would receive a slight decrease in noise, 59 which would receive a moderate decrease in noise, and 9 which would receive a large decrease in noise.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 11 Slight

3 - 4.9 0 50 Moderate

>=5 0 19 Large

Total >1 0 80

Total >3 0 69

Table E.51 - Results for introducing 555m of quieter road surfacing combined with introducing a 2m noise barrier to the north of the road

There are 11 properties which would receive a slight decrease in noise, 50 which would receive a moderate decrease in noise, and 19 which would receive a large decrease in noise.





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 5 Slight

3 - 4.9 0 27 Moderate

>=5 0 48 Large

Total >1 0 80

Total >3 0 75





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 2 Slight

3 - 4.9 0 18 Moderate

>=5 0 60 Large

Total >1 0 80

Total >3 0 78







Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 2 Slight

3 - 4.9 0 15 Moderate

>=5 0 63 Large

Total >1 0 80

Total >3 0 78





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 2 Slight

3 - 4.9 0 12 Moderate

>=5 0 66 Large

Total >1 0 80

Total >3 0 78







of acoustic benefit

Economic cost of

measure

Net improvement

1.5m barrier to the north £50k £177k -£127k







555m Resurfacing with 1.5m barrier to the north

£120k £307k

-£187k

555m Resurfacing with 2m barrier to the north

£144k £351k

-£207k


£155k £396k

-£241k


£185k £440k

-£255k


£198k £513k

-£315k


£224k £587k

-£363k


E.8 Case Study 7



Significance


= 0 136 136 Neutral

0.1 - 0.9 0 59 Neutral

1 - 2.9 0 28 Slight

3 - 4.9 0 22 Moderate

>=5 0 12 Large

Total >1 0 62

Total >3 0 34

Table E.57 - Results for introducing a 2m noise barrier to the south-east of the road






Significance


= 0 93 93 Neutral

0.1 - 0.9 0 100 Neutral

1 - 2.9 0 20 Slight

3 - 4.9 0 18 Moderate

>=5 0 26 Large

Total >1 0 64

Total >3 0 44





Significance


= 0 58 58 Neutral

0.1 - 0.9 0 135 Neutral

1 - 2.9 0 18 Slight

3 - 4.9 0 16 Moderate

>=5 0 30 Large

Total >1 0 64

Total >3 0 46





benefit

Economic cost of

measure

Net improvement

2m barrier to the south-east £292k £71k +£221k



Table E.60 – Monetised results and estimated costs of different measures



E.9 Case Study 8



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 3 2 Slight


>=5 0 0 Large

Total >1 3 4

Total >3 0 2

Table E.61 - Results for introducing a 1.5m reflective noise barrier



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 3 0 Slight


>=5 0 2 Large

Total >1 3 4

Total >3 0 4

Table E.62 - Results for introducing a 3m reflective noise barrier



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 3 0 Slight


>=5 0 2 Large

Total >1 3 4

Total >3 0 4

Table E.63 - Results for introducing a 4m reflective noise barrier





Significance


= 0 3 3 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 2 Slight


>=5 0 0 Large

Total >1 0 4

Total >3 0 2

Table E.64 - Results for introducing a 1.5m absorbent barrier



Significance


= 0 3 3 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight


>=5 0 2 Large

Total >1 0 4

Total >3 0 4

Table E.65 - Results for introducing a 3m absorbent barrier



Significance


= 0 2 2 Neutral

0.1 - 0.9 0 1 Neutral

1 - 2.9 0 0 Slight


>=5 0 2 Large

Total >1 0 4

Total >3 0 4

Table E.66 - Results for introducing a 4m absorbent barrier





of acoustic benefit

Economic cost of

measure

Net improvement

1.5m reflective barrier -£10k £97k -£107k

3m reflective barrier £16k £170k -£154k

4m reflective barrier £16k £251k -£235k

1.5m absorbent barrier £10k £162k -£152k

3m absorbent barrier £35k £284k -£249k

4m absorbent barrier £35k £446k -£411k


E.10 Case Study 9



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 20 Neutral

1 - 2.9 0 21 Slight

3 - 4.9 0 12 Moderate

>=5 0 0 Large

Total >1 0 33

Total >3 0 12

Table E.68 - Results for introducing 580m of 1.5m noise barrier to the north of the road

E.10.1 There are 21 properties which would receive a slight decrease in noise, and 12 which would receive a moderate decrease in noise.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 16 Neutral

1 - 2.9 0 18 Slight

3 - 4.9 0 15 Moderate

>=5 0 4 Large

Total >1 0 37

Total >3 0 19

Table E.69 - Results for introducing 580m of 2m noise barrier to the north of the road



E.10.2 There are 18 properties which would receive a slight decrease in noise, 15 which would receive a moderate decrease in noise, and 4 would receive a large decrease in noise.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 16 Neutral

1 - 2.9 0 15 Slight

3 - 4.9 0 13 Moderate

>=5 0 9 Large

Total >1 0 37

Total >3 0 22





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 14 Neutral

1 - 2.9 0 14 Slight

3 - 4.9 0 13 Moderate

>=5 0 12 Large

Total >1 0 39

Total >3 0 25







Significance


= 0 0 0 Neutral

0.1 - 0.9 0 14 Neutral

1 - 2.9 0 14 Slight


>=5 0 17 Large

Total >1 0 39

Total >3 0 25





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 14 Neutral

1 - 2.9 0 14 Slight


>=5 0 17 Large

Total >1 0 39

Total >3 0 25





Significance


= 0 10 10 Neutral

0.1 - 0.9 0 26 Neutral

1 - 2.9 0 16 Slight


>=5 0 0 Large

Total >1 0 17

Total >3 0 1







Significance


= 0 8 8 Neutral

0.1 - 0.9 0 24 Neutral

1 - 2.9 0 18 Slight


>=5 0 0 Large

Total >1 0 21

Total >3 0 3





Significance


= 0 6 6 Neutral

0.1 - 0.9 0 21 Neutral

1 - 2.9 0 20 Slight


>=5 0 0 Large

Total >1 0 26

Total >3 0 6







Significance


= 0 6 6 Neutral

0.1 - 0.9 0 18 Neutral

1 - 2.9 0 19 Slight

3 - 4.9 0 10 Moderate

>=5 0 0 Large

Total >1 0 29

Total >3 0 10





Significance


= 0 5 5 Neutral

0.1 - 0.9 0 18 Neutral

1 - 2.9 0 19 Slight

3 - 4.9 0 10 Moderate

>=5 0 1 Large

Total >1 0 30

Total >3 0 11





Significance


= 0 5 5 Neutral

0.1 - 0.9 0 18 Neutral

1 - 2.9 0 19 Slight


>=5 0 2 Large

Total >1 0 30

Total >3 0 11







benefit

Economic cost of

measure

Net improvement

580m of 1.5m barrier to the north £145k £209k -£64k

580m of 2m barrier to the north £174k £261k -£87k












E.11 Case Study 10



Significance


= 0 2 2 Neutral

0.1 - 0.9 4 1 Neutral

1 - 2.9 0 1 Slight


>=5 0 0 Large

Total >1 0 3

Total >3 0 2

Table E.81 - Results for introducing a 2m noise barrier





Significance


= 0 2 2 Neutral

0.1 - 0.9 4 1 Neutral

1 - 2.9 0 0 Slight


>=5 0 2 Large

Total >1 0 3

Total >3 0 3

Table E.82 - Results for introducing a 4m noise barrier

E.11.1 These results have been monetised and the costs for the different measures estimated, and these

results are shown in the following table:


benefit

Economic cost of

measure

Net improvement




E.12 Case Study 11



Significance


= 0 22 22 Neutral

0.1 - 0.9 0 70 Neutral

1 - 2.9 0 11 Slight


>=5 0 0 Large

Total >1 0 11

Total >3 0 0

Table E.84 - Results for introducing a 1.5m noise barrier to the east of the road






Significance


= 0 9 9 Neutral

0.1 - 0.9 0 57 Neutral

1 - 2.9 0 32 Slight


>=5 0 0 Large

Total >1 0 37

Total >3 0 5

Table E.85 - Results for introducing a 2m noise barrier to the east of the road




Significance


= 0 3 3 Neutral

0.1 - 0.9 0 49 Neutral

1 - 2.9 0 39 Slight


>=5 0 3 Large

Total >1 0 51

Total >3 0 12


E.12.3 This shows that there are 39 properties which would receive a slight decrease in noise, 9 would receive a moderate decrease in noise, and 3 would receive a large decrease in noise.





Significance


= 0 1 1 Neutral

0.1 - 0.9 0 40 Neutral

1 - 2.9 0 48 Slight

3 - 4.9 0 11 Moderate

>=5 0 3 Large

Total >1 0 62

Total >3 0 14





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 38 Neutral

1 - 2.9 0 47 Slight

3 - 4.9 0 12 Moderate

>=5 0 6 Large

Total >1 0 65

Total >3 0 18







Significance


= 0 0 0 Neutral

0.1 - 0.9 0 30 Neutral

1 - 2.9 0 52 Slight

3 - 4.9 0 13 Moderate

>=5 0 8 Large

Total >1 0 73

Total >3 0 21





Significance


= 0 37 37 Neutral

0.1 - 0.9 0 27 Neutral

1 - 2.9 0 9 Slight


>=5 0 0 Large

Total >1 0 9

Total >3 0 0

Table E.90 - Results for introducing a 1.5m noise barrier to the west of the road




Significance


= 0 35 35 Neutral

0.1 - 0.9 0 25 Neutral

1 - 2.9 0 6 Slight


>=5 0 0 Large

Total >1 0 13

Total >3 0 7

Table E.91 - Results for introducing a 2m noise barrier to the west of the road



E.12.8 This shows that there are 6 properties which would receive a slight decrease in noise, and 7 which would receive a moderate decrease in noise.



Significance


= 0 32 32 Neutral

0.1 - 0.9 0 27 Neutral

1 - 2.9 0 6 Slight


>=5 0 2 Large

Total >1 0 14

Total >3 0 8


E.12.9 This shows that there are 6 properties which would receive a slight decrease in noise, 6 which would receive a moderate decrease in noise, and 2 which would receive a large decrease in noise.



Significance


= 0 28 28 Neutral

0.1 - 0.9 0 30 Neutral

1 - 2.9 0 7 Slight


>=5 0 8 Large

Total >1 0 15

Total >3 0 8


E.12.10 This shows that there are 7 properties which would receive a slight decrease in noise, and 8 which would receive a large decrease in noise.





Significance


= 0 21 21 Neutral

0.1 - 0.9 0 36 Neutral

1 - 2.9 0 6 Slight


>=5 0 8 Large

Total >1 0 16

Total >3 0 10





Significance


= 0 18 18 Neutral

0.1 - 0.9 0 39 Neutral

1 - 2.9 0 6 Slight


>=5 0 8 Large

Total >1 0 16

Total >3 0 10







Significance


= 0 34 34 Neutral

0.1 - 0.9 0 64 Neutral

1 - 2.9 0 5 Slight


>=5 0 0 Large

Total >1 0 5

Total >3 0 0

Table E.96 - Results for introducing 202m of 1.5m noise barrier to the east of the road




Significance


= 0 43 43 Neutral

0.1 - 0.9 1 55 Neutral

1 - 2.9 0 4 Slight


>=5 0 0 Large

Total >1 0 4

Total >3 0 0





Significance


= 0 65 65 Neutral

0.1 - 0.9 1 37 Neutral

1 - 2.9 0 0 Slight


>=5 0 0 Large

Total >1 0 0

Total >3 0 0


E.12.15 This shows that all of the changes in noise are neutral.





Significance


= 0 1 1 Neutral

0.1 - 0.9 0 50 Neutral

1 - 2.9 0 40 Slight


>=5 0 4 Large

Total >1 0 52

Total >3 0 12

Table E.99 - Results for introducing 202m of 4m noise barrier to the east of the road

E.12.16 This shows that there are 40 properties which would receive a slight decrease in noise, 8 which would receiver a moderate decrease in noise, and 4 which would receive a large decrease in noise.



Significance


= 0 2 2 Neutral

0.1 - 0.9 0 76 Neutral

1 - 2.9 0 21 Slight


>=5 0 3 Large

Total >1 0 25

Total >3 0 4


E.12.17 This shows that there are 21 properties which would receive a slight decrease in noise, 1 which would receiver a moderate decrease in noise, and 3 which would receive a large decrease in noise.





Significance


= 0 28 28 Neutral

0.1 - 0.9 0 71 Neutral

1 - 2.9 0 4 Slight


>=5 0 0 Large

Total >1 0 4

Total >3 0 0


E.12.18 This shows that there are 4 properties which would receive a slight decrease in noise,



benefit

Economic cost of

measure

Net improvement

280m of 1.5m barrier to the east £25k £101k -£76k

280m of 2m barrier to the east £65k £126k -£61k





178m of 1.5m barrier to the west £36k £64k -£28k

178m of 2m barrier to the west £49k £80k -£31k














E.13 Case Study 12

E.13.1 36 properties were considered on both sides of the track in a small area, 16 on one side and 20 on the other. 180m of reflective barrier was installed on one side and 150m on the other. Barrier increments were tested in 0.5m steps between 1.5m and 3m.

Change in noise level LAeq,18h


Significance


= 0 0 0 Neutral

0.1 - 0.9 0 15 Neutral

1 - 2.9 0 21 Slight


>=5 0 0 Large

Total >1 0 21

Total >3 0 0

Table E.103 - Results for 1.5m barriers – high speed trains



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight

3 - 4.9 0 36 Moderate

>=5 0 0 Large

Total >1 0 36

Total >3 0 36

Table E.104 - Results for 1.5m barriers – low speed trains

E.13.2 This shows that the increased source height of the diesel locomotives reduces the effectiveness

of the noise barriers.





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 24 Slight

3 - 4.9 0 12 Moderate

>=5 0 0 Large

Total >1 0 36

Total >3 0 12

Table E.105 - Results for 2m barriers – high speed trains



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight

3 - 4.9 0 10 Moderate

>=5 0 26 Large

Total >1 0 36

Total >3 0 36

Table E.106 - Results for 2m barriers – low speed trains



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 20 Slight


>=5 0 8 Large

Total >1 0 36

Total >3 0 16

Table E.107 - Results for 2.5m barriers – high speed trains





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight


>=5 0 36 Large

Total >1 0 36

Total >3 0 36

Table E.108 - Results for 2.5m barriers – low speed trains



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight

3 - 4.9 0 24 Moderate

>=5 0 12 Large

Total >1 0 36

Total >3 0 36

Table E.109 - Results for 3m barriers – high speed trains



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 0 Slight


>=5 0 36 Large

Total >1 0 36

Total >3 0 36

Table E.110 - Results for 3m barriers – low speed trains

E.13.3 These results have been monetised and the costs for the different measures estimated, and these

results are shown in the following table:




of acoustic benefit

Economic cost of

measure

Net improvement

1.5m reflective barrier – low speed £227k £99k +£128k

2m reflective barrier – low speed £313k £124k +£189k

2.5m reflective barrier – low speed £402k £149k +£253k

3m reflective barrier – low speed £504k £173k +£331k

1.5m reflective barrier – high speed £47k £99k -£52k

2m reflective barrier – high speed £71k £124k -£53k

2.5m reflective barrier – high speed £253k £149k +£104k

3m reflective barrier – high speed £273k £173k +£100k


E.14 Case Study 13

E.14.1 63 properties were considered. 36 on the south side of the rail line and 27 to the north. Tests were undertaken introducing a 350m barrier to the south.



Significance


= 0 0 0 Neutral

0.1 - 0.9 27 1 Neutral

1 - 2.9 0 3 Slight


>=5 0 27 Large

Total >1 0 35

Total >3 0 32

Table E.112 - Results for introducing 2m reflective noise barrier to the south

E.14.2 This shows that there is an imperceptible increase in noise at the 27 properties to the north, and decreases in noise at the 36 properties to the south.





Significance


= 0 0 0 Neutral

0.1 - 0.9 27 1 Neutral

1 - 2.9 0 1 Slight


>=5 0 32 Large

Total >1 0 35

Total >3 0 34




Significance


= 0 0 0 Neutral

0.1 - 0.9 27 0 Neutral

1 - 2.9 0 1 Slight


>=5 0 34 Large

Total >1 0 36

Total >3 0 35


E.14.3 These results show that increasing the height of the barrier improves the decreases in noise to the south, but has no effect on the properties to the north.

E.14.4 The tests were repeated with an absorbent barrier:



Significance


= 0 21 21 Neutral

0.1 - 0.9 6 1 Neutral

1 - 2.9 0 3 Slight


>=5 0 27 Large

Total >1 0 35

Total >3 0 32

Table E.115 - Results for introducing 2m absorptive noise barrier to the south





Significance


= 0 21 21 Neutral

0.1 - 0.9 6 1 Neutral

1 - 2.9 0 1 Slight


>=5 0 32 Large

Total >1 0 35

Total >3 0 34




Significance


= 0 21 21 Neutral

0.1 - 0.9 6 0 Neutral

1 - 2.9 0 1 Slight


>=5 0 34 Large

Total >1 0 36

Total >3 0 35


E.14.5 These results show that the reflections from the barrier on the properties to the north are greatly reduced.



benefit

Economic cost of

measure

Net improvement

2m reflective barrier £283k £131k +£152k



2m absorbent barrier £283k £219k +£64k






E.15 Case Study 14

E.15.1 Calculations were undertaken to assess the impact of the addition of a barrier to the west of the railway line. Calculations were undertaken based on barrier heights of between 1.5m to 4m, in 0.5m increments. Each scenario was assessed for both high-speed and slow-speed rail scenarios.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 10 Neutral

1 - 2.9 0 105 Slight

3 - 4.9 0 52 Moderate

>=5 0 0 Large

Total >1 0 157

Total >3 0 52

Table E.119 - Results for 330m of 1.5m barrier to west (high speed)

E.15.2 This shows that there are 105 properties which would receive a slight decrease in noise, and 52 properties which would receive a moderate decrease in noise.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 4 Neutral

1 - 2.9 0 64 Slight

3 - 4.9 0 92 Moderate

>=5 0 7 Large

Total >1 0 163

Total >3 0 99

Table E.120 - Results for 330m of 2m barrier to west (high speed)

E.15.3 This shows that there are 64 properties which would receive a slight decrease in noise, 82

properties which would receive a moderate decrease in noise and 7 properties which would receive a large decrease in noise.





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 2 Neutral

1 - 2.9 0 43 Slight

3 - 4.9 0 80 Moderate

>=5 0 42 Large

Total >1 0 165

Total >3 0 122


E.15.4 This shows that there are 43 properties which would receive a slight decrease in noise, 80 properties which would receive a moderate decrease in noise and 42 properties which would receive a large decrease in noise.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 1 Neutral

1 - 2.9 0 30 Slight

3 - 4.9 0 57 Moderate

>=5 0 79 Large

Total >1 0 166

Total >3 0 136


E.15.5 This shows that there are 30 properties which would receive a slight decrease in noise, 57

properties which would receive a moderate decrease in noise and 79 properties which would receive a large decrease in noise.





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 18 Slight

3 - 4.9 0 37 Moderate

>=5 0 112 Large

Total >1 0 167

Total >3 0 149





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 12 Slight

3 - 4.9 0 30 Moderate

>=5 0 125 Large

Total >1 0 167

Total >3 0 155







Significance


= 0 0 0 Neutral

0.1 - 0.9 0 26 Neutral

1 - 2.9 0 96 Slight

3 - 4.9 0 45 Moderate

>=5 0 0 Large

Total >1 0 141

Total >3 0 45

Table E.125 - Results for 330m of 1.5m barrier to west (slow speed)

E.15.8 This shows that there are 96 properties which would receive a slight decrease in noise, and 45 properties which would receive a moderate decrease in noise.



Significance


= 0 0 0 Neutral

0.1 - 0.9 0 5 Neutral

1 - 2.9 0 65 Slight

3 - 4.9 0 90 Moderate

>=5 0 7 Large

Total >1 0 162

Total >3 0 97

Table E.126 - Results for 330m of 2m barrier to west (slow speed)






Significance


= 0 0 0 Neutral

0.1 - 0.9 0 3 Neutral

1 - 2.9 0 47 Slight

3 - 4.9 0 80 Moderate

>=5 0 37 Large

Total >1 0 164

Total >3 0 117





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 1 Neutral

1 - 2.9 0 34 Slight

3 - 4.9 0 60 Moderate

>=5 0 72 Large

Total >1 0 166

Total >3 0 132







Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 26 Slight

3 - 4.9 0 36 Moderate

>=5 0 105 Large

Total >1 0 167

Total >3 0 141





Significance


= 0 0 0 Neutral

0.1 - 0.9 0 0 Neutral

1 - 2.9 0 13 Slight

3 - 4.9 0 32 Moderate

>=5 0 122 Large

Total >1 0 167

Total >3 0 154







of acoustic benefit

Economic cost of

measure

Net improvement

1.5m barrier to the west (high speed) £674k £99k +£575k

2m barrier to the west (high speed) £963k £124k +£839k





1.5m barrier to the west (slow speed) £570k £99k +£471k

2m barrier to the west (slow speed) £754k £124k +£630k






E.16 Case Study 15

E.16.1 Calculations were undertaken to assess the impact of the addition of a barrier to the south of the railway line, and the addition of barriers to both the north and south of the railway line. Calculations were undertaken based on barrier heights of 2m and 4m, and each scenario was assessed for both high-speed and slow-speed rail scenarios.



Significance


= 0 193 193 Neutral

0.1 - 0.9 1658 65 Neutral

1 - 2.9 0 119 Slight

3 - 4.9 0 22 Moderate

>=5 0 3 Large

Total >1 0 144

Total >3 0 25

Table E.132 - Results for introducing a 2m noise barrier to the south of the railway line (slow-speed service)

E.16.2 This shows that there are 119 properties which would receive a slight decrease in noise, 22 would

receive a moderate decrease in noise and 3 would receive a large decrease in noise.





Significance


= 0 707 707 Neutral

0.1 - 0.9 1175 175 Neutral

1 - 2.9 0 3 Slight


>=5 0 0 Large

Total >1 0 3

Total >3 0 0

Table E.133 - Results for introducing a 2m noise barrier to the south of the railway line (high-speed service)




Significance


= 0 159 159 Neutral

0.1 - 0.9 1671 23 Neutral

1 - 2.9 0 40 Slight

3 - 4.9 0 92 Moderate

>=5 0 75 Large

Total >1 0 207

Total >3 0 167

Table E.134 - Results for introducing a 4m noise barrier to the south of the railway line (slow-speed service)






Significance


= 0 522 522 Neutral

0.1 - 0.9 1317 104 Neutral

1 - 2.9 0 111 Slight


>=5 0 2 Large

Total >1 0 117

Total >3 0 6

Table E.135 - Results for introducing a 4m noise barrier to the south of the railway line (high-speed service)

E.16.5 This shows that there are 111 properties which would receive a slight decrease in noise, 4 would

receive a moderate decrease in noise and 2 would receive a large decrease in noise.



Significance


= 0 252 252 Neutral

0.1 - 0.9 588 847 Neutral

1 - 2.9 8 315 Slight

3 - 4.9 0 46 Moderate

>=5 0 4 Large

Total >1 8 365

Total >3 0 50

Table E.136 - Results for introducing 2m noise barriers to the north and south of the railway line (slow-speed service)

E.16.6 This shows that there are 8 properties which would receive a slight increase in noise. There are 315 properties which would receive a slight decrease in noise, 46 would receive a moderate decrease in noise and 4 would receive a large decrease in noise.





Significance


= 0 623 623 Neutral

0.1 - 0.9 308 1119 Neutral

1 - 2.9 0 10 Slight


>=5 0 0 Large

Total >1 0 10

Total >3 0 0

Table E.137 - Results for introducing 2m noise barriers to the north and south of the railway line (high-speed service)




Significance


= 0 139 139 Neutral

0.1 - 0.9 240 220 Neutral

1 - 2.9 112 837 Slight

3 - 4.9 20 302 Moderate

>=5 22 168 Large

Total >1 154 1307

Total >3 42 470

Table E.138 - Results for introducing 4m noise barriers to the north and south of the railway line (slow-speed service)

E.16.8 This shows that there are 112 properties which would receive a slight increase in noise, 20 would

receive a moderate increase in noise and 22 would receive a large increase in noise. There are 837 properties which would receive a slight decrease in noise, 302 would receive a moderate decrease in noise and 168 would receive a large decrease in noise.





Significance


= 0 274 274 Neutral

0.1 - 0.9 142 1257 Neutral

1 - 2.9 0 362 Slight

3 - 4.9 0 23 Moderate

>=5 0 2 Large

Total >1 0 387

Total >3 0 25

Table E.139 - Results for introducing 4m noise barriers to the north and south of the railway line (high-speed service)




benefit

Economic cost of

measure

Net improvement

2m barrier to the south (slow-speed) -£194k £193k -£387k

2m barrier to the south (high-speed) -£108k £193k -£301k

4m barrier to the south (slow-speed) £235k £399k -£164k

4m barrier to the south (high-speed) £152k £399k -£247k

2m barriers to the north and south (slow-speed)

£372k £379k

-£7k

2m barriers to the north and south (high- speed)

£414k £379k

+£35k

4m barriers to the north and south (slow-speed)

£2,069k £784k

+£1285k

4m barriers to the north and south (high- speed)

£1,916k £784k

+£1132k

Table E.140 – Monetised results and estimates of costs for different measures



Appendix F - Review of Sound

Insulation Performance of

Windows



F.1 Introduction

F.1.1 This appendix reviews the acoustic performance of different types of window.

F.2 PPG24 1994 – Annex 6

F.2.1 Because the sound insulation of a window (and other components of the building envelope) varies with the frequency (or pitch) of the sound, the overall noise reduction provided by a window will depend, among other factors, on the spectrum of the external noise. Table 1 in Annex 6 of this document99 shows typical reductions in noise levels from common sources which would be expected from various types of window installations fitted in brick/block walls in a dwelling. The insulation provided by any type of window when partially open will be in the region of 10-15 dB (A). This table is repeated below;

Noise Source Single glazing Thermal double glazing Secondary glazing

Road traffic 28 33 34

Civil aircraft 27 32 35

Military aircraft 29 35 39

Diesel train 28 32 35

Electric train 30 36 41

Table F.1 - Difference between dB(A) levels outside and inside (PPG24 Annex 6 Table 1)

F.2.2 The values in the Table are the difference between dB(A) levels measured outside and inside typical dwellings; they have not been corrected for reverberation time or window area, and so cannot be compared with values obtained under other conditions. The Table is intended to give an idea of the insulation likely to be achieved in practice - not under ideal conditions. Secondary glazing systems in particular will perform better in installations where sound insulation is not limited by poor sealing or by flanking sound paths such as through doors or acoustically weak parts of window bays. The values for single glazing are representative of well sealed windows.

F.2.3 Ventilators of the type specified in the Noise Insulation Regulations will limit the overall sound insulation against traffic noise to about 38 dB(A).

F.3 BB93 – Section 3.4

F.3.1 For partially open single-glazed windows or double-glazed windows with opposite opening panes, 100

the laboratory measured airborne sound insulation is approximately 10-15 dB Rw . This

increases to 20-25 dB Rw in the open position for a secondary glazing system with partially open ventilation openings, with the openings staggered on plan or elevation, and with absorbent lining of the window reveals. In situ, the degree of attenuation provided by an open window also depends on the spectrum of the noise and the geometry of the situation.

F.4 BB101 – Section 4.3.1

F.4.1 Noise from road vehicles, rail and air traffic, is often cited as a major constraint on the use of natural ventilation101. For an external-free-field A-weighted noise level dominated by road traffic, facades with typical manually controlled open windows attenuate the noise into a classroom with 0.5 second reverberation time by between 8 dB and 14 dB. Therefore the external free-field noise should not exceed 49 dB(A) for the indoor noise level to be below 35 dB(A).

F.4.2 Automatically controlled windows, and other vents that allow close control of the open area, can provide considerably better sound attenuation of up to 20 dB(A) - 30 dB(A). If classrooms are



located on the noisy facades, normal manually opening windows might not be possible, but automatically or other closely controlled windows, roof-mounted ventilators or sound-attenuated openings might be an option.

F.5 BS8233: 1999 – Section 8.4.7

F.5.1 Table 10 in this document102 gives guide values for the sound insulation of windows, as measured in the field. The table is repeated below;

Description Weighted sound reduction index Rw dB

Any type of window in a frame when partially open 10-15

Single glazed windows (4mm glass) 22-30

Thermal insulating units (6-12-6) 33-35

Secondary glazed windows (6-100-6) 35-40

Secondary glazed windows (4-200-4) 40-45

Table F.2 – Sound insulation of typical windows (BS8233 Table 10)

F.6 BS8233: 1999 – Section 6.7.1

F.6.1 For simple calculations, the performance of windows can be approximated by the Rw values. Therefore if external noise levels are 67dB and thermal windows are assumed to have an Rw of 33dB, the internal noise levels would be 34dB (67 - 33).

F.7 BRE Information Paper IP 6/94 – The sound Insulation Provided by Windows

F.7.1 A range of window types have been tested in a standard transmission suite using commercially available window frames fitting the opening 1.76m by 1.19m103. Some tests were also undertaken from an anechoic room to a reverberant room to simulate an outdoor to indoor propagation.

Frame material

Pane size

Seal type Primary pane

Secondary glazing Rw

Wood Large Normal 4mm - 30

Wood Large Normal 4-6-4 - 32

Wood Large Normal 6-12-6 - 34

Wood Large Normal 4mm 150mm gap, 4mm 42

Wood Large Normal 4mm 300mm gap, 4mm 47

Wood Large Normal 6-12-6 150mm gap, 4mm 46

Wood Large Normal 6-12-6 300mm gap, 4mm 52

Wood Large Normal 4mm 150mm gap + liner, 4mm 44

Wood Large Normal 4mm 300mm gap + liner, 4mm 51

Wood Large Good 6-12-6 - 34

PVC-U Large Normal 6-12-6 - 35



PVC-U Large Poor 6-12-6 150mm gap, 4mm 33

Wood Small Normal 4mm - 29

Table F.3 – Sound insulation provided by windows (BRE IP 6/94 Table 1)

F.7.2 The paper concludes that the sound insulation performance of windows is very dependent on the quality of the sealing and that the frame material is not important providing the sealing is adequate. It also concludes that multiple panes of glass improve insulation, and the greater the space between the panes the better, and sealing may be the limiting factor,

F.7.3 Several small panes of glass were shown to give a slightly improved insulation at lower frequencies when compared with a large pane of similar area. Absorbent reveals (‘+ liner’ in the table above) between the glazing panes were shown to be beneficial at higher frequencies.

F.7.4 It is commented that trickle vents have little adverse effect on single glazed windows, but they can limit the performance of thermal double glazed units. It is commented that a properly designed system should be used where ventilation and high sound insulation are required.

F.8 BRE Digest 338

F.8.1 This paper identifies in its Table 1104 the level difference of different windows types in dwellings, based on field measurements. The text indicates that the window is approximately 1/3 of the wall, and that the reverberation time in the room is approximately 0.3s.

Description Level difference (average 100-3150Hz)

Small window (e.g. nightlight) partly open 15 dB

Single wooden casement (4mm glass) 28 dB

Thermal double glazed unit 33 dB

Secondary double window (air gap 150-200mm) 37 dB

Table F.4 – Level difference for different window types (BRE 338 Table 1)

F.8.2 The paper indicates that indoor levels can be assessed by the subtraction of the average level difference, based on an approximate empirical relationship.

F.8.3 Table 2 in the report sets out difference in dB for traffic noise and it notes that the actual performance of secondary glazing units is lower than would be expected by using the level difference. The paper explains that this is due to the predominance of low frequencies in road noise and that there can be a dip in the performance of these windows at low frequencies.

Description Level difference dB(A)

Single wooden casement (4mm glass) 28 dB

Thermal double glazed unit 33 dB

Secondary double window (air gap 150-200mm) 34 dB

Table F.5 – Level difference for different window types (BRE 338 Table 2)

F.8.4 The paper outlines that if windows are open, only the area of the opening is significant. If this is 10% of the total area, the noise reduction will be 10dB whatever the type of window or wall construction.

F.9 BRE Digest 379

F.9.1 This paper outlines in its table 3105, measurements of sound insulation for different types of window. Ranges of values are given, with the upper end of the range coming from laboratory



measurements, and it notes that these are unlikely to be achieved in practice due to sealing requirements. Values from the lower end of the range are described as more typical. It is noted that well fitted thermal windows with compressible seals around openable lights can provide insulation approaching laboratory values.

Type of window Rw dB RA(traffic) dB

Open window (any type of small casement window open at about 45°for ventilation)

About 10 About 10

Single glazing (4mm single glazed window) 22-30 22-28

Thermal glazing (thermal 6-12-6 unit in PVC-U frame) 33-35 26-29

Secondary glazed windows (openable secondary system 4- 200-4 with absorbent reveals)

40-45 36-41

Table F.6 - Laboratory measurements of sound insulation for different types of windows (BRE 379 Table 3)

F.10 BS6262 – Glazing for Buildings, Part 2 – Code of Practice for Energy, Light and Sound (2005)

F.10.1 This standard gives Rw performance for various types of glazing presented below, from Tables 12 and 13 in this standard.

106. Extracts of this data is

Description Rw

4mm single glazing 29




4-12-4 double glazing 29





6-100-4 secondary glazing 46



Table F.7 – Sound insulation for different glazing (Extracts from BS6262 Tables 12 & 13)

F.11 BRE Domestic Energy Fact File (2006)

F.11.1 This paper provides details on the proportion of properties with double glazing, based on data from GfK Home Audit107. 2004 is the last year of data available, and this indicates that some 83% of properties have double glazing. Of these properties further information is given about the proportion of rooms with double glazing, as shown in the following table. The paper indicates that the confidence interval for the data is +/- 0.8%.



Rooms with double glazing. Percentage (of properties with double

glazing)

>80% of rooms with double glazing 52%

>60% of rooms with double glazing 65%

<60% of rooms with double glazing 9%

Proportion of rooms not stated 26%

Table F.8 – Proportion of rooms with double glazing

(Data from Domestic Energy Factfile)

F.11.2 If we assume that the properties where the proportion of rooms with double glazing is not stated is distributed the same as the other properties, then we identify that some 15% of all properties have double glazing in at between 60% and 80% of their rooms and 58% of all properties have double glazing in at least 80% of their rooms.

F.11.3 Conversely there are some 17% of properties with no double glazing, and some 10% of properties with double glazing in less than 60% of their rooms.

F.11.4 If we further assume that people are more likely to provide double glazing to their living rooms and bedrooms than their kitchens, bathrooms and circulation spaces, then this indicates that properties with at least 80% of their rooms having double glazing will have treated all living and bedrooms.

F.11.5 This allows us to identify the approximate scope for potential improvements in building envelopes through changing to double glazed windows.

Proportion of properties

No double glazing – strong potential for improvements 17%

Limited double glazing – potential for improvements in some rooms

10%

Double glazing in many rooms – small potential for improvement

15%

Double glazing in most rooms – minimal potential for improvements

58%

Table F.9 – Proportion of properties with potential for improvement

(Data from Domestic Energy Factfile)

F.12 BRE Report 162 – Background Ventilation of Dwellings: a Review (1989)

F.12.1 This report outlines the six main methods for providing background ventilation in dwellings, but statistics are not provided for the proportion of the different methods108. Five of the six methods require either supply or extraction of air through openings in the building fabric including air bricks, trickle ventilators and openable windows.

F.12.2 Only properties with balanced mechanical ventilation systems are identified as having supply and extraction through purpose built openings, therefore eliminating the need to open windows to provide background ventilation. The text of the report is written as though this type of system is rare in the UK.



F.12.3 The report identifies that with naturally ventilated systems during the summer, large openable areas are required to introduce ‘copious ventilation’.

F.13 Summary of Glazing Performance

F.13.1 A summary of the following performance data is presented:

Table F.10 – Summary glazing performance.

Glazing System Performance range (units are Rw, RA(traffic), DdBA or D100-3150Hz)

Typical value

Partially open window 8 to 15 10 or 15

Partially open secondary glazing system 20 to 25 20 or 25

Single glazed window – closed 22 to 34 28

Double glazed window – closed 26 to 36 33

Secondary glazing – closed (unspecified) 34 to 41 35

Secondary glazing – closed (both single glazed) 35 to 51 42

Secondary glazing – closed (single with double glazed) (33 with poor sealing) 46 to 52 46 or 52

F.13.2 This data has been used to derive the benefits from changing from one glazing system to another. BS8233 advises that for simple calculations the level difference of a window can be approximated by the Rw of the window, and therefore, all of the data presented above can be used in determining the benefits.

Single Glazing

F.13.3 For single glazing, BRE IP 6/94 indicates that trickle vents play little part in the overall performance. PPG24 indicates that the single glazed figures are for well sealed windows, and BRE Digest 379 indicates that values in practice would be at the lower end of the ranges it quotes. This paper also indicates that if the window is well sealed, then values approaching the laboratory performance can be realised.

F.13.4 There is ample data to indicate the performance improvements when replacing single glazed windows with double glazed windows. Typically, the difference between the performance of single and double glazed windows is around 5dB. In reality, the performance of single glazed windows may perform lower than typical, and the benefit may actually be greater than this.

F.13.5 If the measure is to add ventilation to a single glazed system, this would entail ensuring that the windows are well sealed, and the improvement can be estimated by looking at the range of single glazed windows. Overall, there is a 12dB range across all papers. Of course, it must be borne in mind that the provision of ventilation would eliminate the need to open windows or trickle vents for ventilation, and therefore the performance improvement would be the change from a 10-15dB for partially open window, to the upper end of the 22-34dB range for a well sealed single glazed window. 15dB would be a conservative assessment here.

F.13.6 The data from BB93 indicates that the overall performance of a partially open single glazed windows would improve by around 10dB when adding a secondary glazing and allowing the windows to opened for ventilation.

F.13.7 There is ample data to indicate the performance of adding a secondary glazing system to single glazed windows. The secondary glazing test data is based on closed windows, and would assume that ventilation is provided by another means. We would typically expect the performance of the single glazed window to be at the lower end of the 22 to 34dB range, or lower with partially open windows. The performance of the completed system would be expected to be in middle of the 34



to 51dB range as we would probably exclude the highest performances with the largest air gaps, and the lowest performances with the poorest sealing - 42dB was typically quoted. Therefore, an improvement of 20dB would be a reasonable assumption, although this is conservative if the existing single glazed system is required to open for ventilation.

F.13.8 If the measure is to replace the single glazing with double glazing and add ventilation to prevent the requirement for the windows to be openable, then the improvement would be from the 10- 15dB range for partially open windows to the upper end of the 26-36dB range. An improvement of 20dB would be a conservative assumption.

Double Glazing

F.13.9 For double glazed windows, BRE Digest 379 indicates that the performance of double glazed windows is limited by sealing, and values towards the lower end of the ranges quotes are more typical of what would be achieved in practice. BRE IP 6/94 also indicates that the performance of double glazed windows is limited by trickle vents. BRE Digest 379 indicates that if the window is well sealed, then values approaching the laboratory performance can be realised.

F.13.10 If the measure is to add ventilation to prevent the requirement for windows to be openable, then the improvement would be from the 10-15dB for partially open windows to the lower end of the 26- 36dB range, assuming that trickle vents limit the existing performance. An improvement of 15dB would be a conservative assumption.

F.13.11 There is limited data available to illustrate the performance of adding a secondary glazing and ventilation to an existing double glazed system. On the basis that double glazing typically performs 5dB better than single glazing, the benefit for this measure is therefore 5dB lower than the equivalent measure for a single glazed window.

Secondary Glazing

F.13.12 If the location already has a secondary glazing system, then the key improvement would be to provide ventilation, preventing the need to open the windows and to improve sealing. There is limited data available to assess this, but the improvement is likely to be from the BB93 20-25 for partially open secondary glazing to middle of 34-52dB range. This improvement should also have a lower performance than from standard single glazing, and an improvement of 15dB has been assumed.

Sealed Systems

F.13.13 If the building already has a sealed system with ventilation, then this is likely to be performing at the upper end of the ranges quoted. Therefore, if the building has this system with double glazing, then it is not likely that a significant improvement could be made, however there are benefits from changing from single to double glazing, and a 5dB improvement has been taken for this situation. This type of system is rare in the UK.

Benefits Summary

F.13.14 The different benefits described above have been summarised into the following table:

Table F.11 – Summary of Assumed Acoustic Benefits for Window Improvements

Existing Glazing

Existing Ventilation

Proposed Glazing Proposed Ventilation Improvement

Single Glazing Trickle vent – window closed

Replace with Double Glazing

No change – window closed

5 dB

Single Glazing Window partly open Add Secondary Glazing

No change – window partly open

10 dB

Single Glazing Window partly open No change Provide Alternative means – window closed

15 dB



Single Glazing Window partly open Replace with Double

Glazing Provide Alternative means – window closed

20 dB

Single Glazing Window partly open Add Secondary Glazing

Provide Alternative means – window closed

20 dB

Double Glazing Window partly open No change Provide Alternative means – window closed

15 dB

Double Glazing Window partly open Add Secondary Glazing

Provide Alternative means – window closed

15 dB

Secondary Glazing

Window partly open No change Provide Alternative means – window closed

15 dB

Sealed Single Alternative means – window closed

Replace with Sealed Double Glazing

No change 5 dB

Sealed Double Alternative means – window closed

None required No change 0 dB

F.13.15 Practically, exchanging single glazing for double glazing is likely to give an improvement of some 4-5dB in the acoustic performance, depending on the type and condition of the existing single glazed windows.

F.13.16 Adding secondary glazing to an existing single glazed window is likely to improve the acoustic performance by 6-10dB. Adding secondary glazing to existing double glazing has not been tested in the papers reviewed.

F.13.17 The overall performance of some single glazed secondary glazing systems is broadly similar to some double glazed systems.

F.13.18 Providing an alternative means of ventilation, allowing single glazed windows to remain closed can improve noise levels by at 7dB-12dB adopting a conservative standpoint, but potentially improvements up to 20dB are possible provided windows are well sealed, and where the previous opening was at least 10% of the window area. The equivalent improvements, allowing double glazed windows to remain closed is in the range 15-20dB.

F.13.19 In real situations, the acoustic performance of windows will be limited by the sealing and the

presence of any trickle ventilators:

• Single glazed windows are likely to perform 6-8dB lower than laboratory test results

• Double glazed windows are likely to perform 2-3dB lower than laboratory test results

• Secondary glazing systems are likely to perform 5-6dB lower than laboratory test results.

99 Planning Policy Guidance note 24 (PPG24) Annex 6, Department of the Environment, Sept. 1994.

100 Building Bulletin 93 Acoustic Design of Schools a Design Guide (BB93), Department for education and skills, Nov 2003.

101 Building Bulletin 101 Ventilation of school buildings (BB101), Department for Children,

Schools and Families, July 2006

102 British Standard 8233 Sound insulation and noise reduction for buildings – Code of practice; 1999 (BS8233), BSi



103 BRE Information Paper IP 6/94 – The sound Insulation Provided by Windows, Building

Research Establishment, NJ Tinsdeall, 1994 104 BRE Digest 338 Insulation against external noise, Building Research Establishment,

November 1998 105 BRE Digest 379 Double glazing for heat and sound insulation, Building Research

Establishment, February 1993

106 British Standard 6262 – Glazing for Buildings, Part 2 – Code of Practice for Energy, Light and Sound; 2005 (BS6262), BSi

107 BRE Domestic Energy Fact File (2006) Owner occupied, Local authority, Private rented

and Registered social landlord homes, Building Research Establishment, JI Utley and LD Shorrock, 2006

108 BRE Report 162 – Background Ventilation of Dwellings: a Review, Building Research Establishment, Christine E Uglow, 1989



Appendix G Planning

Legislation



G.1 Introduction

G.1.1 This appendix provides further background on the likelihood for planning approvals for noise control measures.

G.2 Planning Legislation and Process

G.2.1 Planning Legislation and Regulation is not uniform across the whole of the UK. Although there are areas of commonality, the planning system in Scotland and Northern Ireland in particular can be significantly different from that operated in England and Wales. For this reason, the Planning matters described in this appendix assume that the proposed noise control measures will be undertaken within England and Wales only. Further, the planning information given should not be taken to constitute a legal opinion or interpretation of the law.

G.2.2 It should be noted that some of the noise control measures outlined in this report fall outside the scope of planning control i.e. planning permission is not required. In such cases the normal best practice would be to inform the local planning authority about the proposal/works prior to them being undertaken.

G.2.3 Whether a proposal /works falls within the scope of planning control (for which planning permission, or ‘prior written approval’ from the local planning authority is required prior to the commencement of the works) is broadly determined by the following considerations:

• If the proposal/works fall within the definition of ‘Development’ (under the Town & Country Planning Act 1990) (as amended).

• If the proposal/works are considered ‘Permitted Development’ (under the Town & Country [General Permitted Development] Order 1995 (as amended).

• If the proposal/works are prohibited by a condition attached to a previous planning permission, enforcement notice, or Special Development Order (a site specific consideration).

• If the local planning authority (LPA) has imposed restrictions to remove the normal permitted development rights (known as Article 4, and Article 6 Direction) (a site specific consideration).

G.2.4 The following flow diagram sets out the general circumstances which would dictate if the proposal /works require planning consent (through grant of planning approval by the appropriate Local Planning Authority). If in doubt however the developer would be best advised to contact the local planning authority for confirmation as to whether planning permission would be required. Further clarification is given in the text below.


4


Figure G.1 - Requirement for Planning Consent or prior written approval from the Local Planning Authority

Proposal/ works

Does the proposal /works require Environmental Impact Assessment2, or constitute a highway danger?

Yes Is the proposal defined as ‘Development’1? No Planning consent not required

(but suggest that LPA be informed prior to commencement

Yes No

Is the proposed development classed as ‘Permitted

Development’ under the various Parts of the GDPO2 Schedule 2)?

Yes

Is the proposal/works prohibited by an Enforcement Notice5 or Special Development Order6, or within a site in which conditions to a

Planning Consent remove Permitted Development rights?

Is the proposed

No development within a site covered by ‘Article

4’7 or ‘Article 6’8

Is ‘Prior Approval’3/

No ‘Written Notification’ No needed?

Yes

Yes No

Yes

Development does not constitute Permitted

Development, therefore Planning Consent required

Submit details to L.P.A. who will either approve the submitted details, or confirm that Planning Consent is

required

Planning Consent may be required, or the

Discharge/Variation of Condition

Planning Consent required

Planning Consent not

required



G.2.5 The following notes refer to the diagram above:

- 1 As defined within the Town and Country Planning Act 1990 (as amended)

- 2 Projects which are judged likely to have significant environmental effects require an Environmental Impact Assessment to be carried out as detailed in Directive 85/337/EEC as amended by Directive 97/11/EC. Further information can be found within the publication ‘Environmental Impact Assessment: A guide to procedures’ (January 2000).

- 3 Schedule 2 of the GDPO requires the prior approval of the Local Planning Authority for some development.

- 4 Written Notification as required under the ’Conservation (Natural Habitats, &C.)’ Regulations 1994 (S.I. 1994/No. 2716) (as amended).

- 5 An enforcement notice may be served if planning authorities consider that there has been a breach of planning control. It specifies remedial action that must be taken to remedy the breach of control, within a deadline, by making the development comply with the terms of a planning permission, by discontinuing any use or by restoring the land to its condition before the breach took place; or remedy any injury to amenity which has been caused by the breach. Failure to comply with an enforcement notice is an offence

- 6 There is under the GDPO a provision for the Secretary of State to make a ‘Special Development Order’ specifying Permitted Development rights according to specific locations or categories of development.

- 7 The Town and Country Planning (General Permitted Development) Order 1995 (S.I. 1995/No. 418: ’Directions restricting permitted development’. By a direction made under this article, a local planning authority can restrict the scope of the permitted development rights in relation to defined areas. It is a power of pre-emption rather than prohibition: by withdrawing the deemed permission under this Order, its effect is to require an application to be made for express permission for development proposals

- 8 The Town and Country Planning (General Permitted Development) Order 1995 (S.I. 1995/No. 418: ‘Notice and confirmation of article 4(2) directions’. This article prescribes the procedures to be followed for the making of those article 4(2) directions which do not require the approval of the Secretary of State.

Defining ‘Development’

G.2.6 The Town and Country Planning Act 1990 (as amended) defines the meaning of ‘development’:

“Subject to the following provisions of this section, in this Act , except where the context otherwise requires, “development,” means the carrying out of building, engineering, mining or other operations in, on, over or under land, or the making of any material change in the use of any buildings or other land”.

G.2.7 There however a number of exceptions and clarifications to this definition, including:

“The following operations or uses of land shall not be taken for the purposes of this Act to involve development of the land—

(a) the carrying out for the maintenance, improvement or other alteration of any building of works which—

(i) affect only the interior of the building, or (ii) do not materially affect the external appearance of the building”

“(b) the carrying out on land within the boundaries of a road by a local highway authority of any works required for the maintenance or improvement of the road [but, in the case of any such works which are not exclusively for the maintenance of the road, not including any works which may have significant adverse effects on the environment]”



G.2.8 It can be assumed that any planned works that do not constitute ‘development’ under this

definition (accounting for its caveats) shall not require planning consent.

Permitted Development

G.2.9 ‘Permitted development’ is development that can be undertaken without the need for a specific planning consent from the local planning authority. The overarching regulation that defines those types of developments that do and do not require planning permission is contained within the Town and Country Planning (General Permitted Development) Order 1995 (as amended) (the ‘GPDO’).

G.2.10 In some specific instances, there will be a requirement for a developer in the first instance to summit to the local authority details of the scheme before commencing the works. This is generally known as the ‘prior approval’ procedure. In addition, there will always be the need for the developer to receive written notification of the approval of the local planning authority for works that affect certain sites protected due to their wildlife significance (as a European site)(under the (Conservation (Natural Habitats, & c) Regulations 1994).

G.2.11 In some areas of the country these ‘permitted development’ rights are more controlled. This means that, certain works that are located in a Conservation Area, a National Park, an Area of Outstanding Natural Beauty, the Broads, a World Heritage Site, or if the property is a listed building may require planning permission.

G.2.12 In any event, the GPDO does not allow any development that creates a danger to users of the public highway (Article 3 (6) refers), or development that is deemed to be ‘EIA development’ as defined by the Town and Country Planning (Environmental Impact Assessment) Regulations 1999. In these instances planning permission would be required.

G.2.13 Notwithstanding the permitted development allowances above, key considerations concerned with the exercise of permitted development rights would be to ensure compliance with other regulations or statute, and to obtain relevant licences etc. Some examples include the Wildlife and Countryside Act (1981) in relation to ecological/biodiversity, or the Ancient Monument and Archaeological Areas Act (1979) in relation to Scheduled Monuments, and the Conservation Areas and Listed Building Act (1990) in relation to those matters.

Site-Specific Considerations

G.2.14 On certain sites, it is important to note that the normal permitted development rights mentioned above would not apply. This will include sites where there is a specific prohibition of the specific works/use proposed, imposed by one or more of:

• A special development order.

• A Direction under Article 4 (‘Directions restricting permitted development’) of the Town and Country Planning (General Permitted Development) Order 1995 Order.

• A planning condition attached to a previous planning approval.

• An enforcement notice.

G.2.15 In areas in which permitted development rights have been removed or restricted, an application for planning permission would be required for the works.

Cost implications

G.2.16 Where planning permission is required normally a planning fee would be required for the LPA to process the application. The amount of fee will be determined by the nature of the development proposed and/or the site area in which development is proposed, as demarked on planning drawings by a red boundary line.


NANR201- The a:.sts ard Benefits of R2medialion J\2asures

The Planning Application process

G.2.17 Figure G.2 below illustrates the planning application process. In general planning applications should be determined by the local planning authority within 8 weeks (for minor applications), 13 weeks (for major applications), or 16 weeks where the proposal falls within the Environmental Impact Assessment (EIA) regulations. In cases where a planning appeal or re-negotiation of a scheme is required, this will add to the time taken to resolve the planning matters.

G.2.18 The planning authority should provide guidance as to what type of assessment and other information would be required in order for it to deal with the planning application.

G.2.19 Applications for planning permission shall be determined against a framework of planning policy that ranges from national guidance and instruction, through regional level policy considerations, to local development plans.

G.2.20 Proposed development should, unless overriding contradictory circumstances can be proven, accord with existing planning policy.


NANR201- The a:.sts ard Benefits of R2medialion J\2asures

Figure G 2 - PlanningApplication Process

(Source httpi/www.planningportal.gov.uklenglandlgenpublen/101OG7791930B.html )



National Planning Policy

G.2.21 The principal national policy guidance document for development associated with Noise is Planning Policy Guidance 24 (PPG24). PPG24 guides local authorities in England on the use of their planning powers to minimise the adverse impact of noise. The impact of noise can be a material consideration in the determination of planning applications.

G.2.22 PPG24 advises wherever practicable, new development involving noisy activities should be sited away from noise-sensitive land uses. Where it is not possible to achieve such a separation of land uses, local planning authorities should consider whether it is practicable to control or reduce noise levels, or to mitigate the impact of noise, through the use of conditions or planning obligations.

G.2.23 PPG24 details a number of measures that can be employed to control the source of, or limit exposure to, noise. Such measures should, it states, be proportionate and reasonable and may include engineering solutions such as the reduction of noise at point of generation (e.g. by using quiet machines and/or quiet methods of working); containment of noise generated (e.g. by insulating buildings which house machinery and/or providing purpose-built barriers around the site); and protection of surrounding noise-sensitive buildings (e.g. by improving sound insulation in these buildings and/or screening them by purpose-built barriers).

G.2.24 While measures to control or limit the exposure to noise may be required by PPG24, all other relevant planning policy must also be considered. For example, noise barriers, by virtue of their height, size, design and potential proximity to neighbouring residential properties, may be considered to be an inappropriate and visually intrusive form of development.

G.2.25 Other relevant issues identified within national guidance that may be applicable to the consideration of any noise control measure could include:

• The need to preserve the openness / undeveloped nature of Green belt.

• The need to protect the open countryside from unwarranted development.

• The need to protect the character and appearance of Conservation Areas, National Parks, Areas of Outstanding Natural Beauty, the Broads, and World Heritage Sites.

• The need to protect the character, appearance, and setting of Listed Buildings and consideration of archaeological sites (especially Scheduled Monuments).

• To have regard to the impact of climate change and flood risk issues.

Regional & Local Planning Policy

G.2.26 The planning policies contained within the various regional, sub-regional and local development plans vary across the UK. These polices should provide guidance as to what forms of development would normally be acceptable in certain locations. For this reason it is not possible to indicate through this document whether the various proposed noise control measures are likely to be acceptable and if planning consent would be granted.