DMRB VOLUME 8 SECTION 1 PART 2 - TA 84/06- CODE ... 8 TRAFFIC SIGNS AND LIGHTING SECTION 1 TRAFFIC SIGNALS AND CONTROL EQUIPMENT PART 2 TA 84/06 CODE OF PRACTICE FOR TRAFFIC CONTROL

CORRECTIONS WITHIN DESIGN MANUAL FOR ROADS AND BRIDGESFEBRUARY 2007

SUMMARY OF CORRECTION – TA 84/06 Volume 8, Section 1, Part 2CODE OF PRACTICE FOR TRAFFIC CONTROL AND INFORMATION SYSTEMSFOR ALL-PURPOSE ROADS

Corrections have been made to Chapter 8 – reference to ‘MCH 1869’ changed to ‘MCH 1969’.

We apologise for the inconvenience caused.

Highways AgencyFebruary 2007

London: The Stationery Office

May 2006

DESIGN MANUAL FOR ROADS AND BRIDGES

VOLUME 8 TRAFFIC SIGNS ANDLIGHTING

SECTION 1 TRAFFIC SIGNALS ANDCONTROL EQUIPMENT

PART 2

TA 84/06

CODE OF PRACTICE FOR TRAFFICCONTROL AND INFORMATIONSYSTEMS FOR ALL-PURPOSE ROADS

SUMMARY

This Advice Note is a primary reference documentdrawing attention to statutory requirements, relevantstandards and advice notes contained in existingdocumentation and provides general information ongood practice not fully covered in other documents.This document also offers guidance through definingnew practice and procedures associated with the safetyaspects of a scheme and by reflecting good practice andprinciples that have been established by UKpractitioners over the years. This document replacesTA 84/01 and MCH 1813.

INSTRUCTIONS FOR USE

1. Remove Contents pages from Volume 8 andinsert new Contents pages for Volume 8 datedMay 2006.

2. Remove TA 84/01 from Volume 8, Section 1which is superseded by this Standard and archiveas appropriate.

3. Insert TA 84/06 into Volume 8, Section 1.

4. Please archive this sheet as appropriate.

Note: A quarterly index with a full set of VolumeContents Pages is available separately from TheStationery Office Ltd.

TA 84/06

Code of Practice for TrafficControl and Information Systems

for All-Purpose Roads

Summary: This Advice Note is a primary reference document drawing attention tostatutory requirements, relevant standards and advice notes contained inexisting documentation and provides general information on good practice notfully covered in other documents. This document also offers guidance throughdefining new practice and procedures associated with the safety aspects of ascheme and by reflecting good practice and principles that have beenestablished by UK practitioners over the years. This document replacesTA 84/01 and MCH 1813.


THE HIGHWAYS AGENCY

TRANSPORT SCOTLAND

WELSH ASSEMBLY GOVERNMENTLLYWODRAETH CYNULLIAD CYMRU

THE DEPARTMENT FOR REGIONAL DEVELOPMENTNORTHERN IRELAND

Volume 8 Section 1Part 2 TA 84/06

February 2007

REGISTRATION OF AMENDMENTS

Amend Page No Signature & Date of Amend Page No Signature & Date ofNo incorporation of No incorporation of

amendments amendments

CorrectionNo 1 8/1 – 8/2 February 2007

Registration of Amendments


February 2007

REGISTRATION OF AMENDMENTS

Amend Page No Signature & Date of Amend Page No Signature & Date ofNo incorporation of No incorporation of

amendments amendments

Registration of Amendments

OVERVIEW

This Code of Practice has been produced to assisthighway and road authorities, consultants andcontractors who design and implement traffic controland information systems. This document is advisory,containing recommendations to assist in the promotionof safety and consistency of good design practice. TheCode covers conventional traffic signalling systems,signalled controlled crossings and innovative systemsincorporating driver information.

This Code of Practice includes a self-certificationprocedure under which highway authorities may certifythat they comply with the Code, refers to existingdepartmental legislation and advice and describesprocedures that have been established for many years. Itintroduces methodologies, which will be new to manyorganisations, such as the whole life cycle approach tosystems design.


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VOLUME 8 TRAFFIC SIGNS ANDLIGHTING

SECTION 1 TRAFFIC SIGNALS ANDCONTROL EQUIPMENT

PART 2

TA 84/06

CODE OF PRACTICE FOR TRAFFICCONTROL AND INFORMATIONSYSTEMS FOR ALL-PURPOSE ROADS

Contents

Chapter

1. Introduction

2. System Design

3. Manufacture and Supply

4. Installation, Testing and Commissioning

5. Operation and Maintenance

6. Decommissioning

7. Reference Documents

8. History

9. Enquiries

Appendix A Life Cycle Costing – Worked Example

Appendix B Glossary of Standard Terms

Appendix C System Certification Procedure


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Chapter 1Introduction

1. INTRODUCTION

1.1 General

1.1.1 Systems for controlling traffic or providinginformation to drivers are growing in complexity, andthe range of solutions available is getting wider. It isimportant that safety for the users of the road network isassured by good practice, during all phases of the lifecycle of these new intelligent transport systems. TheDepartment for Transport (the Department) alreadyprovides some aspects of good practice, together withlegislation and guidance. Other sources of advice areavailable both in the UK and Europe, but there was nosingle source covering the issues addressed in this Codeof Practice.

1.1.2 This Code of Practice recommends and makesreference to good practice to be adopted for all trafficcontrol or information systems, both simple andcomplex, and during all stages of the life cycle fromdesign and installation, through maintenance andoperation to eventual decommissioning of the system.

1.1.3 The document MCH 1969 ‘Traffic ControlSystem Design for All-Purpose Roads (Compendium ofExamples) (Ref. Section 7.2)’ is intended to assistdesigners of traffic control and information systems bypresenting examples that illustrate good practice.

1.1.4 The objective of this Code of Practice is topromote safety and effectiveness through good practiceand procedures, and to foster awareness when designingto give good value for money, of costs incurredthroughout the whole life cycle of the system. A furtherfunction is to form a central reference, guiding users toother relevant Department publications that containadvice on the design, maintenance and operation ofsystems.

1.1.5 This Code of Practice is aimed at a wide varietyof technical personnel engaged in the design andimplementation of systems, primarily:

• scheme designers in highway authorities andconsultancies;

• supervisors of installation and commissioning ofworks;

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• staff responsible for maintenance and operationof systems; and

• equipment manufacturers.

1.2 Scope

1.2.1 This Code of Practice applies to roadside systemsthat convey instructions or information to the road userthrough signal control, variable signs or symbols. Suchsystems will incorporate a control system, which will beelectrical, electronic or electro-mechanical. Purelymechanical systems are excluded.

1.2.2 This Code of Practice covers all-purpose publicroads operated by highways authorities (‘road’authorities in Scotland) except motorways in the UK.

1.2.3 This Code of Practice deals with systems whichthemselves form part of traffic schemes. In developing asafe design, a system cannot be considered in isolationbut must be viewed in its scheme context. This Code ofPractice is therefore concerned with detailed trafficengineering and control aspects of the system including:

• the layout, which provides the context for thecontrol or information system;

• the method of control; and

• maintenance.

1.2.4 While the aim of this Code of Practice is topursue safety and effectiveness throughout the wholelife cycle of the system, the recommendations it givesconcern activities undertaken during the design andimplementation stages only. These include theestablishment of a maintenance regime designed topreserve the safety of the system after commissioning.Safety is then controlled without further reference tothis Code of Practice, through procedures defined inmaintenance specifications and routines that thedesigner has ensured are appropriate for the continuedsafe operation of the system.

1.2.5 A proposal to modify the system should betreated in the same way as a new system, and hence thedesigners and manufacturers of the modification shouldfollow this Code of Practice.

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Concept Design(Section 2.7)

Preliminary Design(Section 2.8)

Detailed Design(Section 2.9)

Manufacture(Section 3)

Equipment Procurement(Section 3)

Installation(Section 4)

Site Acceptance Tests(Section 4.4.7)

Commissioning(Section 4.7)

Operation(Section 5)

Decommissioning(Section 6)

Minor ModificationsMaintenance(Section 5)

STAGE 1Safety Audit

(Section 2.5.3)

STAGE 2Safety Audit

(Section 2.5.3)

STAGE 3Safety Audit(Section 4.6)

System CertificationProcedure

(Section 2.3)

Statutory Approval(Section 3.7)

Does Scheme needStatutory Approved

Components ?Yes

No

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1.2.6 This Code of Practice also refers toconsiderations that may become important when thesystem is decommissioned.

1.3 System Certification

1.3.1 A formal process for certifying that procedurescontained in this Code of Practice, have been followedfor any particular system is System Certification. Theprocedure and forms are set out at Appendix C.

1.3.2 This Code of Practice has the status of an AdviceNote, and System Certification is not a statutoryrequirement for new systems. However, the completionof a System Certificate, such as the carrying out of aRoad Safety Audit, provides a discipline for schemedesigners. At the same time, it is a positive way ofdemonstrating that safety has been considered at allstages of the design and implementation process. Thiscould be needed if the safety of the system aftercommissioning is ever called into question.

1.3.3 Using this Code of Practice as a guide to goodpractice when preparing a system design does notnecessarily imply that the system must proceed to fullSystem Certification. Generally, any system that formspart of a traffic scheme, which undergoes a Road SafetyAudit, is a candidate for System Certification. However,it is for the organisation responsible for the system todecide whether System Certification is appropriate ornot. If it is decided that System Certification will bepursued, there are parts of the Code of Practice that areessential to certification which must be followed beforea certificate can be issued.

1.3.4 This Code of Practice therefore has two distinctapplications:

• It can be used as a general guide to good practice,in which case all its requirements are advisory.

• Alternatively, it can be used as a process forSystem Certification, in which case some of itsprocesses are mandatory in the sense that they arefundamental to the certification process.

1.3.5 The System Certification approach is the one thatshould be adopted for all-purpose trunk road schemes,unless otherwise directed by the OverseeingOrganisation. The requirements for SystemCertification are dealt with in more detail inAppendix C.

1.3.6 It is recommended that organisations formallyrecord their implementation method, for both this Code

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f Practice and System Certification. System designersan then use this methodology to help them follow therocess. It will also be helpful in demonstrating that therocess has been properly considered, if it is questionedr audited at a later date.

.4 Document Structure

his Code of Practice includes five further chaptersealing with scheme development:

Figure 1-1 Document Structure

System Design

(Chapter 2)

Manufacture andSupply

(Chapter 3)

Installation andCommissioning

(Chapter 4)

Operation andMaintenance(Chapter 5)

De-Commissioning(Chapter 6)

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• Chapter 2, Design, describes general andstatutory requirements for system designers andsystem design documentation. The principles ofsafety assessment and life cycle costing appliedto traffic control and information systems areconsidered, and procedures for design fromconcept through to detail are described.

• Chapter 3 describes good practice for themanufacture and supply of products used intraffic control and information systems.

• Chapter 4 concerns procedures for installation,testing and commissioning systems.

• Chapter 5 recommends good practice to beadopted in setting up and managing proceduresfor operation and maintenance with reference toexisting Department standards.

• Chapter 6 deals with the issues arising fromdecommissioning a system.

1.5 Implementation

1.5.1 This Advice Note should be used forthwith wheninstalling road schemes, including those currently beingprogressed, unless directed otherwise by the OverseeingOrganisation.

1.5.2 The use of this Code of Practice is stronglyrecommended for all traffic control and informationsystems and schemes on all-purpose trunk roads.

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Chapter 2System Design

2. SYSTEM DESIGN

2.1 Requirements for System Designers

2.1.1 Organisation

2.1.1.1 Although not an essential requirement, it isrecommended that design organisations should operatea Quality Assurance Scheme such as a schemeregistered with a UKAS accredited body under ISO9001 (Quality Assurance) or the European equivalentfor the design of traffic control and informationsystems.

2.1.1.2 When entering into a contract for the designof a traffic control system, the Client should ensure(through a carefully managed pre-selection process)that only competent organisations are invited to tender.

2.1.2 Qualifications

2.1.2.1 The design of traffic control systems is aspecialist activity. Although there is no specificqualification that ensures competence in this field,those involved in traffic control design should have anappropriate understanding of the engineering issues andexperience of traffic control work.

2.1.2.2 Although numerous documents (includingthis Code of Practice) are available which giveguidance on the design of systems, particularly thestandard ones, because traffic control systems havewide implications for safety and the environment, it isessential that a competent and experienced engineersupervises the design process.

2.1.2.3 In assessing the competence of staff ororganisation responsible for design, the following mayreasonably be considered:

• membership of a relevant professional body;

• familiarity with design of similar systems and thehealth and safety aspects concerned with them;

• the technical facilities and resources available tothe designer or design organisation.

2.1.2.4 Overseeing Organisations may wish todevelop a formal methodology for assessing thecompetency of design staff, to which evidence ofcompetency would refer.

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2.1.2.5 Evidence of competence of those responsiblefor the design of a system should be included in theDesign File. Design organisations can maintain lists ofcompetent staff that can be referred to in the DesignFile. Alternatively, the Design File can include a briefdescription of the individuals involved in the designprocess. This may be an appropriate method wheredesigns are carried out by external consultants.

2.2 Documentation

2.2.1 Design File

2.2.1.1 Each scheme or system should be developedusing a ‘Design File’ as a link between the individualstages of the whole life cycle. This file has someoverlap with the requirements of the Health and SafetyFile defined in the ‘Construction (Design andManagement) Regulations’ and the ‘Construction(Design and Management) NI Regulations’.

2.2.1.2 The purpose of the Design File is to providea record of the development of the system in its schemecontext, the decisions made and, in particular, the safetyconsiderations. It provides information tomanufacturers and installers and, followingcommissioning, becomes an historic reference file forthe project.

2.2.1.3 The Design File should include thefollowing information:

• Preliminary Design Brief (Section 2.7.3);

• Safety Case (including Risk Assessments)(Section 2.5.1);

• Output from safety review of Preliminary Designand Detailed Design including Stage 1, 2 and 3Road Safety Audits;

• Detailed Design Brief (Section 2.9);

• System Requirements Specification (Section2.9.3);

• Design change control documentation;

• System Certification;

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• Names, qualifications and experience of thedesigners identified as being involved in thedesign of the system;

• Test documentation;

• As-built drawings and specification; and

• As-installed configuration data.

2.2.1.4 Individuals or organisations charged withtasks at any stage in the system life cycle must ensurethat the Design File is available to them before work onthe task is permitted. As well as being important interms of ensuring that all design tasks are correctlycarried out, this approach will help ensure that abortivework is minimised.

2.2.1.5 Any changes to designs or specificationsshould be introduced in accordance with an agreedchange control procedure to ensure such changes arecommunicated to all others involved in the developmentof the system and its scheme context. The Design Filewill include details of design changes and how thesewere introduced.

2.2.1.6 The Design File should be retained to assistin the operation of the system, and to allow for thedesign process to be traced retrospectively, should asafety problem develop. Design material deemedrelevant to the system as installed and commissionedshould be held while the system remains in service, andfor a minimum of six years from the date when thesystem is superseded.

2.2.1.7 There is no prescribed form that the DesignFile must take but there must be some physical entitythat is identifiable as the Design File. As a minimum, itcould be a list of documents with a reference to whereeach one is stored. It is not sufficient that all thedocuments required to make up the Design File arecontained within a larger Project File unless the DesignFile components are specifically listed as such. It mustbe remembered that the Design File may be required forreference at any time during the life of a system and forsome time after. It therefore will stay in existence forlonger than many other archives. It must also beremembered that if the responsibility for a systemchanges, the Design File is to be passed to theorganisation taking over responsibility. If, forconvenience, documents are stored in different places,it must still be possible to construct a complete physicalDesign File at any time if required.

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2.2 Other Documentation Requirements

2.2.1 Other documentation includes thequirements of:

System Certification (Section 2.3);

Quality Assurance (Section 1.1);

System Requirements Specification (Section2.9.3);

The CDM Regulations (if they apply) (Section2.5.4);

Statutory Requirements (Section 4.2).

2.3 Statutory Regulations

2.3.1 All traffic control systems used on publicads must meet the requirements of any relevanttutory regulations. Those appropriate to schemes

volving traffic signals and signs (including pedestriannals) are contained in The Traffic Sign Regulationsd General Directions 2002, The Traffic Signsgulations (Northern Ireland), The Zebra, Pelican andffin Pedestrian Crossing Regulations and General

irections, The ‘Zebra’ Pedestrian Crossingsgulations (Northern Ireland) 1974 and The Traffic

gns (Welsh and English Language Provisions)gulations and General Directions 1985.

2.3.2 It should be noted that traffic signal displays,ad markings and variable message signs in legal termse considered ‘traffic signs’ and are subject to Theaffic Signs Regulations and General Directions 2002.

2.4 Statutory Approval

2.4.1 (See Section 3.7)

2.5 Signs Authorisation

2.5.1 Symbols and legends which form part of affic control or information system and which are notescribed within the regulations need specificthorisation by the Secretary of State, or in the case oforthern Ireland, the Department for Regionalevelopment; for Wales, The Welsh Assemblyovernment and for Scotland, Scottish Executive.

2.5.2 The sign authorisation procedure involvesthe submission to the Department for Transport (forEngland, or other appropriate body for Northern

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Ireland, Wales and Scotland) scale drawings of the signface and a plan showing the intended location. Both thesign face and the location form part of theauthorisation. Installation must be within the tolerancestated on the authorisation document. For signs, this isnormally within five metres of the authorised location.For signal installations, the tolerance is normally twometres.

2.3 System Certification

2.3.1 System Certification is a procedure, thedetails of which are set out in Appendix C, forrecording that the safety-related good practicerecommended by this Code of Practice has beenfollowed for any individual system. It is designed toensure that records of safety analysis and reviews areheld and can be audited, that the approval status isrecorded, and that the organisation and individualsresponsible for the different procedures are clearlydocumented.

2.3.2 Adopting the System Certification procedurewill also provide a record that demonstrates compliancewith the relevant Approving Authorities Approvalrequirements and aspects of the Health and Safety atWork etc. Act 1974 and the CDM Regulations.

2.3.3 The fundamental requirements of the processleading to System Certification are:

• procedures to ensure that safety aspects are fullyconsidered;

• the documentation and traceability of all safety-related decisions;

• the independent checking of all designs;

• accountability and competence.

2.3.4 In order to achieve these requirements, theessential elements of this Code of Practice are:

• setting up and maintaining a Design File;

• carrying out Risk Assessments;

• developing a Safety Case;

• undertaking an independent system review;

• recording names and competence of personnel.

2.3.5 The System Certification procedure runs inparallel with this Code of Practice, and consequently

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y apply to any system that falls within the scope ofs Code of Practice. The procedure starts at theliminary design stage, and is completed at the timecommissioning of the system. For significantdifications, the procedure is restarted and operates in same way as for a new system.

.6 The procedure requires designers,nufacturers and installers of systems to retaincific items of documentation, and to record specifiedormation, but does not attempt to standardise themat for the records, leaving this matter to thecretion of the organisations involved. Forms, which items of documentation, information and stages in development of the project, support the Systemrtification itself. Against each item, the informationessary to locate and audit the documentation has toentered.

.7 It is not an essential requirement for Systemrtification that design organisations operate aistered QA system, although it is a strongommendation. Where a formal ISO 9000 Qualitysurance system is in operation, it is recommendedt the System Certification procedure should beegrated within the QA procedures of designers,nufacturers and installers and subject to their ownernal and external Quality Assurance audits.

Quality Assurance

.1 The production of Quality Plans, archiving,ality and technical records, and the role of the Projectnager are requirements for all projects. The Qualityn may simplify the standard procedures for smallerffic control schemes.

.2 Designers of traffic control systems shouldly the requirements of HD 46, Quality Management

stems for Highway Design (DMRB 5.2.1), as manythe principles employed are similar to those forhway design.

Safety Assessment and CDM

.1 Safety Case

.1.1 The Safety Case is a logical argumentported by evidence to prove that the system in

estion has been developed to an acceptable level ofety. It describes the system and its boundaries, andntifies the hazards and risks indicating anyeguards provided. The Safety Case is concerned withth the system and the context in which it operates and

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relates to the system throughout its life cycle. The basisof the Safety Case for a traffic control or informationsystem should be a Risk Assessment prepared by thesystem designers.

2.5.1.2 In addition to the hazard list resulting fromthe Risk Assessment, the Safety Case should record:

• details of risk reduction measures employed;

• a description of the safety-related aspects of thecontrol systems;

• evidence of the competence of personnel engagedin the design of the system.

2.5.2 Risk Assessments

2.5.2.1 The designer should prepare RiskAssessments for all aspects of the system and itsphysical and human context throughout the completelife cycle, from construction, installation and testing tooperation, maintenance and eventual decommissioning.These Risk Assessments cover different aspects fromthose required under the CDM Regulations, which areprimarily concerned with risks associated with, orbrought about by, the physical construction of the site.

2.5.2.2 The preparation of Risk Assessments forcommon systems may be simplified by using checkliststhat identify the usual hazards, and measures toovercome them. When considering hazards in relationto construction or installation, liaison with thecontractor may reveal information that could be helpfulto designers.

2.5.2.3 The procedures for preparing a RiskAssessment start with drawing up a hazard list for thesystem in its scheme context. This is a list of elementsor characteristics of the system that present particularrisks. Hazards that are common to traffic controlsystems and which are already addressed by standardsand specifications need not be included. For example,display of conflicting green indications, which is apotential hazard at all traffic signals, is already dealtwith by the controller specification.

2.5.2.4 The hazard list should start with thosehazards which are inherent to the site such as visibility,steep approaches, overhead or underground highvoltage cables, the presence of vulnerable road userssuch as children, and disabled persons. It should go onto deal with potential hazards of the system itself,location and use of equipment and deal with anyspecific hazards of maintenance (such as servicing

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erhead equipment) and consequences of partial ortal equipment failure.

5.2.5 Innovatory aspects of systems warrantecial attention as they may present new risks thatuld require special counter measures. A feature ofch systems is that they are likely to require specialplications for specific approval from the relevantpproving Authority. It may be necessary to enlist thelp of additional expertise to assess the risks involvedd design the system to minimise their impact.

5.2.6 For each identified hazard, a note should beded detailing how the hazard is dealt with toinimise the associated risk and ensure that it isduced to an acceptable level. What represents ancceptable level’ of risk is largely subjective, but, as aide, if the totality of risk associated with a system isgher than the ‘do nothing’ alternative, this is clearlyacceptable even though there may be other benefits,ch as time savings, associated with it. Alternatively, avel of risk which is no more than is commonlyperienced in similar highway environments can begued as being ‘acceptable’.

5.2.7 It should be noted that hazards which have ary serious outcome but with a low level of risk ofcurrence are generally less acceptable than hazardsith a less severe outcome and a higher risk ofcurrence even where the total risk (computed as

kely outcome multiplied by the likelihood ofcurrence) is the same.

5.2.8 The development of a Safety Case and therrying out of Risk Assessments is an essential part ofe System Certification procedure. For simpler, lessmplex schemes there may be few unusual hazards butbrief Safety Case should nevertheless be prepared tomonstrate that the hazards have been fullynsidered.

5.3 Road Safety Audits and reviews

5.3.1 The Road Safety Audit procedure is andependent review of a system design to ensure that allfety-related issues have been fully addressed and theplications considered throughout the design andplementation of the system.

5.3.2 The staff involved in a Road Safety Auditould be independent of the staff involved in thesign. The Road Safety Audit team can be from anternal organisation or made up from staff of thesign organisation provided there are sufficient

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competent staff independent of those involved in thedesign available to carry out the audit.

2.5.3.3 The Road Safety Audit procedure may becarried out as it would for any traffic engineeringscheme provided the safety of the control andinformation system is reviewed either as part of anextended Road Safety Audit, or separately. The RoadSafety Audit and the review of the control andinformation system make up the Safety Review(Section 2.9.5).

2.5.3.4 The Road Safety Audit is carried out in fourstages:

• Stage 1: completion of preliminary design(before publication of draft orders);

• Stage 2: completion of detailed design (beforecommitment to the procurement process, e.g.invitation to tender);

• Stage 3: completion of construction (beforeopening);

• Stage 4: monitoring.

Stages 1 - 3 are relevant to this Code of Practice.

2.5.3.5 Where the scheme is of such a scale that nopreliminary design is carried out, a combined Stage 1/2Audit may be carried out (see HD 19).

2.5.3.6 When the review of the control andinformation system is incorporated in the Road SafetyAudit rather than as a separate process, the audit teamshould include one or two people with experience oftraffic control as well as road safety, or should appointan appropriate Specialist Advisor (see HD 19).However, it should be realised that the Road SafetyAudit process deals only with road safety. Issues ofsystem security and safety will need to be dealt withseparately.

2.5.3.7 Procedures for carrying out Road SafetyAudits on Highway Schemes (the principles of whichare equally applicable to traffic control schemes) are setout in HD 19 (DMRB 5.2.2).

2.5.4 Construction (Design and Management)Regulations

2.5.4.1 All construction projects are subject to therequirements of the CDM regulations with regard to thegeneral duty of care for those responsible for design

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nd construction. Projects which involve constructionork lasting longer than 30 days or involving more than

our people working on site at the same time have morepecific requirements under the Regulations, includinghe appointment of a Planning Supervisor and thereparation of a Health and Safety Plan and a Healthnd Safety File. Many of the more complex trafficontrol systems will fall into this category. It isecessary to identify very early in the design processhether the specific CDM regulations will apply.

.5.4.2 The purpose of the CDM regulations is tomprove the overall management and coordination ofealth, safety and welfare throughout all stages of aonstruction project, from the construction phasehrough maintenance to the final decommissioning.

.5.4.3 The regulations place duties on all those whoan contribute to the health and safety of a constructionroject. Duties are placed upon clients, designers andontractors, and the regulations create a new dutyolder – the Planning Supervisor. They also introducewo new documents – the Health and Safety Plan andhe Health and Safety File.

.5.4.4 The Planning Supervisor has theesponsibility of co-ordinating the health and safetyspects of project design and planning and ensuring thathe requirements of the Regulations are complied with,nd that the health and safety plan and the health andafety file are prepared.

.5.4.5 The Health and Safety Plan details all theealth and safety-related issues regarding theonstruction of the project. Hazards and risks are notednd working methods to ensure safe constructiondentified. The Health and Safety Plan is first developedy the Planning Supervisor before the tender stage andhen developed by the Contractor to take account of theork as carried out. It will identify significant hazardsr work sequences that cannot be avoided or designedut and, where appropriate, a broad indication of therecautions assumed for dealing with them.

.5.4.6 The Health and Safety File is a file which isanded over to the client following the constructionhase and which will assist persons maintaining,odifying or decommissioning the equipment in future.here is no prescribed format for the file but it will

nclude as-built drawings, design details, maintenancerocedures and any manuals provided by suppliers.

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2.5.5 Health and Safety at Work etc. Act

2.5.5.1 The Management of Health and Safety atWork Regulations also apply. These regulations makemore explicit what is required by the Health and Safetyat Work Act of employers. There is a requirement onemployers to assess the risks to health and safety oftheir employees and other who may be affected by thework activity. In the context of a traffic control system,this would apply to maintenance procedures and therisks to health and safety which they bring to employeesand members of the public. If a Health and Safety file isrequired for the project, any specific maintenanceprocedures that arise from the analysis of this RiskAssessment should be included in it.

2.6 Life Cycle Costing

2.6.1 Introduction

2.6.1.1 In examining the cost of a project, it isimportant that the total costs of the system over itslifetime are taken into consideration and not just theinitial capital cost. The on-going costs of a traffic signalinstallation are very different from those of aroundabout that may represent an alternative solution.Life Cycle Costing is also necessary to comparesystems involving different technologies where initialcosts and running costs may follow different patterns.

2.6.1.2 The basis of Life Cycle Costing is toaggregate the costs of a system over its lifetime into asingle sum. There are various methods of doing this butthe method recommended here uses the same basis ofanalysis as the computer cost benefit analysisprogramme, COBA described in the Department’sDesign Manual for Roads and Bridges, Volume 13:Economic Assessment of Road Schemes.

2.6.1.3 In the analysis, all costs are expressed atbase year prices. The base year can be the year thesystem is installed but this is not necessarily so. Anyother year can be used provided where two systems arecompared, the same base year is used in both. Where anannual cost (for example, maintenance) is expected toremain constant in real terms, the cost at base yearprices will be the same for each year, even though theactual sums expended may rise with inflation. It is nottherefore necessary to make any assumptions aboutfuture trends in inflation. If, however, it is expected thatcertain costs will rise in real terms (that is, will growfaster than the rate of overall inflation), the annual costsexpressed at base year prices will also grow.

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2.6.1.4 When the costs for each year of the life ofthe system (at base year prices) has been assessed, theycan be combined to produce a Net Present Cost bydiscounting future costs back to the present day, ormore accurately to the year in which the major initialexpenditure on the project is made. (Note, thediscounting is not back to the base year.) The principleof discounting is based on the fact that future costs areless onerous than present ones. At its simplest, on theassumption that it is possible to invest money at a rateof return higher than inflation, money invested now willgrow in real terms by an annual percentage equal to therate of interest received minus the rate of inflation.Consequently, the amount of money required now to beset aside to meet a future liability will be less than theliability itself.

2.6.1.5 The net interest rate used in the calculationis the Discount Rate. If a comparison is made between apresent cost and a future cost funded by moniesdeposited now in an interest bearing account, thediscount rate would be the difference between the rateof interest obtained and the rate of inflation, a net rateof about 2-3%. In practice, monies required later in aproject would not be deposited but be considered as areduction in current borrowing requirementsrepresenting a saving at the borrowing rate of interestthat is higher than the investment rate. Accordingly,higher Discount Rates are used in practice. TheDiscount Rate advised by the Department for use inCOBA is the appropriate one to use for life cyclecostings of traffic control systems.

2.6.2 Factors to be considered in Life CycleCosting

Life of Project

2.6.2.1 If the life of the project is known, or can bereasonably estimated, this should be used in theanalysis. This will be appropriate where, for example, atraffic signal system is to be installed when it is knownthat a planned future road scheme will require itsremoval. Where the life of the system is indeterminate,as is the case with the majority of traffic controlsystems, it is reasonable to equate the life of the systemwith the economic life of its major components. Atypical period which is consistent with data provided inthe specification for traffic signal controllers (TR2210/TR2500) would be fifteen years.

Initial Cost

2.6.2.2 An assessment of the initial cost willnormally be at hand at the time a life cycle costing is

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undertaken but it is important to ensure that allelements of the cost of implementing the system areincluded. In the case of a traffic signal installation thesewould include the costs of design, testing andcommissioning, the cost of connecting to the mainspower supply, and the cost of provision of acommunication line, outstation transmission ormonitoring unit, as well as the normal costs ofequipment and its installation, including civilconstruction. In deciding whether an item should beincluded in the initial cost it is necessary to ask whetherthe money and resources (including staff time)associated with that item would be saved if the projectwere not proceeded with.

Maintenance

2.6.2.3 Wherever possible, the costs of maintenanceused in the analysis should be based on actual costsincurred for the maintenance of similar systems in thearea. Where there is no better estimate, a good rule ofthumb is that the cost of maintenance of electronicequipment is approximately 10% of the initial cost ofthe equipment (excluding installation) per year.

Energy and Communications

2.6.2.4 An annual sum for the electrical supply tothe equipment and also for communications for controland monitoring should be estimated. The cost of energyand communications may well change in real termsover time and it is important to consider this,particularly where different technologies with differentcosts are being compared. A particular example iswhere newly installed cables are being compared withleased lines, dial-up or radio systems.

Insurance Repairs

2.6.2.5 Although it is not common practice for LocalAuthorities to insure street equipment, preferring totake the risk of accidental damage, the money expendedby an authority in repairing such damage is an overallcost which can be divided between individual systemsin much the same way as an insurance company dividesits risk between policy holders by charging an insurancepremium. Where possible, the likelihood of damage orloss to equipment should be estimated on the basis ofexperience and a value for the insurance calculatedfrom an estimated cost of repair for a typical claim,multiplied by the probability of damage occurring in agiven year. In areas prone to vandalism, an averagevalue of the cost of repairs due to this cause should beincluded. Alternatively, for traffic signals, a sumcalculated from the average annual expenditure per

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nstallation on maintenance not covered by theaintenance contract can be used.

taff Support

.6.2.6 Where major systems such as Urban Trafficontrol systems are undertaken, there are specific

taffing requirements for operation, which need to bencluded in the analysis. For more minor systems, theres still an increased staff support requirement. Alluthorities with significant numbers of traffic controlnstallations maintain a specialist staff team (or usexternal staff) and an increasing number of trafficontrol installations will naturally require an increase intaff resources. In calculating the costs of staff support,t is important to include overheads as well as salary.his will allow for the costs of increasedccommodation and administrative support staff.

.6.2.7 If a reasonable sum is allocated to this item,t can be taken to cover all redesign work during the lifef the project such as the recalculation of signalimings. If it is known that significant redesign will beecessary (because of other nearby systems proposed toe implemented during its lifetime) allowance can beade specifically through a cost assigned to a specific

uture year.

eplacements

.6.2.8 During the life of the system certain itemsay need replacing. It is important to check whether theaintenance estimates include all the replacement

equirements. In systems involving computers, it maye necessary to replace computer equipment before thexpiry of the economic life of the street equipment. Thee-cutting of detector loops is a common requirementor a variety of reasons and local experience should besed to assess what is the realistic average life ofetector loops and make an allowance for re-cutting. Ithould be borne in mind in making the calculation thatany instances of loop damage are due to Statutoryndertakers’ operations and the costs of repair can be

ecovered.

ecommissioning

.6.2.9 Where the life of the scheme is less than theconomic life of the equipment, there is some residualalue in the equipment. It is reasonable to calculate thatesidual value as a proportion of its initial cost based onhe proportion of its economic life still remainingrovided that a realistic estimate of the cost ofemoving, transporting, refurbishing and storing thequipment is also made. Clearly, if it is near the end of

2/7



its economic life, recovery of the equipment may not beworthwhile. Where there is no intention of removingthe scheme at the end of the economic life of theequipment, an assessment of residual value anddecommissioning costs can be omitted. Omittingresidual value is consistent with analysis of roadschemes using the programme COBA where theresidual value of roads at the end of the COBA analysisperiod is ignored.

When considering decommissioning costs, theconsequences of any current, or proposed, national orEuropean legislation on the disposal of waste materialsshould be taken into account.

2.6.3 Method

2.6.3.1 The data should be prepared in a table withone row for each year of the analysis. A spreadsheet is aconvenient tool for these calculations. Each row shouldshow the year and the costs associated with the variousheadings, a total cost for the year and the value of thatcost discounted back to the present year. The total ofthe discounted cost column gives the Net Present Cost.

2.6.4 Sensitivity Testing

2.6.4.1 Where a comparison between schemes isbeing made and future trends in costings are uncertain,possible ranges should be identified for the uncertaincosts and the Net Present Cost calculated for each endof the range to see if this affects the ranking of theschemes. If the ranking is changed by the sensitivitytest, judgement will have to be made about the mostprobable future cost pattern.

2.6.5 Worked Example

2.6.5.1 A worked example of a Life Cycle costingexercise is given in Appendix A.

2.7 Concept Design

2.7.1 Introduction

2.7.1.1 The assumed design process starts asconcept design, and proceeds through preliminarydesign to detailed design. The tasks of design willnormally be allocated to an individual designer or ateam of designers who may change as the designprogresses. This three-stage design process may beessential for some systems where a range of solutions

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ay exist. In practice all three stages may not becessary. It is not a requirement of Systemrtification that all the stages are separated provided

at all design-related decisions are fully documented.

7.1.2 ‘Concept design’ refers to the first stages ine life of a scheme when a problem, which could besolved by a traffic control or information solution, isst identified. The concept could result from an area-ide study or a specific investigation into a problemading to a range of solutions, not all of which areithin the scope of this Code of Practice. Design work develop a concept into a scheme is thenmmissioned by the Client.

7.1.3 This Code of Practice comes into effect oncetraffic control or traffic information system is putrward as a possible solution, and design resources arelocated to the task of preliminary design. The firstsk of the scheme designer is to establish a definitionr the scheme concept containing:

a description of the problem, preferablyquantified;

the scheme objectives; and

an outline of one or more solutions.

7.1.4 It is possible that the scheme concept willready be completely defined in a design brief. If not,is the designer’s responsibility to complete thefinition by agreement with the Client. It is likely thatis task will be a requirement of the designganisation’s quality assurance procedures.

7.1.5 Having defined the scheme concept, it may possible to assess some of the solutions withoutrther design work, allowing the selection of a more

ited range of solutions for further investigation.

7.2 Safety

7.2.1 Consideration should then be given to anynificant impact on safety that is apparent from theown details for each proposal by conducting aeliminary Risk Assessment for the whole life cycle ofe schemes from installation through tocommissioning. A brief written record should beade to be incorporated into the preliminary designief. The following issues should be addressed:

significant details of the safety history of the site;

the impact on safety of the proposed solutions;

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• the impact on safety of taking no action;

• the conditions of the work site; and

• any specific safety-related objectives of theschemes.

Figure 2-1 Concept Design

2.7.3 Preliminary Design Brief

2.7.3.1 A brief for the preliminary design stageshould be compiled containing:

• scheme objectives;

• alternatives to be considered, which will nearlyalways include taking no action;

• criteria for selection; and

• record of preliminary Risk Assessment.

Define System

Concept

Preliminary RiskAssessment

Prepare DesignBrief (Preliminary)

PreliminaryDesign Stage

Design Brief

Design File

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2.7.3.2 If possible, the brief should include thegeneral method of control and a list of the facilities tobe provided for each alternative. Any anticipatedrequirement for equipment approvals or special signsauthorisation should be noted, so that allowance can bemade within the design programme. If the schemeconcept is sufficiently advanced, it may be possible toconsider any requirement for the following:

• traffic regulation orders to restrict trafficmovements or parking;

• traffic surveys;

• topographical surveys; and

• public consultation.

2.7.4 The brief may also refer to any designpolicies set by the client or the design organisation anda project programme and budget.

2.8 Preliminary Design

2.8.1 Introduction

2.8.1.1 Preliminary design takes a scheme conceptand develops it in accordance with the preliminarydesign brief usually by evaluating one or more solutionsand producing a layout showing the main principles ofthe preferred option together with an outline of themethod of control.

2.8.2 Surveys

2.8.2.1 A pre-requisite of the design of a trafficcontrol or traffic information system is the availabilityof adequate traffic data and topographical information.Traffic data may be needed not only for design but alsoto predict and later monitor the benefit of the proposedscheme.

2.8.2.2 Where the objectives of the scheme are toovercome a defined traffic problem, any description ofthe existing conditions provided through traffic surveydata should be backed up by site visits by the designerto obtain first-hand experience

2.8.2.3 For schemes that entail no significantalteration to road kerb lines, base ordnance survey datamay provide sufficient topographical information, butcare should be exercised to ensure that the details areboth current and accurate. Limited surveys to checkcertain critical dimensions may be all that is required.

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For more significant changes in layout, a full threedimensional model of the existing physical topographymay be required. For major changes, early consultationwith statutory undertakers who may be affected, isrecommended. These consultations may lead torequirement to commission trial excavations toprecisely locate existing plant in relation to revised kerbalignments.

Figure 2-2 Preliminary Design Stage

Exceptions Report

Definition andAssessment of

options

Designer RiskAssessments

Preferred designoption

Stage 2 SafetyAudit / Review

Design File

Design Brief

Safety Case

Layout & Specs

Safety AuditReport

Detailed DesignStage

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2.8.3 Definition and Assessment of Options

2.8.3.1 Evaluation of the scheme objectives,alternative design solutions and design constraints willlead to a short list of options and sub-options fromwhich a preferred scheme is to be selected. The designof each option needs to be developed in sufficient detailto allow a budgetary estimate to be prepared, and aprediction of the scheme performance to be made. Thisnormally entails providing a layout at a scale of 1:1250or larger, together with details of the method ofoperation. Assessment of alternatives should considerthe same factors that are associated with the evaluationof any highway scheme, including:

• safety;

• scheme life cycle costs;

• environmental impact; and

• user and non-user benefits.

2.8.3.2 The evaluation of safety will require afurther preliminary Risk Assessment as conducted forthe scheme concept, but utilising the additional detailprovided through preliminary design.

2.8.3.3 The methodology used to evaluate thescheme benefits will be influenced by the objectives.Techniques for predicting the delays to road traffic attraffic signals are well developed and supported by arange of computer software. Software packages includeOSCADY and LINSIG for the analysis of individualsignal controlled junctions while TRANSYT can modelthe delays of a group or network of signals. Othermeasures of performance, particularly those associatedwith traffic information systems, are less easy topredict.

2.8.3.4 For the selected scheme it is necessary todemonstrate that there is a net benefit that exceeds the‘do nothing’ option. This usually entails a cost benefitanalysis which compares the value of benefits producedover the life of the scheme with the life cycle costs,discounted back to the year of installation as discussedin 2.7.

2.8.4 Safety Case

2.8.4.1 A Safety Case should be generated beforethe scheme develops beyond the Preliminary Designstage, otherwise a proposal may be developed forwhich, no viable safety case can be maintained. It

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should be based on a Risk Assessment of thePreliminary Design documented in a hazard list.

2.8.4.2 The designers should review The SafetyCase documentation at the Detailed Design stage. Thehazard list should be reviewed as the design changes oris developed in more detail, and the Safety Case shouldbe extended to cover any detailed safety requirementsdeveloped as part of the System RequirementsSpecification.

2.8.5 Safety Review

2.8.5.1 After a preliminary design has beencompleted, a safety review should be carried outindependently of the design team. This review maycomprise the Stage 1 Road Safety Audit extended tocover the control and operational aspects of theproposed traffic control or information system, or astandard Road Safety Audit and a separate independentreview of the control aspects of the system for trafficcontrol or information being proposed.

2.8.5.2 A copy of the Safety Review report isincluded in the Design File.

2.8.5.3 The design team should consider the SafetyReview report, and where appropriate, introducechanges into the design. All issues raised by the auditrequire a documented response. Where they have notbeen accommodated by changes in the design, thereasoning of the design team should be documented inan exceptions report.

2.8.5.4 The Safety Review report with thedocumented responses, together with any exceptionsreport, should be incorporated in a revised Safety Casedocument.

2.8.6 Other Preliminary Design Tasks

2.8.6.1 Other tasks during preliminary design thatmay be required include:

• advertise Traffic Regulation Orders;

• organise public consultation;

• submit scheme details for equipment approval orspecial signs authorisation when required;

• consult with police and other groups; and

• check vehicle turning envelopes where kerb linesare changed.

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2.8.7 Design File

2.8.7.1 On completion of the preliminary design, thefollowing documents should be assembled to form aDesign File:

• preliminary design brief;

• Risk Assessment including hazard list;

• Road Safety Audit and Safety Review Reports;and

• Safety Case document.

2.8.7.2 When a preliminary design is passed to anew team for design in detail, it is necessary to ensurethat the Design File is made available to them. To thisdocumentation, it may be helpful to add details onspecific detailed design standards set by the client,report on any design issues examined duringpreliminary design and to highlight any requirementsfor equipment approvals or special signs authorisation.

2.9 Detailed Design

2.9.1 Introduction

2.9.1.1 Detailed design develops the preliminarydesign proposals and produces layout drawings forconstruction and a detailed specification of systemrequirements.

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Figure 2-3 Detailed Design Stage

2.9.2 Layout Drawings

2.9.2.1 One or more detailed scheme layoutdrawings are usually first prepared using a scale ofeither 1:500 or 1:200 depending on the quantity ofinformation to be incorporated in the drawing. Thefollowing details should be defined:

Exceptions Report

Prepare detailedlayouts and SRS*

Update DesignerRisk Assessments

Finalise designs

Stage 2 SafetyAudit / Review

Design File

Revised SafetyCase

Safety AuditReport

End of DesignStage

Design brief,preliminary layout

& specs

Detailed layouts &SRS*

* SRS SystemRequirementsSpecification

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• existing and revised kerb lines;

• type and location of traffic signals and signs;

• type and location of electrically operated barriersand bollards;

• vehicle and pedestrian detectors and pushbuttons;

• paving details for footways and carriageways;

• road markings, static signs and bollards;

• guard railing;

• location of housings for control equipment andcable jointing; ducting and chambers for cablesassociated with the traffic control or informationsystem; and

• location of trees or other features that wouldinterfere either with the visibility of signals orsigns, or the location of street furniture.

2.9.2.2 The layout drawings form the base for thepreparation of a full series of drawings required forconstruction of all aspects of the scheme which willinclude some or all of the following details:

• setting out and pavement construction details;

• drainage;

• cabling details;

• location of statutory undertaker’s plant;

• street lighting and associated ducts andchambers;

• location of poles and housings;

• landscaping details;

• temporary traffic management duringconstruction and installation;

• detailed requirements for electricity supply andtelecommunication services;

• lighting columns;

• bus stops and shelters; and

• existing Traffic Regulation Orders (includingparking restrictions).

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2.9.3 System Requirements Specification

2.9.3.1 The method of operation for the systemdefined during preliminary design should be developedinto a specification that conveys the designer’sintentions fully and unambiguously to the supplier ofthe system. This task may not involve much detail orcomplexity, as the scope and level of detail required bythe System Requirements Specification (SRS) will varyconsiderably.

2.9.3.2 For conventional systems based entirely onapproved equipment, the SRS may be a list or drawingof the equipment to be installed and a simpledescription of facilities to be provided. Anyprogrammable aspects of the equipment will need to bedefined. For traffic signal installations, the SRS isprovided by the controller specification.

2.9.3.3 For innovatory systems that utilise approvedequipment in unconventional ways, or which make useof non-approved equipment, greater detail will berequired. At the discretion of the Approval Authority forStatutory Approval, it may be a requirement ofequipment approval that the SRS is submitted to themfor review. An SRS for such systems will contain someor all the following items:

• functional description of the method ofoperation;

• fault detection and warning systems;

• operation of equipment under defined failureconditions;

• specification for interfaces with other equipment;

• a reliability/availability target to be observed;

• system acceptance testing procedures;

• housing of external equipment;

• accommodation of instation equipment;

• EMC requirements; and

• any special provision for maintenance.

2.9.3.4 When there are alternative types ofequipment or systems available to meet therequirements of certain aspects of the system (forexample vehicle detection), it may be necessary toexamine the relative merits of the alternatives. The

May 2006

costs of operating or maintaining alternative systemsthroughout the life of the system may differsignificantly, and therefore any comparison of costsshould consider the full life cycle of the system.

2.9.3.5 The designer of the system or the supplierwill be responsible for the electrical design of thesystem. The SRS should make it clear who isresponsible for the work. The relevant organisation willbe responsible for signing the design section of theElectrical Completion Certificate, as required byBS 7671.

2.9.4 Revise Safety Case

2.9.4.1 During detailed design, the hazard list shouldbe reviewed and amended as proposals are modifiedand the operation of the system is defined in detail. Thisreview should address all stages of the system lifecycle, including the systems aspects of the constructionphase.

2.9.4.2 If the system falls under the specificrequirements of the CDM Regulations, a RiskAssessment relating to the construction phase will havebeen carried out. This Risk Assessment forms part ofthe Health and Safety Plan, which is a requirement ofthe designer under the CDM regulations. The ‘Client’s’obligations under the regulations should also bereviewed at this stage in relation to the appointment of aPlanning Supervisor and the preparation of a Health andSafety File.

2.9.4.3 The review should refer to the detaileddesign drawings and the SRS. Any changes in the riskreduction measures or the safety-related aspects of thescheme since the preliminary design stage should berecorded, together with reasons for the changes. Anyspecial requirements for the preservation of safetyduring maintenance, operation and eventualdecommissioning of the system should also be added tothe safety case. Such considerations may lead to arequirement to adapt the normal procedures operated bythe organisation responsible for maintenance andoperation.

2.9.4.4 At this stage, the designer should check toensure that any necessary approvals and authorisationsfrom the Secretary of State have been applied for.

2.9.5 Safety Review

2.9.5.1 On completion of detailed design, the designdrawings and SRS should be subjected to review by an

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Dev

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En

independent team. The review parallels the reviewprocess carried out at Preliminary Design stage (Section2.9.5). The review should comprise the Stage 2 RoadSafety Audit with the scope extended to consider theoperation of the system as defined in the SRS or astandard Road Safety Audit with a separate independentreview of the control aspects. The audit team (or thecontrol aspects review team if separate) should includea specialist in the specification of the equipmentinvolved. The review should consider not only thecontent of the SRS, but also any omissions.

2.9.5.2 For larger projects, it may be sensible toarrange an interim Safety Review to ensure that anycontentious issues, which could, for example, affectTROs, are considered early enough to be acted upon.

2.9.5.3 The design team as described in Section2.9.5 should consider the Safety Review report, and theSafety Case updated.

2.9.6 Other Detailed Design Tasks

2.9.6.1 Other detailed design tasks that may berequired include:

• preparation of detailed estimates of costs forsupply, installation and system maintenance;

• preparation of standard details and tenderdocuments;

• detail design, including foundations and crashprotection and the necessary approvals for mastarms and poles carrying heads above themaximum height prescribed in TSRGD, gantriesand other structures;

• preparation of the Health and Safety Plan; and

• determination of system maintenancerequirements, and the preparation of aspecification for system maintenance procedures.

2.10 Combined Preliminary and DetailedDesign

2.10.1 There may be situations where there is aneed to combine the preliminary and detailed designprocesses. This will follow the flow diagram as shown:

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Exceptions Report

elop Design

signer Risksessments

are detaileduts and SRS*

ge 2 Safetydit / Review

Design File

Safety Case

Safety AuditReport

d of DesignStage

Layout & Specs

* SRS SystemRequirementsSpecification

Design Brief

Figure 2-4 Combined Preliminary andDetailed Design

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Chapter 3Manufacture and Supply

PPLY
3. MANUFACTURE AND SU
3.1 Introduction

3.1.1 This Chapter describes good practice toensure safety and fitness for purpose to be adopted bymanufacturers and suppliers, where manufacture can betaken to include:

• preliminary and detailed design of equipment andsoftware;

• production of equipment and software;

• assembly of equipment and software to formproducts;

• configuration of products to specific purchaserrequirements;

• interconnection of products to form trafficcontrol or information systems; and

• testing of equipment and systems.

3.1.2 Manufacture also includes the assembly ofequipment or software supplied by others. Factorytesting and site testing of products configured to apurchaser’s requirements are considered in this Code ofPractice to be part of commissioning and installation,covered in Chapter 4.

3.1.3 The content of this Chapter is not onlyrelevant to manufacturers or suppliers, but also todesigners and operators who need to understand howsafety is assured in the systems they design and operate,and who may occasionally need to influence thisprocess.

3.1.4 In most traffic control and informationsystems, equipment with current statutory approvals isutilised in a standard configuration. Items of equipmentare developed, tested and manufactured to nationalspecifications appropriate to equipment of the samestandard type, and tested in accordance with statutoryapproval procedures. This process takes place prior topurchase, outside the life cycle of any particular trafficcontrol or information system, and results in typeapproved products that can later be configured tospecific applications.

3.1.5 Subsequent customisation of the equipmenttakes place after purchase, and consists of the

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introduction of data, and the configuration andinterconnection of hardware to form a complete system.This customisation process is considered in Chapter 4.

3.1.6 Some systems involve the development ofnew equipment for which there is no current statutoryapproval, or the use of approved equipment in non-standard configurations. In this situation themanufacturing process is part of the system life cycle,and the purchaser’s specification supplements anynational type specification that may exist. Theprocedures recommended for manufacture are the sameregardless of whether they are applied to equipmentdeveloped to a national type specification or apurchaser’s system requirements specification.

3.2 Requirements for Design Authorities

3.2.1 The Department’s Statutory Approvalprocedures require that suppliers who design andmanufacture equipment or who carry out modificationshave an appropriate quality management system. It isrecommended that this system is certified under ISO9000 by a certification body accredited by the UKAccreditation Service (UKAS) or a Europeanequivalent. The scope of the certification should berelevant to the product being submitted for approval.

3.2.2 It is recommended that purchasers shouldconsider the scope of this requirement to the purchaseof any items for which statutory approval is not arequirement.

3.2.3 The supplier’s quality procedures shouldinclude the activities required by this Code of Practice.

3.2.4 Design authorities should take due accountof current and imminent legislation with regard todecommissioning and disposal of redundant equipment.

3.3 Staff Competence and Training

3.3.1 Both management and staff have theresponsibility of ensuring that all personnel engaged inproduct development and manufacture, includingsuppliers and sub-contractors, are competent to performthe tasks assigned to them. Competence requires:

3/1



• having theoretical knowledge and practicalexperience appropriate to their role;

• awareness of current practice and availabletechnologies;

• familiarity with legislation, regulations andstandards; and

• awareness of relevant codes of practice forengineers and managers, e.g. the Institute ofElectrical Engineers Safety Related Systems.

3.3.2 Managers should ensure that project teamshave the appropriate balance of expertise to undertakethe project, covering the full range of disciplinesinvolved. To maintain this balance, they should ensurethat opportunities exist for trainees to acquireexperience from mature members of the team, and astructured training programme should be provided.

3.4 Product Development Life Cycle

3.4.1 The development process for productsintended for traffic control and information systemsshould be structured in a development life cycle thatembodies the safety life cycle specified in BS EN61508 Functional Safety of Electrical/Electronic/Programmable Electronic Safety-related Systems.Methods for product development within the life cycleframework should be defined within Companyprocedures. These methods should take into account therequirements of the statutory approval procedure.

3.4.2 The development process starts from anational specification or a purchaser’s requirementsspecification. These specifications should be reviewedto ensure that their requirements are clear, unambiguousand can be tested. A hazard and risk analysis of thepreliminary product design should be carried out, theproduct’s system safety requirements clearly stated andthose elements of the system that are safety-relatedshould be identified. (An example of a safety-relatedsystem is the green conflict monitor in a traffic signalcontroller.)

3/2

Figure 3-1 Product Development Life Cycle

3.4.3 The required extent of assurance that safety-related systems are safe should be determined withreference to relevant current standards such asBS EN 61508. For software, the assurance requirementcan set appropriate targets for availability, reliabilityand maintainability in product sub-systems where theseparameters can be predicted; using appropriatehardware and software design techniques to control theprobability of faults and failures; setting standards fortesting and the coverage of tests; using appropriate

Analyse Specification (Type or Purchase)

Hazard & Risk Analysis

Safety Related Systems Analysis &Standard Setting for Safety Assurance

Develop SystemRequirements *

Overall SystemValidation

* expanded in Figure 3.2

ValidationPlanning

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validation and verification techniques; and setting thedegree of independence required of the verificationprocess, with respect to the product design team.

Figure 3-2 Developing System Requirements

3.4.4 Validation of the design of safety-relatedsub-systems should include an analysis of probabilitiesand consequences of failure using techniques such asFailure Mode Effects Analysis.

3.4.5 A validation plan should be preparedcontaining tests or other validation procedures toestablish that the finished product meets the initialrequirements specification. The plan should take intoaccount any existing products, which may have beenpreviously validated and will not require further tests.The requirements of the statutory approval procedurefor environmental and EMC testing by an accreditedtest house should be accommodated within the plan.

3.4.6 The product system requirements shouldthen be developed starting by partitioning the systeminto modules using recognised methodologies. Thedesign may need to be developed iteratively insuccessively greater levels of detail until hardwareproduction drawings and circuit diagrams are produced.

3.4.7 Standards for the production of softwarecoding should be set within the company proceduresdefining best practice for all languages employed in theproduct software. Organisations involved in thedevelopment or supply of software should operate a

Module Design

Module Build

Integration

Verification

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Quality Management System capable of meeting therequirements of ISO 9001. The procedures shouldinclude measures to verify that the standards have beenobserved and that others can readily interpret thecoding.

3.4.8 When the national specification or thepurchaser’s specification requires that targets foravailability, reliability and maintainability (ARM) areto be modelled or predicted prior to production, then aplan detailing methods and sources of data to be usedfor prediction and subsequent monitoring should beprepared.

3.4.9 The product’s hardware and softwaremodules should be developed and verified through testsdesigned from a detailed knowledge of the productdesign and directed towards locating errors. Verificationtests should be carried out on modules when they areseparate and at various stages of integration.

3.4.10 The product prototype should be tested inaccordance with the validation plan to demonstrate theextent to which it meets the type specification or thepurchaser’s specification. Test procedures for theproduct development engineers should formulateproduction units for modules, sub assemblies andintegrated systems.

3.5 Legislation

3.5.1 It is important that designers are aware oftheir specific duties and obligations under currentlegislation. At the time of writing, legislation applicableto the industry includes:

• The Road Traffic Regulations Act 1984;

• The Traffic Signs Regulations and GeneralDirections 2002 (2002:3113);

• Traffic Signs Regulations (Northern Ireland)1997;

• The Zebra, Pelican and Puffin PedestrianCrossings Regulations and General Directions1997 (1997:2400);

• The Health and Safety at Work etc. Act 1974(1974 C37);

• The Health and Safety at Work Act (NorthernIreland) Order 1978;

• The Consumer Protection Act 1987 (1987 C43);

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• The Electricity at Work Regulations 1989 (SI1989/635);

• The Electricity at Work (Northern Ireland) Order1991;

• Building Regulations 1991 (SI 1991/2768amended by SI 1992/1180);

• Building Regulations (Northern Ireland) 1994;

• Other legislation published after the date of thisCode of Practice must also be complied with.

3.6 Legal Liability

3.6.1 Suppliers and Manufacturers should beaware of their liabilities for safety under current civiland criminal law. A summary of some of the legislationis provided in the following paragraphs.

3.6.2 Part 1 of The Consumer Protection Act(1987), which is the UK enactment of an EC directiveon Product Liability, makes compensation payable as ofright for injury resulting from the failure of a product tobe safe, without having to prove negligence.

3.6.3 Under part 2 of the same Act, it is a criminaloffence to supply ‘any goods ordinarily intended forprivate use or consumption’ which do not comply withthe safety requirement for reasonable safety havingregard to all the circumstances. The reference to privateuse or consumption makes this section of the act oflimited relevance to traffic control and informationsystems on public roads.

3.6.4 The Health and Safety at Work etc. Act(1974) places duties in criminal law on manufacturersand suppliers of articles for use in the workplaceconcerning the safety of the people who use them. Italso places responsibilities on manufacturers andsuppliers in respect of those people who have tomaintain their equipment.

3.6.5 The Sale of Goods Act (1979) definesimplied terms to a sale that include fitness for thepurpose required by the purchaser when this has beenexpressed. Most equipment within the scope of thisCode of Practice will also be subject to the terms of acontract under which they are supplied.

3.7 Statutory Approval

3.7.1 It is a statutory requirement that certain signsand signals (including associated control equipment) be

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approved by the Secretary of State before beingdeployed on UK public Highways. The HighwaysAgency, at the time of publication of this Code ofPractice, undertake UK Approval on behalf of theSecretary of State.

3.7.2 The procedure for obtaining StatutoryApproval is defined in the Highways Agency documentTRG 0600 – ‘Self-Certification Procedures forStatutory Approval of Traffic Control Equipment’.

3.7.3 It is the responsibility of Scheme designersto specify to the supplier that any equipment fallingunder the categories defined in TRG 0600 should be ofan approved type, while the Design Authority (often,but not always the manufacturer) for the equipment hasthe responsibility to obtain the Approval.

3.7.4 In supply contracts for equipment subject toStatutory Approval, the supplier should be required tosupply evidence of the approval status of the equipmentand a reference to that evidence should be included inthe Design File for all systems using that equipment.

3.7.5 When the Design Authority considers that ithas achieved full Conformity with the requirementsdefined in the appropriate Technical RequirementsSpecification, a Declaration of Conformity may then besubmitted.

3.7.6 This must only be submitted when theDesign Authority is satisfied that all the functionalrequirements have been satisfied, all the requiredtesting has been satisfactorily completed and endorsed,the Product is fit for purpose and the Design Authorityaccepts the full legal liability for the Product.

3.7.7 Once the Approval Authority is satisfied thatthe requirements of TRG 0600 have been met in respectof a Declaration of Conformity, a Letter of Acceptance,that grants Approval for the Product to be used on theUK public highways will be issued.

3.7.8 No Product is approved for such use unlessthe Design Authority is in receipt of such a Letter ofAcceptance specific to the Product and its uniqueproduct identifier.

3.8 European Directives and CE Marking

3.8.1 It is the supplier’s legal responsibility toensure that all products comply with all relevantEuropean directives. The decision as to whichdirectives are applicable rests with the supplier.

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Relevant directives may include:

• Low Voltage Directive;

• EMC Directive;

• Telecom Terminal Equipment Directive;

• Machinery Directive; and

• Safety Directive.

3.8.2 (The scope of the Safety Directive is limitedto the safety of system operators or maintainers.)

3.8.3 All new electrical equipment sold in Europehas to be CE marked to show that it complies with allthe relevant directives. For some classes of equipmentsuch as terminals to be connected to the publictelephone network, type approval by a notified body isrequired, and the equipment has to be examined by theapproval body.

3.8.4 For other products that are fully compliantwith the relevant specifications, the supplier can selfcertify CE compliance. The supplier’s proceduresshould identify individuals responsible for ensuring thatthe design meets the relevant requirements, and thoseauthorised to sign a declaration of conformity. Theprocedures should specify the checks required and theevidence that should be prepared before the product canbe certified.

3.8.5 When there is not full compliance with thespecifications referred to by the directives, informationabout the product must be submitted to be certified by acompetent body appointed by the relevant ApprovalAuthority. It is a legal requirement that this informationand other details associated with the certification areretained in a Technical Construction File.

3.8.6 Regardless of whether or not a TechnicalConstruction File is required, the supplier’s qualityprocedures should ensure that documentary evidence ofconformity to the EC specifications is retained and caneasily be located. The procedures should specify areasonable period for which the information is to beheld. The CE Marking Directive stipulates that certaindocumentation is retained for a minimum period of tenyears.

3.9 Project Management

3.9.1 Manufacturers and suppliers should adoptrecognised principles of good practice both in the

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management of product development and subsequentreplication of units, which should be enforced through aquality assurance system. Management proceduresshould cover both the commercial and engineeringaspects of the project.

3.9.2 Before the start of a development project, itis necessary to define the project with reference to theproject’s objectives, any purchaser requirements, typespecifications and legislative requirements. A projectplan should also be prepared and developedincorporating:

• a product development programme;

• a product development life cycle;

• a software development plan;

• verification and validation plans;

• review and assessment procedures; and

• change control procedures.

3.9.3 Configuration management proceduresshould be instigated to ensure that for any item ofdocumentation, software or hardware, its status(current/superseded, tested/untested, original/modifiedetc.) can be easily ascertained. The effectiveness ofsuch procedures should be monitored.

3.9.4 The safety and reliability performance ofproduction replicas of the development prototypeshould be controlled and validated throughmanufacturer’s Quality Assurance procedures.

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Chapter 4Installation, Testing and Commissioning

G AND COMMISSIONING
4. INSTALLATION, TESTIN
4.1 General

4.1.1 This Chapter covers the period of thescheme life cycle from after completion of detaileddesign to bringing the system into operation.Installation includes the implementation of both thecivil and electrical engineering aspects of the scheme.Pre-commissioning functional and electrical tests ofconfigured control equipment, signs, signals and cablesare carried out separately and with the system fullyassembled. Commissioning refers to the final processfor bringing the system into operation, checking itsfunctionality in traffic terms and handing it over intomaintenance.

4.1.2 Local Transport Note 1/98, The Installationof Traffic Signals and Associated Equipment,recommends good practice for the installation ofpermanent traffic signals and reference to this documentis made throughput this section. Much of the advicegiven is equally applicable to the installation of alltraffic control and information systems, as well as themore conventional signals within its scope. Thedocument covers all aspects of installation work.

4.1.3 Organisations involved in the installation ofequipment and cabling for traffic control systemsshould have an accredited registration for QualityAssurance to ISO9000 with specific reference to thetype of work involved. Specialist sub-contractorsengaged in slot cutting may be exempt from thisrequirement but must be adequately supervised by aQuality Assured organisation.

4.1.4 Staff employed in installation, testing andcommissioning should be trained and competent for thetasks assigned to them and conversant with the relevantrequirements of BS7671 Requirements for ElectricalInstallations (formerly the IEE Wiring Regulations) andthe Electricity at Work Regulations 1989.

4.1.5 Those involved in the supervision of thework and the acceptance of the completed system needto be fully conversant with the functions specified forthe equipment and the safety aspects both of thecompleted system and the installation andcommissioning process.

4.1.6 Consideration should be given to the impactand benefits on the life cycle of the system of the

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appropriate Sector Scheme managed by the SectorScheme Advisory Committee and promoted by theHighways Agency, Local Highway Authorities andIndustry.

4.1.7 The Sector Schemes relate to the qualitymanagement system requirements for the installationand maintenance of electrical apparatus and associatedstructural supports, cabling for highway lighting andtraffic signs and the installation and maintenance oftraffic control equipment and associated apparatus. Itsets out to identify a common interpretation of BS ENISO 9001: 2000 for Organisations and Certificationbodies engaged in the specific sectors of the nationalhighway electrical works to promote safe, consistentand competent working

4.1.8 As a measure of quality management andcompetency, it is recommended that, where appropriate,Sector Scheme are in existence, then they should bespecified in contracts. If specified in the contract, thenthe provisions of the appropriate sector scheme shall beimplemented during installation, testing commissioningand maintenance.

4.2 Statutory Requirements

4.2.1 Major schemes may fall within the specialrequirements of the CDM regulations whoserequirements are summarised in Chapter 2.

4.2.2 Before starting work, the principal contractoris required to produce method statements that describehow risks identified in the Health and Safety Plan are tobe overcome.

4.2.3 Other regulations and advice documents thatmay be relevant are listed below. A summary of theirmain requirements is given in LTN1/98.

• The Health and Safety at Work, etc. Act 1974;

• The Health and Safety at Work Order (NorthernIreland) 1978;

• Chapter 8 of the Traffic Signs Manual;

• Electricity at Work Regulations 1989;

• Electricity at Work Regulations (NI) 1991;

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• The Road Traffic Regulation Act 1984;

• The Road Traffic Regulations (NI) Order 1997;

• The Highways Act 1980;

• The Road (NI) Order 1993;

• The Road Traffic (NI) Order 1993;

• The Disabled Persons Act 1981;

• The Disabled Persons (NI) Order 1982;

• New Roads and Street Works Act 1991;

• Streetworks (NI) Order 1995;

• Avoiding Danger from Underground Services,HSE, 1991;

• BS7671 Requirements for ElectricalInstallations;

• Other legislation published after the date of thisCode of Practice must also be complied with.

4.2.4 The installation of the traffic control systemincludes both civil engineering and electrical aspects ofthe system, and will involve different specialistsworking on site possibly for different contractors orsubcontractors or as part of a team undertaking a rangeof disciplines associated with:

• ducting and road construction;

• traffic control equipment and cabling;

• road markings;

• street lighting;

• signs;

• telecommunication circuits; and

• electricity supplies.

4.2.5 Regardless of the contractual arrangementsunder which these specialists are engaged, this workneeds careful planning and co-ordination.

4.2.6 In particular, the traffic managementmeasures that ensure safe conditions for road usersduring the installation process need to be carefullymonitored. The cutting of detector loops which is arelatively quick operation but which requires the

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closing of whole traffic lanes is an aspect of installationwhere traffic management is important but prone to beomitted if not properly supervised. Authorities mayconsider specifying the employment of a specialisttraffic management contractor.

4.2.7 Installation supervisors will need to checkthat equipment is installed in the correct position andcorrectly aligned. Cabinet bases and signal poles shouldbe installed as in LTN 1/98 (Chapter 7). Controllersshould be aligned so that the doors open as intended.

4.2.8 Planning the installation of schemes thatinvolve the modification of existing traffic controlsystems should take into account any requirements tomaintain safe and adequate control facilities until themodified system is commissioned. Particular attentionshould be paid to the requirements of pedestrians andvulnerable road users.

4.2.9 For new systems, it is important to ensurethat new signs or signals, including road markings, donot give confusing indications to road users before thesystem is commissioned. To avoid problems, it isadvisable to schedule elements such as road marking tobe done shortly before the commissioning.

4.2.10 The installation process should ensure thatany warning signs connected with the system, such as‘new traffic signals ahead’ are erected, and, as withtraffic signal heads, are covered over untilcommissioning takes place.

4.2.11 Particular attention is drawn to the safetyimplications of installation work, the necessity ofmaintaining signing and barriers to the requirements ofChapter 8 of the Traffic Signs Manual to protect theworks, and the need to plan the installation works tominimise disruption and danger to road users.

4.3 Testing

4.3.1 Statutory approved equipment is testedduring development and manufacture to ensure that itcomplies with the relevant national equipmentspecifications which are not scheme specific, and thereis consequently no need to repeat such tests forindividual systems. The role of testing in the life cycleof a scheme is therefore to verify that the scheme-specific requirements have been implemented correctlyas follows:

• to verify that separate items of equipment havebeen configured in accordance with theconfiguration specification;

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• to verify the performance of the integratedsystem, including cabling, interfaces andcommunication circuits;

• to test electrical cabling and earthingarrangements in accordance with the relevantregulations;

• to verify that the equipment and cabling havebeen installed correctly through inspection; and

• to carry out specific tests of functions related tosafety.

4.3.2 For items not subject to Statutory Approval,the manufacturer’s tests will not have been subject tothe requirements of the Statutory Approval procedureand it may be necessary for purchasers to considerextending the scope of the testing.

4.3.3 The scope of the system may include notonly the local traffic control or information system, butmay also include a central monitoring or control systemand communications system from the centre to sitewhich will need to be subject to testing.

4.3.4 Tests may be carried out variously by thesuppliers, the installation contractors, designers or thoseresponsible for supervision. It is usually a requirementof supply and installation contracts that specified testsare witnessed on behalf of the purchaser during afactory acceptance test (FAT) or site acceptance test(SAT). The extent and scope of such tests will dependon the size and complexity of the traffic control orinformation system. For simple systems, the FAT maybe omitted.

Test to Verify Configuration

4.3.5 For microprocessor-based controlequipment, customisation to the specific requirementsof the scheme involves the input of configuration data.Testing is essentially a check that the data agrees withthe configuration specification and it provides therequired method of control. It is recommended that testsare conducted to a previously prepared schedule, buttime should be made available for unstructured testing.Particular attention during tests should be paid to inputdata consisting of logic or special software.

Tests of Completed System

4.3.6 When tests of the integrated system areperformed prior to installation, they will normallyinvolve the control system connected to some, but notnecessarily all, associated equipment. For complex

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systems, some items may be simulated by hardware orsoftware representations of their interface with thecontrol system, provided the representation can beshown to be accurate.

4.3.7 A complete integrated test is required for allsystems after equipment has been installed, prior tocommissioning.

Electrical Cable and Earthing Tests

4.3.8 LTN 1/98 (Chapter 12) lists the tests to beperformed and certified on the mains supply, cables andearthing. These tests are requirements of BS7671 andthe Specification for Highway Works clause 1217.

Inspection to Verify Correct Installation

4.3.9 An important part of testing is a visualinspection to ensure that the equipment is constructedand installed correctly. The visual inspection shouldinclude checking that cabinet door seals and locks areacceptable; cable properly labelled, terminated andbonded; mains supply fuses and cut-outs correctlyinstalled; telecommunications cable properlyterminated, and necessary warning labels attached.

Functional Safety Checks

4.3.10 Test and checking procedures should ensurethat all safety critical functions are verified. Whendesigning tests to be undertaken at the installation andcommissioning stage of the system life cycle, dueallowance should be made for the risks inherent in thetests themselves. Product tests previously undertaken bymanufacturers and suppliers may have already validatedthe safety critical functions more effectively than can beachieved on-site. For example, conflict monitor tests onpelican controllers may be unnecessary at installation ifthe supplier carries out adequate tests duringproduction.

Documentation Requirements

4.3.11 For simple systems, the specification may beused as a checklist of items to be tested. For morecomplex systems and systems using innovativetechniques, test schedules for both the Factory and SiteAcceptance Tests should be drawn up. It is common forthe Supplier’s contract to include the requirements todraw up test schedules for the purchaser’s approval.Whether the tests are based on formal test schedules ornot, the details of the tests, date, place, timerepresentatives present, functions tested, equipmentused and the results obtained should be fully recordedand the records kept in the Design File.

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4.3.12 The Contractor who is responsible for thetests should provide an electrical installationcompletion certificate in accordance with BS 7671.(Note: A competent person should sign thesecertificates on behalf of the Contractor.) There is also arequirement for the electrical installation designauthority to sign confirming their responsibility for theelectrical design of the system.

Safety and Signing

4.3.13 Precautions should be taken during sitetesting to assure safety for road users. Where testinginvolves obstruction of the carriageway or footway, it isa legal requirement that Chapter 8 of the Traffic SignsManual be followed. Any potentially misleading signsor indications should be covered. Where this is notpracticable, such as when large Variable Message Signsare being tested, steps should be taken to minimiseproblems (in this example by using test legends whichdo not mislead and by the use of advance “signs undertest” sign boards).

4.3.14 Precautions should also be taken during teststo protect employees from the risk of electrocution andother hazards. Where tests involve an element of risk, arisk analysis should be carried out to identify testmethods to minimise risk or to determine whether thetest should be carried out.

4.4 Publicity

4.4.1 Where the scheme in operation will require adifferent response from road users, or affect routechoice, it may be necessary to mount a publicityexercise before and after commissioning. For example,temporary signs can be uncovered at commissioning,and used to warn of changes and then left in place forseveral months.

4.4.2 News coverage through press releases,articles and contacts with radio and television can beuseful to warn the public of important changes to thenetwork or the commissioning of major traffic controlor information systems.

4.4.3 Official opening ceremonies, if called for,should be carefully planned in conjunction with thepolice, and occur only when the system iscommissioned ready to be switched on. If a benefit ofthe system is to be an improvement in safety, then it isinadvisable to delay bringing it into operation withoutgood reason.

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5 Road Safety Audit

5.1 After installation and before commissioning,stage 3 Road Safety Audit as described in HD 19ould be carried out to ensure that all the safetyplications of the physical and operational aspects of

e system have been fully considered.

6 Commissioning

6.1 The commissioning of the assembled systemllows confirmation that all tests and systemsrtification procedures have been completed. Details the procedure are set out in Appendix C.

6.2 Before commissioning takes place, thellowing formal documentation should be checked:

evidence of equipment approval status;

factory test completion documentation;

site test completion documentation; and

maintenance documentation required on site.

6.3 It is unlikely that final as-builtcumentation will be available at the time ofmmissioning but, as a minimum, accurate hand-ritten information should be made available foraintenance. Final documentation should be supplied soon as possible after commissioning. It iscommended that contracts for installation shouldipulate a reasonable time limit for the supply of suchcumentation.

6.4 Verification that all legal procedures, publicformation exercises and educational programmesve been completed before the scheme is brought intorvice will be required. It will be necessary to validatee proposals for the successful future operation andaintenance of the system throughout its life cycle byitably trained and qualified personnel in accordanceith fully documented procedures and the technicalformation, which will be made available to them.

6.5 Proper proposals for future modifications to,d the possible decommissioning of, the scheme in afe and efficient manner should be confirmed.

6.6 A final check that all certificates,ecifications and drawings are included in the ‘Design

ile’ should be made.

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4.6.7 The Design File should, as a minimum,include the following:

• final Design Drawings;

• design checklists;

• System Requirements Specification;

• Stage 1, 2 and 3 Road Safety Audit reports;

• details of operational procedures;

• details of maintenance procedures;

• details of modification and decommissioningprocedures;

• details of factory and site acceptance tests; and

• System Certification documentation.

4.6.8 The commissioning process brings the newscheme into operation by:

• uncovering signals and signs and switching themon;

• uncovering temporary warning signs;

• completing road markings that have to be omitteduntil commissioning;

• checking and acceptance of the system by themaintenance body; and

• mobilising publicity.

4.6.9 Commissioning also incorporates testing andmonitoring of the system under live conditions toconfirm the safe operation of the system.

4.6.10 At this stage, the Overseeing Organisation ora representative gives formal confirmation that thesystem has been completed in accordance with thecontract, and ownership of the system passes from theContractor to the Overseeing Organisation on signing ofa hand-over certificate.

4.7 Monitoring

4.7.1 There should be close monitoring of theoperation immediately following commissioning.

4paOunDtcf

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.7.2 A scheme that is properly designed andassed through a Road Safety Audit should not presentn additional risk to road users unfamiliar to the area.n the other hand, there is potential for problems forsers so familiar with the previous situation that they doot respond to the changes in layout or signing.epending on the level of this risk, it may be necessary

o monitor the system’s operation, possibly withontinuing police presence, for the hours or daysollowing commissioning.

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ENANCE

Chapter 5Operation and Maintenance

5. OPERATION AND MAINT

5.1.1 Introduction

5.1.1 Once a traffic control or information systemhas been commissioned it is important to ensure that itis operated and maintained in a way that the safety orfitness for purpose introduced during the design andinstallation process is not compromised during the laterstages of the life cycle. Systems are normally operatedand maintained by the Highway Authority responsiblefor the road network on which they are situated, buttasks are often distributed amongst several bodiesincluding contractors and departments employeddirectly by the Highway Authority.

5.1.2 Operation is taken to include:

• the monitoring and adjustment of systems andtheir environment;

• the monitoring of the effectiveness ofmaintenance; and

• tasks associated with manned traffic controlcentres.

5.1.3 Operation is usually undertaken by staffdirectly employed by the Highway Authority.

5.1.4 Maintenance consists of the tasks required toensure that the equipment and cabling continues tooperate in accordance with the specifications, andincludes routine inspections, replacement ofconsumable items, fault response and repair. Normally,specialist maintenance contractors are engaged to carryout this work.

5.1.5 A newly installed system is normally subjectto the standards and procedures for operation andmaintenance that are applied generally to traffic controland information systems by the responsible authority. Itis therefore the responsibility of the designer (asdiscussed in Chapter 2) to design a system that willremain safe under the existing arrangements operatedby others. Where a new system involves systemmaintainers or operators in new areas of expertise, anytraining requirements should be identified at the designstage.

5.1.6 This Chapter recommends good practice tobe adopted in the setting up and management ofprocedures for operation and maintenance making

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particular reference to Departmental standards found inTD 24. This document specifies minimum requirementsfor inspection and maintenance procedures on all-purpose trunk roads but can be taken as guidance forother public roads.

5.1.7 It is not the aim of this Code of Practice toset absolute standards for operation and maintenance.

5.2 Maintenance Organisations andPersonnel

5.2.1 It is a requirement of TD 24 that for systemson all-purpose trunk roads, maintenance contractorsshould be registered under ISO 9002 (QualityAssurance) with a UKAS accredited body for themaintenance of traffic control and communicationsystems. Specialist sub-contractors engaged in slotcutting, cleaning and lamp changing may be exemptfrom this requirement, but their activities should besupervised by an organisation registered under ISO9000. It is recommended that Highway Authoritiesshould consider adopting the same requirements for allclasses of roads.

5.2.2 It is important that all personnel involvedwith the maintenance of traffic control and informationsystems are suitably qualified and adequately trained onthe equipment to be maintained, and this requirement iscontained in TD 24. They should also be familiar withthe contents of the Electricity at Work Regulations.

5.2.3 As a measure of quality management andcompetency, it is recommended that all appropriateSector Schemes are specified in contracts.

5.2.4 Operators may be required to undertake:

• traffic monitoring and adjustment of the trafficcontrol system at the control centre;

• interpretation of fault data from equipmentmonitoring systems;

• routine management of faults and maintenancecontractors; and

• the on site inspection and adjustment of systems.

5.2.5 To carry out these roles effectively, operatorsneed appropriate knowledge of the systems they

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operate, and familiarity with the arrangements formaintenance and the terms of maintenance contracts.

5.2.6 Some systems allow for access to specifiedfunctions to be restricted through passwords topersonnel with appropriate expertise or authority.

5.2.7 Responsibility for identifying and fulfillingpersonal training needs of maintenance and operatorpersonnel rests both with the individual concerned andthe organisation. Particular care is required to ensurethat expertise keeps pace with the changing state of theart in the field of traffic control and informationequipment.

5.2.8 Formal training for the new and existingitem of equipment or systems should form part of theroutine of the organisations involved. It is thereforerecommended that such organisations should maintainand monitor a training plan for its employees containingtargets, time budgets and programmes. Wheremaintenance or operation is undertaken under contract,the formulation of an agreed plan should be arequirement of the specification and enforced throughappropriate penalties upon failure to comply.

5.3 Control Centres

5.3.1 When formulating arrangements for theoperation and maintenance of traffic control andinformation systems, consideration should be given toadopting a single fault control centre for reporting,collating and the clearance of faults. Such a centre willallow operators to set priorities when conflicts occur.Satellite control centres may be added, each with theirown link with fault monitoring and managementequipment. It is common practice for fault control andthe operation of urban traffic control systems to takeplace within the same control centre.

5.3.2 Computer-based fault management systemsassist the management of maintenance by providing adatabase for recording and tracking the progress ofcurrent faults and monitoring routine inspections. Thesesystems also maintain a fault history for eachinstallation, allowing analysis of the fault rates ofequipment types. Fault management systems can belinked to remote monitoring and urban traffic controlsystems for automatic logging of faults.

5.3.3 The hours of manning and number of staffrequired in control centres will depend on the size andscope of the control and monitoring systems,anticipated requirements for manual intervention, andthe presence of CCTV and radio communication

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systems. When assessing staffing needs it may beworthwhile consulting the system designers,manufacturers and other authorities with similarrequirements.

5.3.4 When considering the most effective way oforganising operator duties, managers need to rememberthe health and safety problems associated with extendedviewing of computer and television monitors.

5.3.5 Authorities responsible for urban trafficcontrol systems should enforce procedures governingthe actions taken by operators to maintain the safeoperation of traffic signals. Action plans for specificincidents may need to be developed in conjunction withother agencies such as the police.

5.3.6 Displays showing data derived from themonitoring of equipment or traffic can provide a usefulsystem overview. Displays based on large computermonitors or projection systems are more flexible andeasier to update than wall maps.

5.4 Remote Monitoring

5.4.1 Traffic control and information systems canhave some of their operational functions monitoredremotely by either Remote Monitoring or Urban TrafficControl Systems. Such monitoring is required by TD 24for traffic control systems on trunk roads with a speedlimit of 40 mph or greater, or where the 85th percentilespeed is in excess of 35mph.

5.4.2 The design and maintenance of anyautomated fault monitoring system must in itself ensurethat the system has a high availability record. It isrecommended that faults in monitoring instationsshould be treated as urgent.

5.5 Inspections

5.5.1 Procedures for routine site inspections aredescribed in TD 24. Their purpose is to detectoperational failure and to identify physical oroperational deterioration. The items listed forinspection or test cover:

• equipment operation;

• presence of relevant documentation;

• physical condition of equipment (includingmechanical and electrical condition);

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• physical condition of signs and road markings;

• vegetation that could obscure signs or signals.

5.5.2 It is usual practice for some if not all theitems listed for inspection to be assigned to amaintenance contractor as periodic inspections.Authorities may choose to assign certain items forinspection to different contractors or their ownpersonnel.

5.5.3 Complete inspections are required at leastevery twelve months with specific items requiringinspections at intervals no greater than six months. Themaintenance authority should specify the preciseintervals for inspections in procedures and maintenancespecifications. It is recommended that some leeway isgranted to the contractor. To minimise the risk ofexposing equipment to the elements, annual inspectionsrequiring the opening of equipment cabinets should, ifpossible, be scheduled outside the winter months.

5.5.4 Highway Authorities should take steps toensure that all inspections are carried out effectively,possible by supplementing the maintenance contractor’sinspections with a programme of independent checks.The authority may also need to periodically review theoverall operation of an installation to establish that thedesign and configuration are still appropriate to thecircumstances of the site.

5.5.5 It is recommended that all inspections shouldbe recorded during the progress of the inspection onforms comprising a simple checklist and identifying thedate, time and individual involved in the inspection.

5.5.6 Inspection procedures should be periodicallyreviewed to ensure that tests and inspectiondocumentation evolves with changing equipment andtechnology.

5.6 Monitoring

5.6.1 A pro-active approach to the monitoring ofthe overall effectiveness of traffic control andinformation systems is recommended, leading tomeasures to maintain or improve performance.Feedback resulting from visual monitoring ofconditions on site by staff members and the policeshould be encouraged. Such feedback can beparticularly useful for information obtained outsideoffice hours.

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5.6.2 The quality of feedback could be maximisedby issuing a guide to reporting faults on roadsideequipment to official bodies such as the police.

5.6.3 Information from the general public can beencouraged through publicity, notices on street furnitureand the provision of a freephone number to acceptinformation.

5.6.4 More formal monitoring is possible throughstudies of:

• system logs;

• fault records; and

• accident records.

5.6.5 Close liaison between accident monitoringspecialists, system operators and designers isrecommended. Sharing information between partiesmay allow the cause of an accident trend to beidentified. Sites displaying a particular accident historymay warrant special attention on the part of operatorsand design staff.

5.7 Routine and Non-routine Maintenance

5.7.1 TD 24 (DMRB 8.1) specifies procedures forroutine maintenance covering:

• inspection and replacement of electro-mechanicalparts;

• bulk lamp changing; and

• lens cleaning.

5.7.2 The standard also lists the requirements fornon-routine maintenance. It states that cover should beavailable on a 24-hour day, 7-day week basis to makesafe all defects that present a safety hazard. Thestandard also gives fault category definitions for trunkroads, but response and repair times are left to themaintenance authority that should define them throughtheir maintenance contract specifications andprocedures.

5.7.3 The control of system data by operatorsshould be the subject of quality assurance procedures toensure that a recent data back up is available at all timesready for re-loading.

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5.8 Maintenance Contracts

5.8.1 Tenderers for maintenance contracts shouldbe carefully selected to ensure that only competentorganisations are invited to tender. Tenderers should beconsulted to establish the time required between awardand commencement of contract for mobilisation.

5.8.2 The contract documents should provide acomplete description of conditions and workingarrangements required by the authority. They shoulddefine the contract period, which could be fixed oropen.

5.8.3 Maintenance contracts for periods exceedingtwelve months will usually contain a price fluctuationclause.

5.8.4 The documents should specify:

• location and inventory of equipment to bemaintained;

• fault response periods;

• inspection procedures and periods for inspection;

• penalties for non performance;

• documentation requirements;

• fault reporting procedures.

5.8.5 There should be, within the contract,conditions to ensure that if fault response, inspectionsand routine maintenance tasks are not carried out withinthe specified periods, then escalating penalties will beapplied. These should be index-linked to themaintenance costs of the overall contract.

5.8.6 Allowance should be made within thecontract document for the changeover betweenmaintenance contractors, which may be required eitherwhen the contract has run its term or circumstanceswarrant the premature termination of a contract. It isimportant that the period of notice to terminate thecontract provides a sufficient period to appoint a newcontractor and for mobilisation of the new contractor’sresources, whilst being sufficiently short to effectivelycurtail a contract where the contractor’s performancehas fallen below an acceptable level.

5.8.7 Items requiring replacement during thecourse of maintenance should be on the principle of likewith like, i.e. identical, unless agreed otherwise with

5/4

the client and be subject to full Departmental approval.When the replacement is not identical, care should beexercised to ensure that the original design intentionsare not compromised.

5.8.8 It is recommended that the maintenancecontractor is held responsible within the contract forhandling and dispatching/receiving all warranty itemsfor repair.

5.8.9 The contract should make provision forregular formal meetings with the contractor’s managers,to discuss problems as they arise and reviewperformance. It is recommended that such meetingsshould take place at intervals no greater than twelvemonths.

5.9 Documentation

5.9.1 Those responsible for the implementation ofmaintenance should have access to full documentationand details of each site/system to be maintained. Detailcontained in the Design File, assembled through the lifeof the traffic control equipment, will be the source ofthis information.

5.9.2 TD 24 requires that there should be recordsheld in the offices of the supervising engineer and themaintenance contractor’s depots providing a completehistorical record over five years and covering:

• site layout;

• equipment hardware and software;

• configuration data;

• operational settings; and

• fault history.

5.9.3 Documentation that should be available onsite includes:

• equipment and cabling layout;

• current control equipment settings;

• site-specific safety instructions; and

• log book detailing maintenance history.

5.9.4 The owner of the equipment is normallyresponsible for providing the documentation (includinglog books) for on-site and office use.

May 2006



5.9.5 Comprehensive records of all faults shouldbe maintained and regularly reviewed to identify repeatfaults or abnormal fault frequencies.

5.9.6 There is a legal requirement that recordsfrom sealed contracts be kept for a twelve yearminimum period and unsealed contracts for a minimumof six years.

5.9.7 The documentation available to operators oftraffic control or monitoring systems should includecomprehensive manuals covering:

• system operation under normal operatingconditions;

• facilities for detecting and diagnosing faults; and

• operator facilities for changing the systemconfiguration.

5.10 Safety

5.10.1 All reasonable steps should be taken toensure the safety of maintenance personnel and thepublic during maintenance. TD 24 summarises thestatutory requirements for road safety and electricalsafety that should be integrated with the maintenanceauthority’s specifications and procedures. Theseprocedures should ensure that site operatives areconversant with good practice necessary to safeguardsafety. This legislation includes:

• CDM regulations;

• Health and Safety at Work etc. Act;

• Chapter 8 of the Traffic Signs Manual;

• BS7671; and

• Electricity at Work Regulations.

5.11 Test Equipment

5.11.1 The requirements for the staff of theoperating organisation to have access to test equipmentshould be considered during the design phase. Thenecessary test equipment, documentation and trainingshould be purchased before the system is brought intooperation.

5.11.2 The system maintenance procedures orcontracts should cover test equipment includingcalibration and battery re-charging or replacement.

May 2006 5/5


May 2006

Chapter 6Decommissioning

6/1

6. DECOMMISSIONING

6.1 Considerations

6.1.1 When systems are decommissioned, thefollowing need to be considered:

6.1.1.1 Any relevant waste disposal legislation shallbe complied with where appropriate.

6.1.1.2 The health and safety of the travellingpublic, emergency services personnel, maintenanceoperatives and general public shall be protected at alltimes.

6.1.1.3 Negative environmental impact should beminimised wherever possible. This includes suchconsiderations as the prevention of ground water or aircontamination, the minimisation of greenhouse gasrelease to atmosphere etc.

6.1.1.4 Care shall be taken to identify any items thatcontain hazardous substances that are covered byspecific handling or disposal legislation. Any itemscontaining such substances shall be handled and/ordisposed of in full compliance with the relevantlegislation.

6.1.1.5 Item re-use should be considered, providedthat safety and functional requirements can bemaintained. The financial and environmental costs ofitem recovery, including removal, transportation,storage, refurbishing and re-installation should beincluded in this consideration.

6.1.1.6 Where suitable recycling processes areavailable then these should be considered in preferenceto unprocessed disposal.

6.1.1.7 The disposal of items via incineration orland-fill should be regarded as the last resort andundertaken in a safe, legal and responsible manner. Thismay necessitate the use of reputable waste managementorganisations.

6.1.1.8 Decommissioning operations shall leave anysite in a safe, stable and tidy condition. In particular,care should be taken to remove any hazards to humansor the environment and also to remove any items thatcould be used illegally.


TS

Chapter 7Reference Documents

7.1 Legislation and Regulations

Building Regulations 2000 (SI 2000 No. 3335)

Building Regulations (Northern Ireland) 2000 (SR 2000No. 389)

Consumer Protection Act 1987 (1987 C43)

Construction (Design and Management) Regulations(1994) (SI 1994 No. 3140)

Electricity at Work Regulations 1989 (SI 1989 No. 635)

Electricity at Work (Northern Ireland) Order 1991(SR 1991 No. 13)

European Directives:

• Low voltage

• EMC

• Telecomm Terminal Equipment

• Machinery Directive

• Safety Directive

• CE Marketing Procedure

• Product Liability

Health and Safety at Work etc. Act 1974 (1974 C37)

Health and Safety at Work (Northern Ireland) Order1978 (SI 1978 No. 1039)

The Disabled Persons Act 1981

The Disabled Persons (Northern Ireland) Order 1982

The Highways Act 1980

The Management of Health and Safety at WorkRegulations 1992

The New Roads and Streetworks Act 1991

The Roads (Scotland) Act 1984

7. REFERENCE DOCUMEN

May 2006

The Roads (Northern Ireland) Order 1993 (SI 1993 No.3160) (N.I. 15)

The Road Traffic (Northern Ireland) Order 1995(SI 1995 No. 2994) (N.I. 18)

The Road Traffic Regulation Act 1984

The Road Traffic Regulation Order (Northern Ireland)1997 (SI 1997 No. 276) (N.I. 2)

The Sale of Goods Act (1979 C.54)

The Streetworks (Northern Ireland) Order 1995

The Traffic Signs Regulations and General Directions2002 (SI 2002 No. 3113)

The Traffic Signs Regulations (Northern Ireland) 1997(SR 1997 No. 389)

The Zebra, Pelican and Puffin Pedestrian CrossingRegulations and General Directions.1997 (SI 1997 No.2400)

7.2 Other Notes, Standards and Specifications

BS 7671 Requirements for Electrical Installations (IEEWiring Regulations, Sixteenth Edition)

BS 6100 Glossary of building and civil engineeringterms, subsection 2.4.1 - Highway engineering : 1992

HSE Avoiding Danger from Underground Services

Institution of Electrical Engineers; Safety RelatedSystems

BS EN 61508 Functional Safety of Electrical/Electronic/Programmable Electronic safety-relatedsystems

The Traffic Signs Manual

Specification for Highway Works

TRG 0600 – Self-Certification Procedures for StatutoryApproval of Traffic Signal Control Equipment

TR 2500 – Specification for Traffic Signal Controller

7/1



TR 2507 – Performance Specification for KerbsideDetection Systems for use with Nearside Signals andDemand Units

TR 2504 – Performance Specification for VehicleDetection Equipment for Vehicle Actuated PortableTraffic

TR 2505 – Performance Specification for AboveGround Vehicle Detector Systems for use at PermanentTraffic Signal Installations

TR 2506 – Performance Specification for AboveGround On-Crossing Pedestrian Detection Systems

TR 2512 – Performance Specification for BelowGround Vehicle Detection Equipment

MCH 1969 – Traffic Control System Design for AllPurpose Roads (Compendium of Examples)

The following documents are contained in theDesign Manual for Road and Bridges:

TD 7 – Statutory Approval of Traffic ControlEquipment (DMRB 8.1.1)

TD 24 – All-Purpose Trunk Roads Inspection andMaintenance of Traffic Signals and AssociatedEquipment (DMRB 8:1.1)

TD 33 – Use of Variable Message Signs on All-Purposeand Motorway Trunk Roads (DMRB 8.2.2)

TD 50 – The Geometric Layout of Signal-ControlledJunctions and Signalised Roundabouts (DMRB 6.2.3)

TA 60 – The use of Variable Message Signs on All-Purpose/Motorway Trunk Roads (DMRB 8.2.2)

HD 46 – Quality Management Systems for HighwayDesign (DMRB 5.2.1)

HD 19 – Road Safety Audit (DMRB 5.2.2)

TA82 – The Installation of Traffic Signal andAssociated Equipment (DMRB 8.1.1)

Traffic Advisory Leaflets

TAL10/93 – ‘Toucan’, an unsegregated crossing forpedestrians and cyclists

TAL5/96 – Further development of advanced stop lines

TAL3/97 – The ‘MOVA’ Signal Control System

TA

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L4/97 – Rising Bollards

L4/98 – Toucan crossing developments

L7/99 – The ‘SCOOT’ Urban Traffic Control System

L8/99 – Urban Safety Management using SafeNET

L16/99 – The Use of Above Ground Vehicletectors

L7/00 – SCOOT Gating

L8/00 – Bus Priority in SCOOT

L9/00 – SCOOT Estimates of Emissions fromhicles

L1/01 – Puffin Pedestrian Crossings

L6/01 – Bus Priority

L5/01 – Traffic Calming Bibliography

L1/02 – The Installation of Puffin Pedestrianossings

L2/03 – Signal Control at Junctions on High Speedads

L3/03 – Equestrian Crossings

L5/05 – Pedestrian facilities at Signal-Controllednctions (parts 1-4)

L1/06 – General Principles of Traffic Control byght Signals

affic Advisory Leaflet – Traffic Light Signalslevant Publications

Addresses

partment for Transportaffic Management Divisioneat Minster House Marsham Streetndon1P 4DR

ghways Agency Floor

3 Buckingham Palace Roadndon1W 9HA

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Highways AgencyTemple Quay House2 The SquareTemple QuayBristolBS1 6HA

7.4 Document Sources

7.4.1 The following are available from TSO(Formerly The Stationery Office):

Design Manual for Roads and Bridges(DMRB documents are downloadable fromwww.archive2.official-documents.co.uk/document/deps/ha/dmrb/)LTNs,Regulations,Acts of Parliament,Traffic Signs Manual

7.4.2 Department for Transport

Traffic Advisory Leaflets (TALs)Available to download from www.dft.gov.uk

7.4.3 Highways Agency

TR specificationsMCE, MCH documentsAvailable to download from www.tssplansregistry.org

May 2006 7/3



7.5 Application Guide for Design Manual for Roads and Bridges and Other Documents

* If appropriateN With special requirements for Northern Ireland Traffic Signals PedestrianS For use only in Scotland Crossings

Document

HD19 Road Safety Audits 5 X X X X X X X

HD46 Quality Management Systems for Highway Design 5 X X X X X X X

SH6 Criteria for Traffic Light Signals at Junctions (Scotland) 8 S

TA15 Pedestrian Facilities at Traffic Signal Installations 8 * * X

TA16 General Principles for Control by Traffic Signals 8 X X

TA68 The Assessment and Design of Pedestrian Crossings N(i) LTN1/95 The Assessment of Pedestrian Crossings 8 X X X(ii) LTN2/95 The Design of Pedestrian Crossings X X

TA82 Installation of Traffic Signals and Associated Equipment(LTN1/98) 8 X

TA86 Layout of Large Signal Controlled Junctions 6 X X

TA91 Provision for Non-motorised Users 8 X X

TD7 Type Approval of Traffic Control Equipment 8 X X X

TD24 All-Purpose Trunk Roads Inspection and Maintenance ofTraffic Signals and Associated Equipment 8 X X

TD33 Use of Variable Message Signs on All-Purpose and MotorwayTrunk Roads 8 X

TD35 MOVA System of Traffic Control at Signals 8 * *

TD50 The Geometric Layout of Signal-Controlled Junctions andSignalised Roundabouts 6 X

TA60 The Use of Variable Message Signs on All-Purpose/MotorwayTrunk Roads 8 X

TAL4/91 Audible and Tactile Signals at Pelican Crossings X

TAL5/91 Audible and Tactile Signals at Signal-Controlled Junctions X

TAL10/93 ‘Toucan’, an unsegregated crossing for pedestrians and cyclists X

TAL5/96 Further development of advanced stop lines X

TAL3/97 The ‘MOVA’ Signal Control System X X

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* If appropriateN With special requirements for Northern Ireland Traffic Signals PedestrianS For use only in Scotland Crossings

Document

TAL4/97 Rising Bollards X

TAL4/98 Toucan crossing developments X

TAL7/99 The ‘SCOOT’ Urban Traffic Control System X X

TAL8/99 Urban Safety Management using SafeNET X X

TAL16/99 The Use of Above Ground Vehicle Detectors X X

TAL6/01 Bus Priority X X

TAL7/00 SCOOT Gating X X

TAL8/00 Bus Priority in SCOOT X X

TAL1/01 Puffin Pedestrian Crossings X X X

TAL1/01 SCOOT Estimates of Emissions from Vehicles X X

TAL5/01 Traffic Calming Bibliography X X X

TAL1/02 The Installation of Puffin Pedestrian Crossings X X X

TAL 2/03 Signal Control at Junctions on High Speed Roads X X X X X

TAL 3/03 Equestrian Crossings X X X X X X X

TAL5/05 Pedestrian facilities at Signal-Controlled Junctions (parts 1-4) X X X X X X X

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February 2007

8. HISTORY

8.1 Issue of MCH 1969

April 1999

8.2 Issue of TA 84/01 as part of DMRB

February 2001

8.3 Issue of TA 84/06

May 2006

Chapter 8History

8/1


May 2006 9/1

9. ENQUIRIES

All technical enquiries or comments on this Advice Note should be sent in writing as appropriate to:

Chief Highway EngineerThe Highways Agency123 Buckingham Palace RoadLondon G CLARKESW1W 9HA Chief Highway Engineer

Chief Road EngineerTransport ScotlandVictoria QuayEdinburgh J HOWISONEH6 6QQ Chief Road Engineer

Chief Highway EngineerTransport DirectorateWelsh Assembly GovernmentLlywodraeth Cynulliad CymruCrown Buildings M J A PARKERCardiff Chief Highway EngineerCF10 3NQ Transport Directorate

Director of EngineeringThe Department for Regional DevelopmentRoads Service HeadquartersClarence Court10-18 Adelaide Street G W ALLISTERBelfast BT2 8GB Director of Engineering

Chapter 9Enquiries


E COSTING – WORKED

Appendix ALife Cycle Costing – Worked Example

APPENDIX A LIFE CYCLEXAMPLE

A1 Introduction

A1.1 Assume a set of traffic signals with remotemonitoring installed as a temporary solution for aperiod of 7 years. A typical analysis might be preparedas follows. The annual costs are assumed to be incurredat the beginning of each year so the first year’s costs arenot discounted, the second year’s costs are discountedby one year, etc. The decommissioning is carried out atthe end of the seventh year and is discounted by the fullseven years.

A1.2 The figure taken for annual maintenance includesthe costs of regular re-lamping and an allowance fordetector replacements as well as the normal contractmaintenance. The total amount for maintenance is lessthan the ‘10% of initial cost’ rule of thumb because aproportion of the initial cost is in non electronichardware (such as poles and signs) which have a lowermaintenance requirement.

A1.3 The Discount Rate used is as advised by theDepartment for use in COBA. This is currently 6%.

A2 The initial cost is made up of:

Equipment £20,000Installation £ 5,000Civils work £25,000Design costs £ 4,000

----------Total £54,000

Regular annual costs:

Maintenance £ 700Energy £ 300Comms. £ 170‘Insurance’ Repairs £ 150Staff support £ 300

---------Total £1,620

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A3 Decommissioning

Cost of removal £1,000Residual value (£5,400)

---------Total (£4,400)

A4 Net Present Cost calculation

Cost Discounted

Initial £54,000 £54,000Year 1 £ 1,620 £ 1,620Year 2 £ 1,620 £ 1,523Year 3 £ 1,620 £ 1,431Year 4 £ 1,620 £ 1,345Year 5 £ 1,620 £ 1,265Year 6 £ 1,620 £ 1,189Year 7 £ 1,620 £ 1,117Decommissioning

(£4,400) (£ 2,853)-----------

Net Present Cost £66,343

The fictional costs quoted above are typical for 2003,but should be regarded as indicative only, as prices canvary greatly by area and contract. Designers shouldprepare life cycle costings using specific local data.

A/1


OF STANDARD TERMS

Appendix BGlossary of Standard Terms

APPENDIX B GLOSSARY

B1 Introduction

B1.1 This Glossary brings together definitions ofterms used in traffic control and associated areas oftraffic engineering. Some of these terms are included inBS 6100: Glossary of Building and Civil EngineeringTerms subsection 2.4.1 : 1992 Highway Engineering.Some of the same terms are defined in other publishedstandards and advice notes, often with slightly differentdefinitions. This Glossary aims to provide definitionswhich are self-consistent and accurately reflect currentusage.

B2 European Terms

B2.1 With the harmonisation of standards andspecifications within Europe, new documents are beingproduced which exist in three languages, English,French and German. There is no agreed standard ofequivalents between terms used in the three languagesbut some established UK terminology has been changedin these documents to bring them closer to the term orconcept used in other languages.

Particular differences in the English versions ofEuropean Standards and Specifications include:

i. the use of ‘yellow’ in place of ‘amber’ as thiscorrelates with colour definitions in otherinternational specifications;

ii. the use of ‘signal group’ in place of ‘phase’ toavoid the confusion set out above;

iii. the use of ‘optical unit’ in place of ‘aspect’ for anelement of the signal head;

iv. the use of ‘background screen’ in place of‘backing board’.

In this document, standard UK terms are used anddefined to accord with other specifications, standardsand regulations currently in use.

B3 Phases and Stages

B3.1 The terms ‘phase’ and ‘stage’ often give rise toconfusion and misuse. The concept of ‘stage’ is of aparticular pattern of movements permitted by the traffic

May 2006

signals. The signal cycle is made up of a series ofstages.

B3.2 Confusion arises because the term ‘phase’ is usedto express the concept of ‘stage’ in some other Englishspeaking countries such as Australia and the USA.Furthermore confusion arises from the fact that withsimple signals the two terms can often be interchangedwithout penalty.

B3.3 With more complex control, where the number ofstages does not equal the number of phases, thedistinction between stage and phase is important.Control may be ‘staged based’ or ‘phase based’.

B3.4 In each case the controller selects a stage. Understage control, a specific stage is demanded. Underphase control, a phase is demanded and the controllerselects the most appropriate stage from the alternativeswhich cause that phase to run.

B3.5 Within the traffic signal controller, the term‘phase’ is extended to cover the electronic equipment,which controls the ‘sequence of conditions’ which makeup the phase.

B3.6 For several reasons, particularly the need for redlamp monitoring of individual approaches, it is nowconventional that opposing traffic streams whichalways run together in the signal cycle are controlledseparately by the controller. Although in trafficengineering terms the opposing streams share the samephase, in the controller they are treated as separatephases.

B4 Definitions

B4.1 Standard terms used for traffic control are shownbelow together with their definitions:

Term Definition

141 form Configuration forms for a trafficsignal controller formerly meetingspecification TR 0141 (nowsuperseded by TR 2210). HAreference for these forms is MCH1827.

B/1



Term Definition

arterial Reversion to a selected stage in thereversion absence of demands.

aspect (signal A single optical unit, which, whenaspect) illuminated, displays a single

colour or symbol.

audible signal A device producing a sound toindicate right of way topedestrians.

availability The availability of a system is theamount of time the system isfunctioning and available foroperational use expressed as apercentage of the total time.

backing board A board mounted behind or arounda signal head to increase contrastand improve visibility (referred toas ‘background screen’ in BS ENspecifications).

blackout A period in a pedestrian sequencewhen neither the red nor the greenman symbol is illuminated.

bleep and A distinctive audible signal systemsweep designed to give clear directional

clues over a restricted distance foruse at closely spaced pedestriancrossings where it is important notto give a misleading indication.

bleeper A device for producing an audiblesignal.

box sign A regulatory sign (such as aprohibited movement sign)designed to be mounted alongside asignal head.

bracket A device for mounting a signalhead on to a signal pole.

bus priority A strategy for reducing delay tobuses.

Term Definition

absolute offset The offset between a signalledjunction and a common referencefor a controlled area.

acceptance In this document ‘acceptance’relates to the agreement that theSystem complies with therequirements of this specificationand of this Code of Practice. Itshould not be confused with‘Taking Over’ which impliesacceptance for contractual orpayment purposes.

all-purpose Road for the use of all classes ofroad traffic.

all red A condition of traffic signals whereall movements receive a red signal.

all-red period Period during the change from onephase green to the next when allphases show red.

amber The particular colour in the yellowpart of the spectrum used in trafficsignals. The same as the term‘yellow’ used in Europeanspecifications.

approach That part of an arm which carriestraffic towards the junction.

Approval The body having delegated powersAuthority for the granting of Statutory

Approval for use on the publichighway of traffic control andinformation equipment (e.g.Secretary of State (DfT) forEngland, the Scottish Ministers(Transport Scotland) for Scotland).

arm One of the highways radiating froma junction.

ARM (abbrev.) Availability, Reliability,Maintainability.

Arrow A signal aspect with a symbolindicating a direction.

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B/3
May 2006
Term Definition

cabinet A box installed on-street to containa controller or other equipment.

cabling The wiring installed on-street toconnect a traffic signal controllerwith the signal aspects and otherequipment.

call The placing of a demand for astage or phase.

call/cancel The function of a detector whichcalls a stage or phase whenoccupied for a specified time butfor which the demand is cancelledif it subsequently becomesunoccupied for a specified timebefore the demand matures.

capacity The maximum flow that canproceed through a certain point in agiven period of time.

carriageway That part of a road or highwayconstructed for the use of vehiculartraffic.

CCTV Closed Circuit Television.

CDM Construction (Design andManagement).

CDM The Construction (Design andRegulations Management) Regulations 1994

(SI 1994 No. 3140).

central reserve A central island separating the twohalves of a dual carriageway.

classified count A count where flows for differentclasses of vehicle are recordedseparately.

CLF A system for co-ordinating the(Cableless timings of signal equipment atLinking adjacent signalled junctions by theFacility) use of clocks synchronised to

mains supply frequency.

Term Definition

COBA Department’s computer programfor Cost Benefit Analysis.

condition The pattern of illumination ofaspects of a signal head at a pointin time.

configurator A software-based device forpreparing the programming formicroprocessor-based traffic signalcontrollers.

conflict At a junction, movements whichcannot proceed at the same timesafely are in conflict.

conflicting Phases which control movementsphases which are in conflict (see

‘opposing phases’).

controller Apparatus that controls andswitches traffic signals.

coordination An arrangement which relates thetimings of the signals at a junctionwith the timings at neighbouringjunction(s).

count An enumeration of vehicles at apoint over a specific time period.

cycle One complete sequence of theoperation of traffic signals.

cycle lane Part of the carriageway indicatedby road markings that is reservedfor cyclists. Cycle lanes may be‘Mandatory’ or ‘Advisory’ intheir legal status as to the exclusionof non-cycle traffic.

cycle time The time taken to complete onecycle.

cycle track A way constituted or comprised ina highway being a way over whichthe public have right of way onpedal cycles only, with or withoutthe right of way on foot.



Term Definition

demand Request for right-of-way for trafficpassing a detector and approachinga red signal.

demand A stage in a signal cycle which isdependent only selected when a demand for it

is registered.

Department The Department for Transport(DfT).

Design File A file of basic information andcertification for a scheme,produced during the design processto provide a record of thedevelopment of the scheme, thedecisions made and the safetyconsiderations.

Design The organisation commissioned toOrganisation undertake the various phases of

scheme preparation andsupervision of construction. Duringthe course of scheme preparationand construction, the identity of thedesign organisation may change.

detector Unit of the vehicular or pedestriandetecting equipment that initiates ademand or extension.

detector loop One or more turns of wire installedin the road surface forming part ofa vehicle detector which relies onthe electromagnetic changescaused by a vehicle.

detector unit The part of the detector which isconnected to a detector loop ortransducer and produces an outputwhen a vehicle is detected.

DfT Department for Transport.

dimming The reduction in brightness ofsignal aspects during hours ofdarkness to reduce glare to roadusers.

B/4

Term Definition

Discount Rate Annual percentage rates used inCost Benefit Analysis to convertthe value of future costs andbenefits to present values.

DMRB Design Manual for Roads andBridges.

duct box A chamber installed in the groundwhich gives access to cable ducts.

ducting The system of ducts carrying thecabling at a junction.

dummy phase A software device, within thecontroller, which may be used tocontrol traffic movements whichare not separately signalled. It doesnot have any associated trafficsignals.

duplicate A second primary signal mountedprimary signal on the right hand side of the

carriageway.

early cut-off A condition in which one or moretraffic streams, that were runningduring the preceding stage, arestopped whilst one or more othertraffic streams are allowed tocontinue moving.

early start An alternative term for ‘late start’.

EC European Commission.

effective green For a given actual green period, thelength of green time, which whenmultiplied by the saturation flow,represents the maximum amount oftraffic which will be able to pass inthat green period.

EMC Electromagnetic Compatibility.

exit At a junction, the portion of an armwhich carries traffic away from thejunction.

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Term Definition

extension Continuation of the green signalthat results from a request made bya vehicle or pedestrian that hasright of way. (May also be appliedto a red signal.)

Failure Mode An analysis of a system, whichEffects investigates the possible modes ofAnalysis failure and assesses the effects of

such failures.

fall back The control strategy adopted by acontrol system when the preferredstrategy becomes faulty.

FAT Factory Acceptance Test.

Fault A documentation system (usuallyManagement computer software) for theSystem recording and analysis of the faults

reported in a system and theactions taken in response to them.

filter arrow A green arrow which appears witha red (or amber or red/amber)signal to give right of way to aspecific movement.

fixed time Traffic signal control where theduration of the red and greensignals and the length of the cycleis fixed.

flare The local widening of an approachclose to the junction.

flashing Intermittent operation of a signalaspect.

flow The rate of passing of vehicles at apoint (expressed in pcu or vehiclesper hour).

footpath A way over which the public havea right of way on foot only, notbeing a footway.

May 2006

Term Definition

footway A way comprised in a highwaywhich also comprises acarriageway over which the publichas a right of way on foot.

functional A type of system specificationspecification where the functions of the system

are specified rather than themethod of achieving thosefunctions.

gantry A frame in the shape of a portalused to mount signs or signals.

gap The difference in time or spacebetween the back of a vehicle andthe front of the following vehicle.

gating The use of traffic signals to restrictthe flow of traffic at a point withthe aim of improving the efficiencyof traffic flow at a downstreampoint.

green The colour of the aspect givingright of way at signals.

green arrow A symbol incorporated in a greenaspect to indicate permitteddirection of movement.

green wave A control strategy for a linearsystem of traffic signals whichattempts to synchronise the start ofgreen at a junction with the arrivalof a platoon from the precedingjunction.

group timer A device controlling the timeperiods for a signal group.

guard railing Railing installed on footways andislands to direct pedestrians to thecorrect crossing points.

HA Highways Agency.

B/5



Term Definition

Hazard List As part of a Risk Analysis, a list offeatures of a scheme which couldhave an implication for health andsafety.

headway The difference in time or spacebetween the front of a vehicle andthe front of the following vehicle.

Health and A document (as required by theSafety Plan CDM Regulations) which contains

details of the scheme, anassessment of risks to health andsafety to persons involved in, oraffected by, the construction of thescheme, and arrangements forensuring, as far as is reasonablypracticable, the health and safety ofsuch persons.

high speed A road where the 85th percentileroad approach speeds at a junction are

35mph (56km/h) or above.

highway Way over which the public hasright to pass. The right may berestricted to specific classes ofvehicle.

hood See ‘visor’.

housing See ‘cabinet’.

IEC International ElectrotechnicalCommission.

IEE Institution of Electrical Engineers.

indicative A green arrow indicating thatgreen arrow vehicles may proceed in the

direction shown which is alsocovered by a full green signal.Opposing traffic has been stopped.

intergreen Period between the end of the(period) green signal giving right of way for

one phase, and the beginning of thegreen signal giving right of way forthe next phase.

B/6

Term Definition

intergreen On a vehicle actuated controller, amatrix matrix of intergreen timings

between pairs of phases.

interstage The period between the end of oneperiod stage and the start of the next

stage.

invitation The period of display of a steadyperiod green man to pedestrians at traffic

signals.

island Raised area on the highway,usually at a road junction, shapedand located so as to direct trafficmovement.

ISO 9001 One of the ISO 9000 series ofinternational standards concernedwith Quality Management andQuality Assurance with specificreference to the quality systemswhere a supplier’s capability todesign and supply a conformingproduct needs to be demonstrated.

isolated Control of a signalled junctioncontrol where the timings are not related to

neighbouring junctions.

junction The meeting point between two ormore roads. (Note: no distinction isusually made between a junctionbeing where roads meet and anintersection being where roadscross.)

lamp The light source in a signal aspect.

lamp A system of checking within amonitoring controller that lamps are operating.

lane A section of an approach markedfor the use of a single file ofvehicles.

May 2006



Term Definition

lane control Overhead signals comprising asignals downward pointing green arrow

and a red cross to indicate thepermitted direction of movementon a reversible traffic lane.

lane indication Road markings in the form ofarrows arrows to indicate which traffic

movement(s) may use a lane.

late release An alternative term for ‘late start’.

late start A condition in which one or moretraffic streams are permitted tomove before the release of othertraffic streams, which are permittedto run with them during thesubsequent stage.

LED Light Emitting Diode.

lens The translucent face of a signalaspect which supplies the colourand symbol (if required) and whichmay control the light distributionof the aspect.

Life Cycle The costing of a system, includingCosting the costs of operation, maintenance

and decommissioning, as well asdesign and construction.

link In a network, a connection betweennodes. In traffic networks, linksbetween junctions may be definedfor particular directions,movements or vehicle types.

LINSIG A computer program for theanalysis of isolated traffic signalsoriginally developed inLincolnshire.

local control A form of control at a signalinstallation which is not subject toinfluences from other junctions orarea control systems.

May 2006

Term Definition

loop detector A detector which operates byanalysing the electromagneticeffects on a buried loop of wirecaused by the presence or passageof a vehicle.

loop feeder Cable connecting a detector loop toits detector unit.

loop tails The straight ends of the wireforming a loop which areconnected to the loop feeder.

lost time The time during a cycle whichcannot be used as effective green toone or more phases.

LTN Local Transport Note.

mast arm A pole being curved or having acantilevered branch to allow a signor signal to be mounted above acarriageway.

maximum The time that a green signal togreen vehicles can continue after a(maximum demand has been made by trafficrunning on another phase.period)

minimum Duration of the green signal,green following the extinction of a red-(minimum amber signal, during which norunning change of signal lights can occur.period)

mode A particular method of operationfor a hardware or software device.

motorway Limited access dual carriagewayroad not crossed on the same levelby other traffic lanes for theexclusive use of certain classes ofmotor vehicles.

B/7



Term Definition

MOVA Microprocessor Optimised VehicleActuated strategy based onminimising stops and delays whichmaximises capacity at a singlecontrolled junction.

movement The traffic taking a specific routethrough a junction from a definedentry to a defined exit.

national The sequence of indications ofsequence traffic signals which are prescribed

by national legislation orregulation.

Net Present The costs (both present and future)Cost of a scheme reduced to a single

present value in a Life CycleCosting analysis using a DiscountRate.

NMCS National MotorwayCommunication System.

node In a traffic network, a junction orother point where it is convenientto identify as the end of a link.

NPC Net Present Cost.

occupancy The proportion of time during(of a detector) which a vehicle is determined to be

present.

offset The difference in time between aspecific point in the cycle at ajunction and a reference point.

opposed right A right turning movement which isturn in conflict with oncoming traffic.

opposing Phases which are not permitted tophases run together by the controller but

which do not control conflictingtraffic movements (see ‘conflictingphases’).

B/8

Term Definition

opposing Traffic proceeding in the oppositetraffic direction.

optical unit The optical components (lens,lamp, reflector, housing) making asingle signal aspect.

OSCADY A computer program for theanalysis of isolated traffic signalsdeveloped by the TRL.

overlap Phases which run in successivestages (e.g. late start, early cut-off).

oversaturation A traffic condition at traffic signalswhere demand exceeds capacity.

Overseeing Either the Highways Agency,Organisation Transport Scotland, the Welsh

Assembly Government or theDepartment for RegionalDevelopment (NI), depending onwhich is responsible for thecontract.

parallel stage Two or more complete sequencesstreams of stages within the same controller

which operate at the same timeenabling two junctions or parts of ajunction to be controlled with orwithout interaction between them.

pcu The basic unit of traffic flow equalto the equivalent of a typical car(passenger car unit).

Pelican A pedestrian crossing using far-crossing side pedestrian indicators with a

flashing amber/flashing green manperiod where vehicles arepermitted to move subject to givingway to pedestrians (PEdestrianLIght CONtrolled crossing).

period A time period in a phase duringwhich there is no change incondition.

May 2006



Term Definition

phantom A false impression that an aspect isilluminated caused by incidentlight being internally reflected backthrough the lens.

phase ‘Sequence of conditions applied toone or more streams of trafficwhich, during the cycle, receivesimultaneous identical signalindications’ (TP56) ‘Set ofconditions that fixes the pattern ofmovement and waiting for one ormore traffic streams during thesignalling cycle.’ (BS 6100 2417509) By extension, the equipmentwithin a controller which controls aphase.

phase diagram A diagram showing (as horizontallines) the sequence of conditions ofeach of the phases at a trafficsignal junction.

plan selection A strategy for the control of anetwork of traffic signals wheretimings are selected from a libraryof pre-calculated plans accordingto traffic conditions.

Planning A nominated person (requiredSupervisor under the CDM Regulations)

whose role is to coordinate andmanage health and safety in thedesign and construction of ascheme.

platoon A group of vehicles movingtogether where the behaviour ofeach vehicle is influenced by thevehicle in front.

platoon The tendency for platoons todispersion extend and break up under free

running conditions.

pocket A short additional lane on anapproach or within a junctionreserved for a specific movement.

May 2006

Term Definition

pole box A box installed in the ground at thebase of a signal pole to give accessto cabling.

portable signal A traffic signal designed to bemoved from place to place.

presence A target being present within thedetection zone.

pre-signal A traffic signal installed in advanceof a junction to control access tothe junction for a particularmovement or type of vehicle in asegregated lane.

primary signal A signal head close to the stop linenormally mounted on the left handside of the carriageway.

PROM Programmable Read Only Memory.

protected A signalled movement (commonlymovement a right turn) where conflicting

movements are held against a redsignal.

Puffin crossing A pedestrian crossing that usesnear-side pedestrian signal headsand an extendable All-Red crossingperiod which is instigated by apush button request accompaniedby a pedestrian detector demand(from Pedestrian User FriendlyINtelligent crossing).

Purchaser The recipient of a product providedby a supplier in a contractualarrangement. This may be theSecretary of State for trunk roadsand motorways or the appropriateHighway Authority or the owner ofa private road, tunnel or bridge.

push button A button which may be pressed toregister a demand.

push button A housing containing a pushbox button. Also ‘push button unit’.

B/9



Term Definition

QA Quality Assurance.

Quality A method of assuring that theAssurance features and characteristics of a

product or service satisfy stated orimplied needs.

Quality Plan A document required under aQuality Assurance scheme whichdefines responsibilities andprocedures in a project to ensurethat the QA requirements are met.

queue A stationary or slow-moving file oftraffic where the progress of avehicle is determined by that of thepreceding vehicle.

RCD Residual Current Device.

red The colour of the aspect giving theinstruction to stop.

red/amber The combination of aspectsappearing before green.

red lamp Lamp monitoring of some or all ofmonitoring the red lamps at a junction.

reflector A curved polished device mountedbehind a lamp to focus the lightthrough the lens.

refuge A island where pedestrians maywait.

regulatory sign A sign indicating a trafficregulation (such as a prohibitedmovement).

relative offset The offset between one signalledjunction and another.

relay An electrical switch using a coiland solenoid which makes orbreaks contacts when the coil isenergised. Other types ofequipment having the samefunction.

T

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B/10

erm Definition

eliability A measure of the ability of asystem, subsystem or item ofequipment to operate without faultsusually expressed as the MeanTime Between Failures (MTBF).

emote A system installed at a signalonitoring controller which checks for faults

in operation and reports themautomatically to a central point.

eserve The difference between theapacity capacity of a junction and the

current demand (usually expressedas a percentage of the currentdemand).

esidual An electrical safety device whichurrent Device compares the current entering a

circuit with the current leaving itand which will isolate the circuit ifthe difference (the residual current)exceeds a given value.

FC A measure of level of use (Ratio ofFlow to Capacity).

ight of way Right of priority attached to trafficat traffic moving in a particular direction orignals) a priority temporarily given to

traffic by signals, signs, pedestriancrossings or other means. See‘right of way (general)’.

ight of way Right of passage for the public orgeneral) class of road user (such as

footways or cycle tracks). See‘right of way (at traffic signals)’.

May 2006



Term Definition

Risk An analysis of the risks to healthAssessment and safety involved in the

construction, operation andmaintenance of a scheme. The RiskAssessment included in the Healthand Safety Plan required by theCDM Regulations deals primarilywith the construction phase of thescheme. Risk Assessments are alsorequired for the operation andmaintenance aspects of a TrafficControl and Information system.

road Any highway and any other road towhich the public has access andincludes bridges over which a roadpasses. (In Scotland the definitionof ‘road’ includes any way overwhich the public have a right ofpassage. See ‘highway’.)

road marking Line, symbol or other mark on aroad surface to regulate, warn,guide or inform road users.

Road Safety A formal procedure for theAudit independent evaluation of highway

schemes before implementation toidentify potential safety hazardswhich may affect road users and tosuggest measures to eliminate ormitigate those problems.

run A phase is said to be running whenit is displaying a green signal. Astage is said to run a phase if thatphase displays a green signalduring that stage.

SA Speed Assessment. A VA controlstrategy for high speed roads whichaffects the changing of the signalsaccording to the speed ofapproaching vehicles.

May 2006

Term Definition

Safety Case The formal presentation ofevidence that a system will be safethroughout its life cycle. It willinclude a Risk Assessment and willbe reviewed at various stages in thelife cycle of the scheme.

Safety Review An independent review of thesafety aspects of a system carriedout after the preliminary designstage and again after the detaileddesign stage. These reviews run inparallel with, and may becombined with, the Stage 1 andStage 2 Road Safety Auditsextended to cover the control andoperational aspects of the proposedsystem.

SAT Site Acceptance Test.

saturation The maximum flow (usuallyflow expressed in pcu or vehicles per

hour) obtained at a stop line duringgreen from a discharging queue.

Scheme A traffic engineering project whichincludes one or more TrafficControl and Information Systems.

SCOOT Split, Cycle, Offset OptimisationTechnique which uses real timetraffic data to minimise stops anddelays for UTC controlled areas.

SDE Speed Discrimination Equipment.A VA control strategy for highspeed roads which discriminatesvehicles travelling above a givenspeed threshold.

secondary A signal beyond the stop linesignal which duplicates the display at the

primary signal.

segmented An arrow signal where the headarrow and shaft of the arrow are

separated to improve legibility ofthe arrow direction.

B/11



Term Definition

serve A demand is said to be ‘served’when the phase to which it relatesreceives right of way.

shadow A gap in traffic downstream of atraffic signal caused by thechanging of the signals.

shuttle A system where signals are used toworking control a one-way section of

carriageway operating inalternating directions.

signal A dynamic indication presented toroad users.

signal display The combination of illuminatedaspects in a signal head whichprovides a control instruction totraffic.

signal face One or more signal heads mountedtogether turned towards a trafficstream.

signal group A group of signal heads controlledby the same phase.

signal head A combination of signal aspectswhich together provide all thesignal displays required for thecontrol of one or more trafficstreams at the same stop line.

signal plan A set of timings for the control of agroup or network of junctions.

signal pole A pole installed at a traffic signalinstallation to support one or moresignal heads (also ‘post’ or‘pedestal’).

signal The sequence of displays shown bysequence a signal head.

signals off A condition of the signals where allsignal lamps are switched off.

B/12

Term Definition

signs The process of grantingauthorisation authorisation for the use of signs

(including traffic signals and roadmarkings) which are not prescribedin the relevant regulations.

solar cell A light sensitive device mountedon signals to initiate dimming ofthe lamps during darkness.

solid state A device having the isolatedrelay switching functions of a relay

achieved by the use of solid-stateelectronics rather than solenoidsand physical switching contacts.

split The division of available greentime within a signal cycle betweenstages.

SRS System RequirementsSpecification.

stage The period within a trafficsignalling cycle that gives right ofway to one or more particulartraffic movements. A stage startswhen the last of its associatedphases commences and ends whenthe first of its associated phasesterminates.

stage diagram A diagram for a signalledcontrolled junction showing bymeans of arrows those movementspermitted in each of the stages.

start up The controlled order throughsequence which signals progress from the

off/standby mode to normaloperation.

Starting delay The time interval between the startof actual green and the start ofeffective green.

May 2006



Term Definition

Statutory The approval for use on the publicApproval highway of the design and

construction of an item ofequipment produced to meet aDepartmental specification andwhere approval is required under agovernment statute, which removesthe need for individual approval ofitems of a similar design.

stool A framework installed belowground on to which a housing ismounted.

stop line A line on an approach indicatingwhere vehicles should stop.

storage Ability for vehicles (usually rightturning) to wait within thejunction.

stream (traffic Vehicles in one or more lanes onstream) the same approach to the controlled

area which, when they have theright-of-way, will move in the samedirection.

stud A square or circular metallic orthermoplastic marker installed on aroad surface to indicate the line ofa pedestrian crossing.

SVD A detector which responds only tocertain vehicles identified by theircharacteristics or by an electronictag. (Selective Vehicle Detector.)

System See Traffic Control andInformation System.

System A procedure for recording that theCertification safety-related good practice of this

Code of Practice has been followedfor an individual system.

May 2006

Term Definition

System Either the Purchaser or aCertifier nominated person who, on behalf

of the Purchaser, monitors theprogress of the design,manufacture and installation of theSystem with particular regard tothe stages outlined in this Code ofPractice relating to safety indesign.

System A detailed statement of theRequirements requirements of a system producedSpecification during the design process, which

will form the FunctionalSpecification for the manufacturerof the system.

tactile An indicator (typically a rotatingindicator cone) which indicates the presence

of a green signal for the benefit ofvisually impaired pedestrians.

tactile paving A type of textured paving whichcan be identified by visuallyimpaired pedestrians to indicate thelocation of a pedestrian crossingfacility.

Technical A file containing information aboutConstruction a product submitted to the relevantFile government authority for approval

for CE marking where the productdoes not fully comply with thespecifications referred to by thedirectives and consequently cannotbe self-certified by the supplier.

temporary A traffic signal using the same typesignal of signal equipment as permanent

signals but which is installed for alimited period of time (e.g. signalsin barrels).

terminal A device which can be connectedto a controller (or other equipment)to allow information to be input orextracted.

B/13



Term Definition

time-distance A diagram for a linear system ofdiagram traffic signals showing the

signalled junctions’ locations onthe ‘distance’ axis and the mainroad signal sequences on the ‘time’axis. This can be used to designand examine ‘green wave’ timings.

time table In a coordinated traffic signalsystem, a list of times and dayswhen control events (such as planchanges) take place.

Toucan A stand-alone combinedcrossing pedestrian/cyclist crossing.

Traffic An assembly of electrical andControl mechanical units, controlled byand electronic hardware, firmware and/Information or software which may includeSystem specific modules such as detectors,

actuating, informatic and signallingequipment configured in such away as to provide a facility forcontrolling or giving information toroad users.

tram signal A signal which controls Light RailVehicles running on-street atsignalled junctions.

TRANSYT An off-line program for predictingthe performance of a network oftraffic signals with a given set oftraffic flows and signal timings. Inconjunction with its in-builtoptimiser, it is used to calculate theoptimum set of timings for a givenset of traffic flows. (TRAfficNetwork StudY Tool.)

Trial The use of equipment under aAssessment temporary and limited approval

granted by the Approval Authorityto allow assessment of new ormodified equipment prior topursuing full Statutory Approval.

TRL Transport Research Laboratory.

B/14

Term Definition

trunk road A road of national importanceadministered by centralgovernment.

UKAS United Kingdom AccreditationService.

Unique Code or type number which clearlyproduct defines a product.identifier

Urban Traffic A system for the central control ofControl electronic traffic control devices inSystem a defined area, which will usually

comprise primarily, but notnecessarily exclusively, trafficsignal installations.

UTC Urban Traffic Control. A method ofcontrolling and managing a numberof traffic signals from onecomputer system.

variable A feature of vehicle actuatedmaximum control which allows the maximumgreen green timing to be varied according

to traffic flow.

variable A sign with a legend which can bemessage sign varied.

variable A feature of vehicle actuatedminimum control which allows the minimumgreen green timing to be varied according

to traffic flow.

vehicle Traffic signalling strategy in whichactuation the duration of the red and green

signals and the time of duration ofthe cycle vary in relation to thetraffic flow into and through thecontrolled area. It is actuated bythe traffic by means of vehicledetection.

May 2006



Term Definition

Visor A device mounted above a signalaspect to prevent incident lightfalling on the lens and reducingcontrast and/or to prevent theaspect being seen by road users forwhom it was not intended (alsohood).

wait indicator An illuminated panel in apedestrian push button box whichindicates that a demand has beenregistered.

walk with A control system where pedestriantraffic phases run with non-conflicting

vehicle phases.

washout The reduced contrast between anilluminated aspect and itsbackground caused by the non-specular reflection of incident lighton the lens.

Webster A method of calculating trafficsignal timings developed by F VWebster and published in ‘TrafficSignals’ (RRL Technical Paper 56by F V Webster and B M Cobbe)1966.

wig wag A signal having two similar aspectswhich are illuminated alternately.

Y The sum of the y values of thecritical traffic stream of each stagefor all the stages in the cycle.

y value The ratio of demand and saturationflow for a traffic stream.

yellow See ‘amber’.

May 2006 B/15


TIFICATION

Appendix CSystem Certification Procedure

APPENDIX C SYSTEM CERPROCEDURE

C1 Overview

C1.1 This system certification procedurespecification was previously issued as MCH 1813 andincluded as an annex to TA 84/01. It has been producedto assist highway and road authorities, consultants andcontractors who design and implement non-motorwaytraffic control and information systems. The main aimsbeing to promote safety and consistency through gooddesign practice. This specification is to be used inconjunction with this Code of Practice for TrafficControl and Information Systems for all-purpose roads.

C2 Introduction

C2.1 This specification sets out a systemcertification procedure for the design and installation oftraffic control and information systems. The partiesinvolved include, but are not limited to, systemdesigners, purchasers, installers and commissioners.

C2.2 This specification should be read inconjunction with the main sections of this Code ofPractice. System Certification demonstrates compliancewith this Code of Practice and provides a formaldeclaration that all reasonable and practicable stepshave been considered at each stage in the design of asystem to ensure that the safety of the road user andother parties is not prejudiced.

C2.3 It is recommended that this specification isused as an ‘aide-memoir’ procedure under whichhighway authorities can record that they have followedthe parts of this Code of Practice relevant to them.However, should it be decided that full systemcertification is to be pursued, then a number offundamental requirements that are mandatory within theCode (see Chapter 2) will need to be satisfied beforethe document can be fully authorised.

C2.4 This specification contains generalinformation and specific advice for the completion ofthe system certificate and the system certificationrecords.

C2.5 Certification of the system should not beregarded as certifying the overall scheme, which maycontain elements other than the system itself. The

csa

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May 2006

ertification applies only to an individual system in itscheme context and does not represent a form of typepproval for similar systems used in other schemes.

2.6 System Certification is not a replacement fortatutory Approval, which is still required for allelevant items of equipment forming part of the system.

2.7 In any scheme contract or close workingelationships with other parties involved in the designnd development of the system, it is recommended thateference to System Certification and documentation isade along with the requirement to comply with the

ertification procedures and to follow the guidanceiven in this Code of Practice.

2.8 It is also recommended that the Systemertification procedure be incorporated into the ISO000 quality assurance procedures being adopted by thearious parties involved in the scheme. This willnclude, but not be limited to, the purchasing,esigning, manufacturing and installing organisations.

3 System Certification Procedure

he System Certifier

3.1 The System Certification procedure isntended to certify that the system has been designed,nstalled and commissioned in accordance with thisode of Practice. In signing the Certificate, the Certifieronfirms that the processes required by this Code ofractice have been carried out (including otherequirements implied by this Code of Practice such asealth and Safety Act requirements, CDM Regulationshere applicable and Road Safety Audits). It does not

mply that the Certifier has personally checked all theafety-related aspects of the design.

3.2 Consequently, the System Certifier should be person who is in a position to know what proceduresave been carried out, knowledgeable enough tonderstand the technical implications of thoserocedures and with sufficient authority to ensure thathey are carried out. This person would normally be theroject Manager or other person responsible foranaging the systems aspects of the scheme. It would

ot normally be a departmental head or chief officer

C/1



unless they had a direct management role in thescheme.

C3.3 This level of responsibility assumes that thenominated System Certifier will in turn ensure that allother nominated personnel involved in the scheme arecompetent and have the appropriate skills to performthe tasks being undertaken. This is particularlyimportant where he/she may have to rely on thesepersonnel for verification that each stage of thecertification procedure has been satisfactorilyaddressed.

C3.4 Where the design work is carried out by adifferent organisation from that carrying out theinstallation and commissioning, it is possible to haveseparate System Certifiers for each part of the work.This would require the System Certificate form to bemodified to indicate the section of the work that isbeing certified, but all the certifiers should sign on thesame form to produce a single certificate for theinstalled system.

C3.5 This procedure can be useful when thedesign is prepared but the installation is deferred forsome reason, or when a consultant prepares a design buta local authority manages installation andcommissioning.

The System Certificate

C3.6 The system certificate (page C/4), whencompleted and authorised, represents formalcertification of the system. Other forms are included toassist the project manager or System Certifier as an‘aide-memoir’ in order to keep track of the stages of theproject and to provide a continuous record of progress.

C3.7 The use of these forms is optional but somearrangement must be provided for the properdocumentation of the various stages of the design andimplementation process. These stages shall beconsidered to be ‘hold points’ in the overall systemcertification procedure and continuation beyond thesepoints only occurs when the specific procedures havebeen properly addressed, as confirmed by completion ofthe appropriate parts of the record forms or equivalentdocumentation.

C3.8 Although the completion of the forms isoptional, the procedures that they are associated withwill have to be fully addressed to meet the minimumrequirements set out in this Code of Practice before aSystem Certification can be signed.

C4Acc

C4.ideandSpeparwhtheCod

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C4.Inscomthe

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C/2

Scheme Information and Systemeptance Certificate

1 This form is divided into two parts. The firstntifies and records the location details of the scheme provides a reference to the System Requirementscification (SRS) and the Design File. The secondt of this form is the acceptance certificate which,en signed, provides confirmation that the design of system has been undertaken in conformity with thise of Practice.

eme Title

2 This entry will be a single sentencecribing the common name or title of the scheme. Formple, it may read, ‘Newfoundland Road/Houltonet signalised junction, Bristol’.

erence Number

3 The number that is entered here will be aque number to the scheme and should only beted specifically as an identifying reference to theeme title and the site address. For example, therence number may be the ‘As Built’ drawingber which is directly associated with the site of the

allation.

ected Completion Date

4 The entry in this box is the date when thetallation is expected to have received its finalmissioning, made live to traffic and handed over to

maintenance organisation.

cription of the Scheme

5 In this box a brief description of the schemel be entered to inform the reader the purpose of theallation, which will further identify the schemeng certified.

Address

6 The entry in this box will be the specificress or addresses of the scheme. It is possible that aeme could encompass more than one specificallation site and may cover an interconnected traffica.

May 2006



System Requirement Specification Reference

C4.7 This box contains a reference for thedocument representing the System RequirementsSpecification. For conventional installations, usingapproved equipment, this may only be a list of the typeof equipment being employed or a drawing referencetogether with a brief summary of the method ofoperation. If the installation is non-conventional, a moredetailed SRS document will be required.

C4.8 Any reviews or amendments that the SRSmay have been subjected to during the design stagesshould be referred to in this box.

Design File Reference

C4.9 If the Design File is a structured documentor a software file representing the supporting designdocuments, the entry in this box could be limited to asimple reference number/descriptor through which thereader can access any information recorded during thedesign life cycle.

C4.10 However, if the file is an assembly of non-collated documents then the reference number/descriptor of each document will need to be included.

Completion Date

C4.11 The completion date is the actual date thatthe scheme had received its final commissioning, wasmade live to the traffic and handed over to themaintenance organisation. This date may notnecessarily be the same as the Expected CompletionDate or the date on which the system certificate isissued.

C5 Stage Record Forms

C5.1 Forms for recording the progress of thecertification process can be found at pages C/5-C/8.The use of these forms is optional but they do provide auseful guide to the type of records which are requiredfor certification.

C5.2 These forms are divided into a table withseven columns. The rows refer to the important‘milestone’ items and documents. The seven columnsrefer to the identification and audit trail of the items ofinformation.

May 2006 C/3



SYSTEM CERTIFICATIONSCHEME INFORMATION AND SYSTEM ACCEPTANCE CERTIFICATE

SCHEME TITLE REFERENCE NUMBER

EXPECTEDCOMPLETION DATE

DESCRIPTION OF THESCHEME

SITE ADDRESS(ES)

SYSTEMREQUIREMENTSSPECIFICATION

REFERENCE COMPLETION DATEAND LOCATIONOF DESIGN FILE

HIGHWAY CONTACTAUTHORITY

SYSTEM CERTIFIER REPRESENTING

SYSTEM I CERTIFY THAT THE SYSTEM HAS BEEN DESIGNED, INSTALLED AND COMMISSIONED IN ACCORDANCECERTIFICATION WITH THIS CODE OF PRACTICE FOR TRAFFIC CONTROL AND INFORMATION SYSTEMSDECLARATION

SYSTEM CERTIFIER’SSIGNATURE

C6 Sample Certificate

May 2006C/4

Volume 8 Section 1

Part 2 TA 84/06

May 200

C7 Sample Preliminary Design Stage Document

ESIGN STAGE

REFERENCE NUMBER

ORGANISATION FILE FILEREFERENCE LOCATION

Appendix C

System C

ertification Procedure

6

SYSTEM CERTIFICATION RECORD – PRELIMINARY D

SCHEME TITLE

ITEM TITLE AND DESCRIPTION REFERENCE AUTHORISED DATENUMBER BY AUTHORISED

PRELIMINARYDESIGN BRIEF

PRELIMINARYLAYOUT

DRAWINGS

RECORD OFNAMES AND

COMPETENCE OFDESIGNERS

SAFETY CASE(INCORPORATING

HAZARD LIST)

SAFETY REVIEWStage 1 Road Safety

AuditStage1 Eexceptions

ReportSystem Review

C/5

Volume 8 Section 1

Part 2 TA 84/06C8 Sample Detailed Design Stage Document

GE

CE NUMBER

N FILE FILEREFERENCE LOCATION

C/6

Appendix C

System C


May 2006

SYSTEM CERTIFICATION RECORD – DETAILED DESIGN STA

SCHEME TITLE REFEREN

ITEM TITLE AND DESCRIPTION REFERENCE AUTHORISED DATE ORGANISATIONUMBER BY AUTHORISED

DETAILEDDESIGN BRIEF

DETAILEDLAYOUT

DRAWINGS

RECORD OFNAMES AND

COMPETENCE OFDESIGNERS

TYPE APPROVALREQUIREMENTS

SPECIFIED

SYSTEMREQUIREMENTSSPECIFICATION

SIGNSAUTHORISATION

Applied for:Granted:

SAFETY CASEREVIEW

CDM PLANPREPARED

SAFETY REVIEWStage 2 Road Safety

AuditStage 2 Exception

ReportSystem Review

Volume 8 Section 1

Part 2 TA 84/06

May 200

C9 Sample Manufacture and Design Stage Document

D SUPPLY STAGE

REFERENCE NUMBER

ORGANISATION FILE FILEREFERENCE LOCATION

Appendix C

System C


6 SYSTEM CERTIFICATION RECORD – MANUFACTURE AN

SCHEME TITLE

ITEM TITLE AND DESCRIPTION REFERENCE AUTHORISED DATENUMBER BY AUTHORISED

EQUIPMENTFUNCTIONAL

SPECIFICATIONFOR SPECIAL

SYSTEMS

EQUIPMENTSTATUTORY

TYPE APPROVAL

QUALITYASSURANCE

PRODUCTCONFORMITY

C/7

Volume 8 Section 1

Part 2 TA 84/06C10 Sample Installation and Commissioning Stage Document

ONING STAGE

NCE NUMBER

N FILE FILEREFERENCE LOCATION

C/8

Appendix C

System C


May 2006

SYSTEM CERTIFICATION RECORD – INSTALLATION AND COMMISSI

SCHEME TITLE REFERE

ITEM TITLE AND DESCRIPTION REFERENCE AUTHORISED DATE ORGANISATIONUMBER BY AUTHORISED

NAMES ANDCOMPETENCE OF

SUPERVISIONPERSONNEL

CONTRACTORCOMPETENCE

EVIDENCE OFEQUIPMENTSTATUTORY

TYPE APPROVAL

FACTORY TESTS

TESTER NAME/COMPETENCE

Test schedulesand results

FUNCTIONALTESTS AND

INSPECTIONS

TEST NAME/COMPETENCE

Site check sheets