Post Opening Project Evaluation (POPE) A30 Whiddon Down ...assets.highways.gov.uk/...schemes/...a30-whiddond-down-fya-final.pdf · (formerly Merrymeet roundabout) ... Yes Reduce congestion

Post Opening Project Evaluation (POPE)

A30 Whiddon Down Junction Improvement (formerly Merrymeet roundabout)

Five Years After Study

© GeoPerspectives

Notice

This document and its contents have been prepared and are intended solely for the Highways Agency’s information and use in relation to the Post Opening Project Evaluation of Major Schemes.

Atkins assumes no responsibility to any other party in respect of or arising out of or in connection with this

document and/or its contents.

Post Opening Project Evaluation

A30 Whiddon Down junction improvement – Five Years After

5106230/POPE _ A30 Whiddon Down FYA final i

Contents

Section Page

Executive Summary ii

1. Introduction 1

2. Traffic 6

Forecast vs. Outturn Traffic volumes 16

3. Safety 21

Further Accident Analysis 26

Security 30

4. Economy 32

Scheme costs 33

Benefits 35

Benefit Cost Ratio (BCR) 39

5. Environment 42

6. Accessibility and Integration 64

7. Conclusions 65

Appendices

Appendix A AST and EST 66

Appendix B : Traffic 69

B.1 Further traffic data 69

Appendix C : Statistical Significance Tests on Safety Data 71

C.1 Significance of Difference in numbers of Accidents and Casualties in before and after periods 71

C.2 Significance of changes in Accident numbers Compared with Control site 72

Appendix D : Environment 74

D.1 Sources 74

D.2 Photographic Record of Scheme Including: ES Photomontages and OYA vs FYA comparisons 76

Appendix E : Glossary 82

Appendix F : Tables and Figures in this Report 85

The maps in this document are reproduced from Ordnance Survey material with the permission of Ordnance Survey on behalf of the Controller of Her Majesty's Stationery Office © Crown copyright. Unauthorised reproduction infringes Crown copyright and may lead to prosecution or civil proceedings. Highways Agency Licence No. 100030649. Published 2012.



5106230/POPE _ A30 Whiddon Down FYA final ii

Executive Summary

Scheme description The A30 / A382 Merrymeet Junction improvement was a Highways Agency Major Scheme in

Devon, which opened in December 2006. The scheme was the replacement of a roundabout

between the A30 dual carriageway and the single carriageways of the A382 and C50 at Whiddon

Down, between Exeter and Okehampton in Devon with a two-level, grade-separated junction.

Specific elements of the scheme included:

A new overbridge crossing the A30, just north of the former roundabout where the trunk road lies in a cutting, providing a good ‘fit’ into the landscape.

Four new merge and diverge lanes providing entry and exit for the A30, and allowing all movements.

A realigned link to the minor road C50, which was the former route of the A30 prior to the dualling of the route in the 1970s.

Measures to reduce the impact of the scheme on the local environment, including new planting, earth mound screening and the significant reduction in the overall level of lighting at the junction.

Since opening, the junction has been renamed to Whiddon Down, the name of the nearby village.

This report is part of the Post Opening Project Evaluation (POPE) commission undertaken on

behalf of the Highways Agency (HA). This report has been prepared based on data at the Five

Years After (FYA) stage.

Objectives

Objectives (from Non-technical Summary and Appraisal Summary Table) Objective

Achieved?

Improve safety at the junction by removing problems particularly associated with A30 traffic stopping at the roundabout, including a high rate of fatalities.

Yes

Reduce congestion occurring at the roundabout at peak times, and during the holiday period.

Yes

Reduce journey times for A30 through traffic. Yes

Retain a full movement junction. Yes

Avoid environmental impact on Dartmoor National Park which lies on the highway boundary.

Yes

Reduce environmental effects as far as practicable. Yes

Key findings A30 through traffic now travels straight through the junction without delays.

Scheme has successfully addressed the problem of the accident cluster at the roundabout.

Environmental mitigation measures are establishing satisfactorily.

Summary of Scheme Impacts

Traffic

Since 2008, the A30 has shown traffic growth, unlike the wider trends which have seen traffic on rural A roads and in Devon having fallen year-on-year since 2007.



5106230/POPE _ A30 Whiddon Down FYA final iii

There is a clear underlying trend of traffic growth on the A30 both sides of this junction. The net difference between traffic levels east and west of the junction also shows year-on-year increases since 2008.

In 2011, 32,700 vehicles pass through this junction on an average weekday, an increase of 6% since 2005.

On the non-trunk A road which approaches the junction from Whiddon Down village (the A382) there has been an increase of over 1,000 vehicles per day which reflects the improved access to the trunk road network now provided at this junction. This also includes a 50% increase in the number of Heavy Good Vehicles (HGV).

Turning counts show that around three-quarters of traffic passing this junction is A30 through traffic which benefits from no longer needing to give way at the roundabout and can pass through the junction without needing to slow or stop.

August traffic volumes are the highest of the whole year, due to tourism in Devon and Cornwall. These showed no change in 2011 compared to the period before the scheme was built.

The appraisal of the scheme significantly underestimated the traffic volumes on the A30 in the one year after stage, even assuming high growth.

Five years after opening, the low rate of traffic growth in recent years has meant that observed A30 traffic levels were closer to the forecasts.

Although traffic volumes on the A382 which runs though the village were higher than before the scheme was built, they were close to the high growth forecast level.

Safety

In the post opening period there has been an accident saving of one per year compared with the before period.

A road safety audit suggested that soon after opening, some users experienced problems adapting to the new layout of the junction leading to increased accidents at first. Longer term data from 2008 onwards now shows fewer accidents indicating a successful long-term trend.

Mapping of the accidents shows a cluster at the roundabout before the scheme was built. Accidents on the 0.3 mile short section of the A30 and the junction reduced by 63%, representing a saving of nearly 12 accidents in 4.5 years in the area close to the junction.

No pedestrians or cyclists were injured at this location, either before or after opening.

Observed accident savings at the roundabout were 34% lower than predicted.

Forecasts of fatalities saved through the removal of the roundabout were too high. Later data than that used in the scheme appraisal indicates that although there were a high number of accidents before opening, there was not an unusual severity problem.

Environment

Noise: Traffic flows on the A30 are in line with forecasts and it is assumed that noise due to traffic is as expected. On the A382, numbers of HGVs are 49% higher than before the scheme and noise could be worse than expected for the few properties nearby and for Whiddon Down where no noise impacts were expected as a result of the scheme.

Local Air Quality: Although traffic flows are higher than expected on A382 and A30 east of the junction, overall numbers are low and it is unlikely that they would cause any breach in air quality criteria, especially given the rural nature of the area.

Greenhouse Gases: Negligible increase of 1% additional carbon emissions, similar to forecast.

Landscape: Landscape planting is establishing satisfactorily and subject to ongoing maintenance and management, should reach its longer term objectives for visual screening and landscape integration by the design year of 2021.

Biodiversity: Measures have been taken to reduce the effects of the scheme on protected species and new planting mitigates for the loss of vegetation. Dormice are still present around the junction and are breeding, although at this stage favourable conditions for reptiles to recolonise the habitat areas does not appear to have been achieved.



5106230/POPE _ A30 Whiddon Down FYA final iv

Heritage: Archaeological mitigation was undertaken as proposed in the Environmental Statement including recording of historic hedgerows and very little of archaeological interest was found.

Water: Mitigation measures have been incorporated into the scheme in accordance with Environment Agency requirements and based on the information available there is nothing to suggest that they are performing other than as intended.

Journey Ambience: Road users’ views are largely unchanged as expected. Driver stress has benefited by reduced delays and improved journey time reliability for through traffic, particularly during peak holiday times. Signing has been improved since the scheme first opened.

Accessibility

The scheme was not expected to have accessibility benefits.

The overbridge route facilitates a better crossing of the A30 for cyclists and pedestrians than the former roundabout. However, there are few of these users here and there was no formal provision except a footway on the bridge although there is space for future improvements.

Integration

Scheme is consistent with policies in place at the time of its construction and there has been no significant change since, hence evaluation is a beneficial impact due to its contribution toward improving transport links to regeneration areas in Cornwall and North Devon.

Summary of Economic Performance

All monetary figures in 2002 Prices and values

Pre-scheme forecast Outturn FYA reforecast

Journey Times £23.6m £27.3m

Safety £24.7m £7.4m

Indirect Tax1 £1.2m £0.9m

Total Present Value Benefits (PVB) £48.4m £34.6m

Present Value Costs (PVC) £8.6m £9.5m

Benefit Cost Ratio (BCR) 5.6 3.6

1 Indirect tax revenue increased as a result of the scheme hence increasing the benefits based on the current approach

The investment cost of the scheme was £10.8m in 2002 prices, which was substantially higher than the predicted cost of £7.6m, when it was appraised in 2004.

Journey time benefits were higher than expected due to traffic levels on the A30 being higher than forecast, despite the economic downturn.

Safety benefits, which had been expected to comprise half the benefits, were evaluated to be much lower than expected. This is because the forecasts were based on the prediction of a continuing long-term problem of a high number of both accidents and fatalities at the roundabout without the scheme in place. The lower outturn benefits were based on an observed reduction in accident numbers, whereas the forecasting was based on an unrealistically high rate of fatal and serious accidents at the roundabout.

Outturn Benefit Cost Ratio (BCR) was lower than forecast, but at 3.6 still represents high value for money.



5106230/POPE _ A30 Whiddon Down FYA final 1

1. Introduction

Background to Scheme

1.1 The A30 trunk road runs between Exeter in Devon and Penzance in Cornwall. This report

concerns a Highways Agency scheme to improve one of the last at-grade junctions on the

A30 between Exeter and Okehampton.

1.2 The A30/A382 Merrymeet junction scheme was the upgrading of the existing roundabout

junction to a grade-separated junction where the A30 meets the A382 (a single carriageway)

near Whiddon Down village, just to the north of Dartmoor National Park. The new junction

comprises:

A new overbridge crossing the A30, just north of the former roundabout where the trunk

road lies in a cutting, providing a good ‘fit’ into the landscape;

Four new merge and diverge lanes providing entry and exit for the A30, and allowing all

movements; and

A realigned link to the minor road C50, the former route of the A30, pre dualling in the

1970s.

1.3 Access to Whiddon Down village and Okehampton East Service Area has been maintained.

1.4 The Merrymeet scheme was part of the Highway Agency‘s Targeted Programme of

Improvements (now called Major Schemes) and was fully opened to traffic in December

2006. Since the scheme was constructed the name of it has been changed to the Whiddon

Down Improvement.

1.5 This report is the Five Years After post opening study of the scheme.

Location

1.6 The scheme is located in Devon as shown in Figure 1.1 and is located in Highways Agency

Area 1.

Figure 1.1 – Location of A30 Whiddon Down scheme




Problems prior to the Scheme

1.7 The scheme’s Appraisal Summary Table (AST) summarised the problems at this junction to

be addressed by the scheme as follows:

This is the only roundabout along the A30 Dual Carriageway between Exeter and Okehampton, requiring drivers to slow down and Give Way. The roundabout has an accident problem and suffers frequent delays, particularly during times of peak holiday traffic.

Objectives of the Scheme

1.8 The main objectives of the scheme were to:

Improve safety at the junction by the removal of the roundabout which had a poor

accident record including a high rate of fatalities and its replacement with a

grade-separated junction with better alignments;

Retain a full movement junction between the A30, A382 and the former route of the A30,

north of the junction, the latter two being part of a national high level route;

Relieve the congestion problems at the junction which occurred at peak times and

holiday periods; and

Reduce journey times for A30 through traffic.

1.9 In addition, the scheme’s Environmental Statement (ES) stated that the scheme objectives

were also to reduce as far as practicable the damage to the environment whilst giving due

weight to road safety, engineering design and cost. In particular, the scheme would:

Minimise landtake;

Avoid the Dartmoor National Park, south of the scheme;

Minimise the impact on the Area of Great Landscape Value, north of the scheme; and

Reduce the overall level of street lighting at the junction, compared to the existing

situation, thus reducing the dusk and nighttime impact of this gateway to the national

park.

Scheme description

1.10 The scheme was the improvement of a junction on the A30 and the changes are summarised

in the maps in Figure 1.2.




Figure 1.2 – Scheme Summary

Before junction improvement After junction improvement

Layo

ut

of

jun

cti

on

Desc

rip

tio

n

Prior to the construction of this scheme, this junction was a four-arm roundabout on the A30 linking with the A382 to the south and a minor road (C50) to the north.

The alignments at the roundabout were:

A30 eastbound approach to the roundabout was uphill;

A30 westbound approach was a right-hand downhill bend;

and

The two minor roads both had a downhill approach to the

roundabout.

The roundabout was first constructed as an intermediate point between the first section of A30 dualling in the late 1970s and the next section west of the junction 10 years later. This allowed for changes in the horizontal and vertical alignments of the two schemes.

The scheme comprises a compact grade-separated junction providing all-movements for A30 traffic comprising:

A new overbridge crossing the A30, just north of the former

roundabout where the trunk road lies in a cutting, providing

a good ‘fit’ into the landscape;

Four new merge and diverge lanes providing entry and exit

for the A30, and allowing all movements;

A realigned link to the minor road C50, the former route of

the A30, pre dualling in the 1970s;

Earth banks and tree planting, providing environmental

mitigation; and

Modern lighting.

Access to Whiddon Down village and Okehampton East Service Area (shown as motel on the OS map above) was maintained.




History

1.11 The key dates in the timeline of the scheme are shown in Figure 1.3.

Figure 1.3 – Scheme Key Events Timeline

1.12 The scheme was awarded the HA major projects award for zero reportable accidents in a

year.

Post Opening Project Evaluation (POPE)

Purpose of this Report

1.13 The Highways Agency (HA) is responsible for improving the strategic highway network

(motorways and trunk roads) in England by delivering the Major Schemes programme

(formerly Targeted Programme of Improvements or TPI). At each key decision stage through

the planning process, schemes are subject to a rigorous appraisal process to provide a

justification for the project’s continued development. When submitting a proposal for a major

transport scheme, the Department for Transport (DfT) specifies that an Appraisal Summary

Table (AST) is produced which records the degree to which the five Central Government




objectives for Transport (Environment, Safety, Economy, Accessibility and Integration)1 have

been achieved2. The contents of the AST allow judgements to be made about the overall

value for money of the scheme. The AST for this scheme is presented in Table A.1 of this

report.

Overview of POPE

1.14 POPE studies are undertaken for all Major Schemes. During the planning process, scheme

effects are based on well informed predictions. However, it is vital to identify the strengths

and weaknesses in the techniques used for appraising schemes so that improvements can

be made in the future. For POPE, this is achieved by comparing information collected before

and after a scheme opens to traffic, with predictions made during the planning process.

Outturn impacts are summarised in an Evaluation Summary Table (EST). The EST

summarises the extent to which the scheme objectives have been achieved and the EST for

this scheme is included in Table A.2 of this report.

Sources

1.15 This study is based on the following sources:

Traffic counts and journey times from the Highways Agency’s TRADS and HATRIS

databases;

Traffic surveys commissioned for this study;

Accident records obtained from Managing Agent Contractor (MAC);

Road Safety Audits of the scheme;

A site visits by a transport planner and a landscape architect; and

Reports appraising the scheme, prior to construction;

- A30 Merrymeet Junction Improvement Report of Surveys and Local Model Validation

Report June 2004;

- A30 Merrymeet Junction Improvement Forecasting and Economic Assessment

Report, November 2004;

- Environmental Statement, 2005; and

- Appraisal Summary Table (from Scheme Assessment Report), January 2003.

1.16 Details of the sources for the environmental evaluation are given in Appendix D.2.

1 Objectives at the time this scheme was appraised were defined by the New Approach to Appraisal (NATA)

2 From April 2011, this approach was revised, however POPE is concerned with evaluation against the

appraisal and as such follows the objectives used at that time.




2. Traffic

Introduction

2.1 In order to assess the traffic impact of the scheme, the following section reports on:

Long term traffic volume trends on the A30 in this area;

Flows on the A30 and the surrounding road network;

Turning movements at the junction;

Comparison of forecast and observed traffic volumes and

Journey times.

Data sources

Timing of Data Collection

2.2 Traffic data was collected for the A30 and other roads close to the location of the junction for

the following time periods:

May 2004/5, March 2005 – before construction started

March/April 2008 – one year after scheme opening (OYA)

March 2012 – five years after (FYA)

August 2004, 2007 and 2011 – to study the summer congestion

2.3 Although the scheme opened in December 2006, the ‘one year after’ data was collected for

April 2008 because the winter period has untypical traffic flows. Tourism is important to the

economy of Devon and Cornwall and has significant impacts on the traffic flows on this part

of the A30. As shown later, there are no true traffic neutral months here. Thus traffic figures

presented have been carefully factored to given annual average and are based on dates

which avoid the Easter period3.

2.4 The A30 in Devon is an important holiday route so data has also been collected for August

which is the busiest period of the year on this road.

Sources of Data

2.5 Observed traffic flow data was obtained from:

Highways Agency’s TRADS database– permanent counts on the A30 for the whole

period, as detailed in Appendix B;

A30 Merrymeet Junction Improvement Report of Surveys and Local Model Validation

Report (LMVR) – source of ‘Before’ data for traffic flows on the minor roads, the before

turning count and the forecast traffic flows;

Temporary surveys on minor roads commissioned for this study:

3 Easter fell in late March in 2005 and 2008 so the OYA before and after data was based on April data, but

as Easter 2012 was in April in 2012, for this FYA study we have used data from the early part of March for A30 data for all these years which has then been annualised.




- Temporary traffic counts on the non-trunk roads in the one and five years after

periods; and

- Manual Classified turning counts at the new junction.

2.6 Forecasts of traffic volumes were obtained from the Forecasting & Economic Assessment

Report (2004). As this scheme was considered to be a straightforward safety upgrade, the

modelling of both the traffic and economic aspects were combined into that single report.

National and Regional Trends in traffic

2.7 Before looking at the traffic impacts of the scheme, it is useful to consider the wider context of

the background of the growth a recent decline in traffic levels on a national and regional basis

According to Office for National Statistics figures, the UK the economy entered recession in

the second half of 2008.

2.8 The wider traffic trends over the past decade are summarised in Figure 2.1 and Figure 2.2

based on published DfT data4 compared against changes in Annual Average Daily Traffic

(AADT) on the A30 east of the scheme since 2003. Note that the variation in A30 AADT in

these graphs is presented here proportionate to the traffic indices.

Figure 2.1 – National and Regional Traffic Trends compared with A30 traffic

2.9 This trend graph shows the following key points regarding wider traffic trends and the A30:

There has been a decline in traffic since 2008 both nationally and in the region and

county which include this scheme.

4 Table TRA8904a Estimated traffic volume for all motor vehicles by region/country: Great Britain: 1993 -

2010 (kilometres), and Table TRA2507 Road traffic in Great Britain by road class: Index numbers (kilometres). These have been used to create indices of growth in traffic since 2000.




On the A30 east of this scheme, traffic flows have continued to grow year-on-year since

2008. Given the importance of tourism in this area, it is likely that trends affecting this

part of the economy during this period are an important driving force behind changes in

A30 traffic levels.

Figure 2.2 – National Traffic Trends by Road Type: Rural roads compared with A30 traffic

2.10 This shows how traffic trends on the A30 differ from national trends for roads in rural areas:

Since 2008, the A30 has shown traffic growth, unlike the wider trend which saw traffic on

rural A roads having fallen year-on-year since 2007.

The pattern on minor rural roads is less clear.

2.11 Permanent count sites on the A30 provide long-term data in this area since 2005. This data

has been used to analyse the trend in two-way daily traffic by month as illustrated in Figure

2.3.




Figure 2.3 – Trends on A30 east and west of the junction-by month

2.12 The key points shown here are:

This highlights the extreme seasonality of the traffic flows, with the maximum daily traffic

occurring in August being double the minimum in January. This pattern is consistent for

every year since 2005.

Traffic flows were not impacted by the construction period, despite it being online. This

shows that the disruption during that period was relatively minor for A30 traffic and was

not sufficient to lead to rerouting to the only reasonable alternative of the A38, south of

Dartmoor.

2.13 The extreme variation by month seen in Figure 2.3 obscures traffic growth during this period,

thus we have also looked at the annual figures. Figure 2.4 shows the AADT where there is a

full 12 months of data for the years from 2003 to 2011.

Figure 2.4 – AADT Yearly Trends on A30 east and west from 2003

2.14 Once the seasonal effect is removed, we can see:




There is a clear underlying trend of traffic growth on the A30 both sides of this junction in

the period between the start of construction in late 2005 and 2011.

Most years show growth compared with the previous year.

In 2006, when this scheme was under construction, traffic was reduced which may be

partially due to some rerouting due to delays during construction, but given that the only

alternative strategic routes are either lengthy (in the case of the A38 east of Dartmoor) or

far from straightforward (via non-trunk single carriageway A roads).

Traffic Volumes at locations around the junction

2.15 Traffic volumes on the four arms of the junction before the start of construction then one year

after and five years after opening are shown in Table 2.1 and mapped in Figure 2.5. The

figures presented here are for weekdays (annual average weekday traffic, AAWT) but due to

the importance to tourism-related traffic flows in this area, the 7-day average flows are very

similar. The equivalent AADT flows are shown in the appendix in Table B.2.

2.16 The data for the A30 is taken from Automatic Traffic Count (ATC) data from the first two

weeks of March for the years 2005, 2008 and 2012. This omits the impact of the Easter

school holiday period in all three years.

Table 2.1 – Average Weekday Traffic volumes around the Junction

Location

Average Weekday Traffic (AAWT) % change

Before One Year

After Five Years

After One Year

After Five Years

After

A30 east of jct 28,600 29,600 30,200 4% 6%

A30 west of jct 25,000 26,300 26,400 5% 6%

A382 west of jct 6,400* 6,600 7,500 3% 17%

Minor rd 1,400* 1,100 1,200 -18% -10%

Total Throughput 34,500 35,800 36,800 4% 6%

* AWT before data for the A382 and the minor road are estimates based on the 12hour manual count

taken in May 2004

2.17 For the minor roads the daily figure for before construction is an estimate based a manual

count undertaken in May 2004. The after period counts are based on ATCs from April 2008

and March 2012, excluding the Easter holiday period. All data is factored to give annual

averages.




Figure 2.5 – Weekday Traffic volumes and Total Flow through Junction

2.18 The key points shown in Table 2.1 and mapped in Figure 2.5 are

On weekdays 32,700 vehicles pass this junction, primarily on the A30 trunk road.

Traffic has increased by 6% since 2005

On the A382 which approaches the junction from Whiddon Down there has been an

increase of over 1,000 vehicles per day which reflects the improved access to the trunk

road network now provided at this junction.

The unclassified minor road north of the junction still has relatively low flows.

Turning Movements at the Junction

2.19 Manual turning counts were undertaken at the roundabout before the scheme construction on

weekdays 5th May 2004 and at the new junction one year after opening on 29

th April 2008

and five years after on 27th March 2012. All counts were taken over a 12 hour period from

07:00 to 19:00. Note that these surveys are based on a single day’s observations and are

therefore potentially less representative than the traffic counts presented elsewhere in this

report.




2.20 The results of the surveys are summarised in Table 2.2 and Table 2.3.

Table 2.2 – 12 Hour Traffic movements at junction

Survey year

A30 east of jct A30 west of jct A382 west of

junction

Unclassified minor road east of

junction

Entering A30

towards Exeter

Exiting A30 from

Exeter direction

Entering A30 towards

Okeham.

Exit A30 from

Okeham.

Towards jct

Away from jct

To jct Away

from jct

2004 1,670 1,770 780 770 2,660 2,500 570 640

2008 1,680 1,800 950 690 2,590 2,720 490 500

Change 0% 2% 22% -11% -2% 9% -14% -22%

2012 1,700 1,730 1,010 740 2,630 2,820 470 500

Change 2% -2% 23% -4% -1% 11% -21% -29%

Table 2.3 – Total 12 hour Traffic flows using junction

Survey year Total entering or exiting the A30

Traffic crossing A30 (between A382-

minor road)

A30 through traffic (passing straight

through jct)5

2004 4,990 690 15,790

2008 5,120 830 over 16,000

Change 3% 21%

2012 5,190 1,010 over 17,000

Change 4% 46%

2.21 The key points from the junction movement details are:

Around 5,000 vehicles enter or exit the A30 trunk road from the local road network at this

junction during the daytime.

Most of this traffic enters or exits the A30 in the direction of Exeter.

The movements to and from the A30 show little change since the scheme was opened.

Traffic crossing over the A30 between the A382 and the unclassified road east of the

junction whilst comprising only a small proportion of traffic using the junction shows a

sharp rise. This is possibly due to this traffic making this movement benefiting from

using the new overbridge rather than needing to cross the A30 traffic at the roundabout

as previously.

Around three-quarters of traffic passing this junction is A30 through traffic which benefits

from no longer needing to give way at the roundabout and can pass through the junction

without needing to slow or stop.

5 Post opening data approximated TRADS data west of junction and turning count data for traffic

entering/exiting from the west.




August Traffic on the A30

2.22 Tourism is an important part of the economy of North Devon and Cornwall and this is

recognised as having a large impact on traffic flows on the A30, particularly on the seasonal

variation.

2.23 The yearly trend analysis in the previous section shows that traffic volumes on the A30 are

much higher during August than any other month of the year. Figure 2.6 shows the daily

traffic volumes in August before and after the scheme opened at the count location on the

A30 near Okehampton, west of the scheme.

Figure 2.6 – August traffic volumes by day of week, by direction, west of jct

2.24 The key points from these August traffic bar charts are:

In August, the highest daily traffic flows in this section of the A30 occur on Fridays and

Saturdays.

The spread of traffic flows across the week and by direction clearly reflects the high level

of tourist traffic in which :

- Weekend traffic (including Fridays) is higher than weekdays; and




- Traffic tidality patterns show that westbound traffic, i.e. including the outgoing trips

towards holiday locations, is concentrated on Fridays and Saturdays, while the return

trips for these users although again mainly focussed on Fridays and the weekend, is

slightly more spread through the week.

August Saturday traffic shows the highest daily volumes at over 50,000 vehicles daily,

although this is slightly lower than before opening.

There has been negligible change in the overall August daily traffic volumes on the A30

between the before OYA and FYA periods.

Heavy Goods Vehicles (HGVs)

2.25 Traffic volume data on the A30 in TRADS also includes data classified by vehicle length. In

2007, this database recorded vehicles less than or greater than 5.2m (18ft) in length so this

criterion has also been used for 2011 data.

2.26 Figure 2.7 summarises the numbers of HGVs and what proportion they form of all traffic on

the A30 and is based on March data, excluding the holiday periods.

Figure 2.7 – Average Weekday HGVs on A30

2.27 This shows that the absolute number of HGVs on the A30 east and west of the scheme

increased between 2005 and 2012, but the proportion they form of all traffic remained steady

at just above 20%.

2.28 HGV data for the other roads at the junction, the A382 and the minor road is based on a

midweek day’s manual classified count in May 2004 and automatic traffic count in March

2012. These are goods vehicles (OGV1 and OGV2), buses and articulated vehicles. The

results are shown in Table 2.4.




Table 2.4 – Average Weekday HGV daily flow on non-trunk roads

Location Before FYA % difference

A30 east of jct 4,950 5,250 6%

A30 west of jct 4,500 4,750 6%

A382 west of jct 600 890 49%

Minor rd 110 130 18%

2.29 This shows that:

Although growth in the number of HGVs on the A30 is in line with general traffic growth

on the trunk road, there is much greater growth on the two other roads.

While the numbers on the minor road are still low and the increase may be explained by

the limitations of the one day count before, the A382 results do show clear evidence of

increased HGV traffic using that road to access the A30 at the improved junction.

Journey Time Analysis

2.30 This sub-section examines the evidence on the impact of the scheme on journey times

around the junction. Normally the POPE evaluation of this is based upon observed journey

times before and after the scheme opened. However, for this scheme this has not been done

because:

There were no journey time surveys undertaken as a part of the modelling work for

scheme’s appraisal6.

The scheme was completed under Early Contractor Involvement (ECI) which resulted in

it progressing quickly from entering the orders being made to start of construction.

Unfortunately for the purpose of this study, the speed of progression of the scheme

meant that the opportunity to undertake journey times surveys before the start of online

construction work was missed.

As observed earlier, due to the importance of tourism in the area, the daily traffic flows

on the A30 show a very wide variation seasonally and within the same month. As

congestion is clearly related to traffic flows, it is considered that there would be serious

limitations in using journey time data based solely on moving observer surveys on single

days as being representative of the whole or even most of the year.

Limited journey time data for this part of the A30 is currently available for the period

before 2007.

The nearest TRADS site with any period speed data is a mile west of the scheme which

is too far to be able to detect any impact of the improvements at the junction on any

normal conditions.

Inferred benefits:

A30 through traffic should experience improved journey times through the removal of

congestion at peak times and at all times of day through the removal of the need to slow

down for the manoeuvre around the roundabout rather than drive in a straight line. This

is known as geometric delay and occurs irrespective of whether there are any other

vehicles using the roundabout at the time.

6 There is nothing in either the F&EAR or the Report of Surveys and Local Model Validation Report,




2.31 The POPE evaluation of the impacts on journey times has been based on modelling using

COBA (Cost Benefit Analysis) combined with observed traffic flows. The monetised impacts

of the changes in journey times are detailed in the economy section.

Forecast vs. Outturn Traffic volumes 2.32 Forecast traffic volumes was detailed in the Forecasting and Economic Assessment Report

(T&EAR, November 2004) and the basis of the modelling is detailed in the Report of Surveys

and Local Model Validation Report (June 2004). Forecast of the traffic flows were presented

in detail for the following scenarios and years:

2003 Base Year

2006 Opening Year Do Nothing, low, central and high growth

2006 Opening Year Do Something, low, central and high growth

2021 Design Year Do Nothing, low, central and high growth

2021 Design Year Do Something, low, central and high growth

2.33 Table 2.5 compares the opening year Do Nothing and Do Something forecast traffic volumes

with the observed traffic. As almost all the forecasts were underestimates, only the figures

for high growth (HG) have been shown in this table.

2.34 The Forecasting report states that due to the lack of route choice in the model, future traffic

flows are identical for all roads in the Do Nothing and Do Something scenarios, i.e. it has

been assumed that no reassignment into the corridor or induced traffic will occur.

2.35 Forecast figures for OYA 2008 and FYA 2012 have been proxied based on interpolation

between the 2006 and 2021 forecasts. Flows are shown for traffic in east direction i.e.

eastbound (EB) and westbound (WB).




Table 2.5 – Post opening: Forecasts vs. Observed traffic volumes (AADT)

Location

Do Nothing

(HG) (2006)

Before Flows

Observed(2005) % diff.

One Year After (2008) Five Years After (2012)

Forecast (HG) Observed % diff. Forecast (HG) Observed % diff.

A30 East of jct

WB 11,000 14,700 34% 11,500 14,700 28% 12,300 15,300 24%

EB 13,600 14,100 4% 14,200 14,700 3% 15,500 15,000 -3%

two-way

24,600 28,800 17% 25,700 29,400 14% 27,800 30,200 9%

A30 West of jct

WB 10,400 12,700 22% 10,800 13,200 23% 11,600 13,300 14%

EB 12,700 12,600 1% 13,300 13,100 -1% 14,500 13,300 -8%

two-way

23,100 25,400 10% 24,100 26,300 9% 26,100 26,600 2%

A382 Whiddon Down

N/A N/A N/A 6,700 6,300 -6% 7,200 7,400 3%

Minor rd north of jct

N/A N/A N/A 1,300 1,000 -23% 1,400 1,200 -14%




2.36 The key points regarding the comparison of the forecast flows against the observed data are:

This clearly shows that the appraisal significantly underestimated the traffic levels on the

A30 in the one year after, even in the high growth scenario.

Five years after opening, the low rate of traffic growth in recent years has meant that

traffic levels are closer to the high growth forecasts.

A30 forecast flows shows a noticeable imbalance in the flows split by direction unlike the

observed data which shows that flows are fairly evenly split by direction as would be

expected in this location where the are no local alternative routes of the same standard.

A comparison of the Do Nothing forecasts and the Before traffic volumes shows that the

differences between these volumes are very similar to the differences between Do

Something forecasts and observed traffic volumes. Therefore, the inaccuracy of the

forecasts is due to an inaccurate Base model rather than errors in the way the scheme

itself was modelled.

Traffic on the two local roads is close to the predicted levels.

Why did the forecast underestimate traffic?

2.37 In 2004, when the scheme was appraised, there were no permanent counts in the immediate

area around the scheme, even on the trunk road; the nearest counter on the A30 was near

Exeter Tedburn St Mary, 21km east of the roundabout7. Between that location and

Merrymeet, there is a grade-separated junction with the C50 road known as Woodleigh.

2.38 To develop the model for the Merrymeet scheme, 12 hour manual classified counts (MCC)

were undertaken at the roundabout and the junctions in Whiddon Down village between 2002

and 2004. The data from the permanent count at Tedburn was used to develop conversion

factors for the MCC data.

2.39 An analysis of how the MCC data was used to create the forecast suggests the following

weaknesses:

Count data from 12 hours on single Wednesday in May 2004 was the basis for

calculating the A30 flows through the junction. As shown in Figure 2.3, this road has a

very seasonal pattern of traffic strongly indicating to the significance of tourism to traffic

flows on the A30. It could easily be the case that the selected day was untypical and 12

hours was insufficient to adequately model 24 hours flows. This is judged to be the more

likely explanation for the underestimation;

The calculated base year (2003) AADT east of Merrymeet used in the model is 21,829

compared to the observed AADT of 28,189 at Tedburn. The main reason for considering

this to be unlikely is that this would require over 6,000 vehicles accessing/egressing the

A30 from the minor roads at Woodleigh junction and Fingle Glen.

The base flows used in the model have northbound flows as 18% lower than southbound

whereas the observed data shows that the difference is less than 1% which is what

would be expected given the lack of alternative long-distance routes along the corridor.

This discrepancy could indicate the limitation of using only 12 hour flows or possibly a

weakness in the data collection and processing. Examination of the data suggests that

the figures for southbound traffic west of the junction and northbound traffic east of the

junction could have mixed up during data processing.

7 The TRADS site used is 608 and named as Tedburn St Mary, although it is not close to that village.




2.40 It is worth noting that although the traffic forecasting report and scheme modelled only

concerns the annual average daily traffic based on the May survey, that data was also

collected for a day in August for use in the Environment Statement, as shown in the

Environment evaluation in section 5. In the case of the August data, it seems that the

opening year daily traffic was accurate.

2.41 The 12h MCC data from May was converted to a 24 hour annual figures using DMRB

methodology to create factors based on permanent data from the Tedburn site8. The nature

of the seasonality of traffic flows on the A30 at Whiddon down junction as shown earlier,

means that there may have been a problem with the seasonality factoring, but checks against

2008 data shows that the factoring used is still valid9.

Reliability - route stress

2.42 The AST stated that driver stress would remain at 28% in the do minimum and do something

scenarios. The basis for this is unclear. Route stress is a metric defined in the standard

guidance in DMRB which provides a proxy measurement for reliability and is in the range

75% to 125% where 75% is the lowest possible measurement.

2.43 Removal of the roundabout will have reduced the geometric delay and congestion delay at

peak times for the through traffic which forms the majority of vehicles at this location. This

has improved A30 reliability, particularly in the peak periods in the year.

2.44 Traffic making right turns on or off the A30 and traffic crossing over the A30 will also benefit

from improved reliability in peak periods.

8 DMRB gives: Seasonality Index = Average August 2003 Weekday 24-Hour Flow

Average Neutral Month 2003 Weekday 24-Hour Flow 9 In the case of this case of this scheme appraisal, the neutral months were considered to be April, May,

June, September and October.




Key findings from section 2: Traffic

Traffic volumes

Since 2008, the A30 has shown traffic growth, unlike the wider trends which have seen

traffic in Devon and on rural A roads nationally having fallen year-on-year since 2007.

There is a clear underlying trend of traffic growth on the A30 both sides of this junction.

On weekdays 32,700 vehicles pass this junction, an increase of 6% since 2005.

On the A382 which approaches the junction from Whiddon Down village there has

been an increase of over 1,000 vehicles per day which reflects the improved access to

the trunk road network now provided at this junction. This also includes an increase in

HGV numbers of nearly 50%.

Turning counts show that around three-quarters of traffic passing this junction is A30

through traffic which benefits from no longer needing to give way at the roundabout

and can pass through the junction without needing to slow or stop.

August traffic volumes are the highest of the whole year, due to the importance of

tourism to the economy of Devon and Cornwall. These have shown no change in 2011

compared with before the scheme was built.

Forecasting

Scheme appraisal significantly underestimated the average traffic levels on the A30 in

the one year after stage, even in the high growth scenario.

Five years after opening, the low rate of traffic growth in recent years compared to the

forecast has meant that A30 traffic levels are now closer to the forecasts.

Although traffic on the A382 which runs though the village is now higher than before

the scheme was built, it is close to the high growth forecast level.

Journey Times

It was not possible to confirm changes in journey times based on observed data.




3. Safety

Introduction

3.1 This section presents an evaluation of how the scheme is performing against the NATA

safety objective. WebTAG states that this objective is:

To reduce the loss of life, injuries and damage to property resulting from transport accidents and crime

3.2 The Safety Objective has two sub-objectives:

To reduce accidents; and

To improve security.

Sources

3.3 The evaluation of the safety impacts in this section is based on the following sources:

Data on Personal injury accidents (also known as collisions)

STATS19 data from the Area 1 MAC.

3.4 The accident data is based on the records of personal injury accidents recorded in the

STATS19 form collected by the police when attending accidents. The accident data referred

to in this report has not necessarily been derived from the nationally validated accident

statistics produced by the DfT. As such, the data may subsequently be found to be

incomplete or contain inaccuracies. The requirement for up-to-date information and site

specific data was a consideration in the decision to use unvalidated data and, as it is sourced

from Local Processing Units, it is sufficiently robust for use in this report.

3.5 As the numbers of accidents here is fairly low, we have also obtained records of damage-only

accidents where the police attended. These are known to represent only a minority of such

accidents, but are of interest in giving further evidence of trends.

Forecasts of the safety impact

COBA models of low and high growth scenarios (2005)

Further investigations

Road Safety Audits for Stages 1, 2, 3 and 4a and b.

Study Area

3.6 The safety impact of the scheme (together with the economic impact) was modelled in the

DfT’s Cost Benefit Appraisal Program (COBA) for a short section of the A30 and a small

network of the roads including the A382 and A3124. This model forecast no changes to the

accident numbers on the non-trunk roads beyond the vicinity of the junction so for this study

we have focussed solely on the A30 and the junction which covers the overwhelming majority

of the traffic movements, and omits the small number of accidents directly within Whiddon

Down, which are most likely to be linked to factors unconnected with the changes to the

junction.




Accident data before construction and after opening

3.7 STATS19 data was obtained for the following periods:

Five years before start of construction: November 2000 – October 2005

Four years and six months after full opening: January 2007 – June 2011

Normally for an FYA study, we would use five full years of data for the post opening period,

but this data was not yet available at the time of this analysis (June 2012).

Accidents and casualty numbers

3.8 These sub-sections analyse the numbers of accidents and casualties in the periods before

and after construction of this scheme. This is based on the STATS19 data. Results here

have also been subjected to statistical significance testing which is detailed in Appendix C,

and the findings are included in the analysis presented here.

3.9 Table 3.1 provides a summary of the number of personal injury accidents within the key

network of roads in the area used in the modelling of the scheme broken down into yearly

periods by severity. Accidents are categorised by the severity of the injury to the worst

casualty resulting from the accident. In the case of this data, no fatal accidents were

recorded.

3.10 As the post opening period is slightly shorter, the savings have been adjusted to allow for

this.




Table 3.1 – Number of Personal Injury Accidents (2km/1.2 mile section centred on Whiddon Down)

Accidents by Severity and 12 month periods

Accident and casualty totals

Category

5 years before

(2000 – 2005)

4.5 years after

(2007 – 2011) 4.5 year saving

total annual total annual total annual

Personal Injury Accidents 26 5.2 20 4.4 3.4 0.8 (15%)

Casualties 38 7.6 30 6.7 4.2 0.9 (12%)

All accidents 60 12.0 34 7.6 20.0 4.4 (37%)

Accident and casualty totals – ignoring first post opening year

Category

5 years before

(2000 – 2005)

3.5 years after

(2008 – 2011) 3.5 year saving

total annual total annual


Casualties 38 7.6 15 4.3 11.6 3.3 (44%)

All accidents 60 12.0 15 4.3 27.0 7.7 (64%)

3.11 The following conclusions can be drawn from the data in Table 3.1.

4.5 years after opening, the numbers of injury accidents and casualties was reduced

compared with the period before (15% and 12%).

The trend in the post opening period is distorted by the first 12 months after opening,

which showed an unusually high level of accidents, compared with the five years before

and the subsequent period in the post opening period. This suggests that a small

minority of drivers were failing to understand the revised road layout. This finding was




also noted in the first post opening Road Safety Audit (RSA stage 3) which identified a

particular concern that some A382 eastbound drivers appeared to be undertaking unsafe

manoeuvres having missed the junction for the A30 to Exeter, as shown later in this

section. Following the audit, road signing changes were implemented to address the

RSA recommendations.

From 2008 onwards, the annual personal injury accident rate has halved since the five

years before, giving an annual saving of 2.6. Casualties show a similar trend.

Only one serious accident and no fatalities were recorded during the before period,

giving an accident severity level of 5%. All injury accidents in the after period were

slight; hence, all that can be concluded regarding the severity of accidents following the

completion of this scheme is that there is no evidence of a particular problem with

accident severity here.

3.12 We have also looked at a narrower section, centred on 250m of the A30 either side of the

junction. The results are summarised in Table 3.2. All injury accidents in this area were

categorised as slight.

Table 3.2 – Number of Personal Injury Accidents (0.5km/0.3 mile section centred on Whiddon Down)

Accident and casualty totals

Category

5 years before

(2000 – 2005)

4.5 years after

(2007 – 2011) 4.5 year saving

total annual total annual total annual


Casualties 31 6.2 9 2.0 18.9 4.2 (68%)

All accidents 46 9.2 13 2.9 28.4 6.3 (69%)

3.13 The following conclusions can be drawn from the data in Table 3.2.

In this area around the junction, there are clear reductions of around two-thirds for injury

accidents and casualties.

Saving for all accidents, including damage only, shows the same trend.

Compared with the reduction in accidents and casualties noted in Table 3.1, there is a

much greater impact at the junction. This is due to the accident cluster which existed at

the former roundabout, as shown in the following sub-section.

Locations of accidents within scheme area

3.14 Figure 3.1 shows the locations and severity of the accidents on the section of the A30 and

junction as tabulated in Table 3.1 and Table 3.2. The area indicated by the dashed line is the

0.5km/0.3 mile zone around the junction. It should be noted that a number of accidents

occurred at the same locations, so these maps can only show an indication of the spatial

distribution of accidents.




Figure 3.1 – Locations of Personal Injury Accidents 2km/1.2miles and 0.5km/0.3miles around junction




3.15 The key points shown by these maps is:

The before period showed a clear cluster of accidents at the roundabout.

After completion of the new junction, there were no injury accidents on the overbridge

and only a few at the diverges and merges with the A30. This is a clear improvement

compared with the number recorded at the former roundabout.

On the A30 beyond the area immediately around the junction (0.5km), the maps show

more accidents in the after period than before but no particular clusters. Hence it is likely

to be as a result of the random variation of accidents numbers.

Vulnerable User casualties

3.16 There are few pedestrians, cyclists, and equestrians users of this junction. The collision data

recorded no casualties who were any of these classes of user in either the before or after

time periods.

Further Accident Analysis

Accident Rate Analysis

Accident Rate for A30 improved by scheme compared to National Average

3.17 The number of accidents along a length of road together with its AADT (Annual Average

Daily Traffic) can be used to calculate an accident rate, known as PIA/mvkm (Personal Injury

Accident per million vehicle kilometres). The purpose of measuring the rate is that:

It allows for a change in traffic flows, which is of particular importance when traffic has

increased significantly over the time period under consideration.

It enables comparison between different sections of the A30.

It enables comparison with national average rates both expected and observed.

3.18 Table 3.3 shows the accident rates calculated for the sections of A30 before and after the

scheme, based on average AADTs on the sections over the time periods concerned. The

national average is for an older two-lane dual carriageway, based on data used in COBA is

also shown for the years 2001 and 2009, representing the mid-point years of the before and

after periods. Woodleigh is included here as a control site, as it is a similar standard of road

through a rural area.




Table 3.3 – Accident Rate Five Years Before and After compared to National Average

Section

Period

before:’00-‘05

after:’07-‘11

Length (km)

total PIA Accident

Rate (PIA/mvkm)

2km around Whiddon Down Before

2

26 0.269

After 20 0.218

After (3.5 yrs) 9 0.098

0.5km around Whiddon Down Before 0.5

21 0.869

After 7 0.305

Control area

A30 Woodleigh junction (2km)

Before 2

7 0.068

After 5 0.052

Expected National Average PIA/mvkm for modern dual carriageway no hardshoulder

1

2003 0.160

2009 0.136

Observed national average for rural A roads

2

2009 0.202

1 Based on DMRB Vol 13, Section 1, Part 2, Chapter 4, Table 4/1 ‘link and junction combined’ modern means post 1980

2 Based on DfT data for GB at data.gov.uk/dataset/road-accidents-safety-data/

3.19 The key points to note from Table 3.3 are:

The accident rate on the A30 around Whiddon Down reduced after the completion of this

scheme, and this is most evident in years 2 to 5.

In the narrow area focussed on the junction, the before accident rate was high due to the

roundabout and has dropped by two-thirds in the post opening period.

Compared with the national average, the A30 around the junction has an accident rate

that is now largely as expected, and is clearly better than the worse than normal rate

seen before the scheme was built.

Statistical Analysis

3.20 Appendix C details the statistical tests on the accident and casualty data. The key results

are:

Within 0.5km of the junction there is a statistically significant reduction in numbers of

injury accidents and casualties compared to the period before.

Comparing this section of the A30 including the roundabout with a section of the A30

where there was no junction improvement, there was a greater reduction in accident

numbers over the same period, but this is not statistically significant.

Road Safety Audits

3.21 Post opening road safety audits were undertaken for Stages 3, 4a and 4b (12 months and 36

months after opening).

3.22 The initial post opening study identified the following problems:

Evidence of vehicles overshooting at the end of both A30 diverges.




Some A382 eastbound drivers undertaking unsafe manoeuvres, having missed the

junction for the A30 to Exeter (i.e. eastbound traffic) which uses the overbridge.

3.23 The implementation of remedial signing schemes was recommended in the RSA Stage 3 and

these had been carried out by the time of the Stage 4a and b audits.

3.24 The Stage 4a 12 months after report stated that the collision data suggested that users had

familiarised themselves with the new junction layout but at that time it was too early to make

firm conclusions.

3.25 Three years after opening, the 36 month audit (Stage 4b) found that although there was

some evidence of vehicles colliding with the kerbline, the collision data showed a significant

reduction in accidents with none having occurred at the junction in two years. It concluded

that:

Due to the significant reduction in collisions and the fact that none have occurred in the final two year period of this review, it is recommended that no further monitoring is required at this junction. If further collision problems arise in the future this would appear as a cluster site in the yearly review of collision data.

Forecast vs. Observed Accident Saving

3.26 Details of the modelling for the accident saving is contained within the COBA model produced

for the economic appraisal. The model covered the A30 and a small network of roads and it

predicted both the economic impact of the accident savings and the underlying forecasts of

the numbers of accidents and casualties both with and without the scheme in the opening

year, design year and over the whole appraisal period under forecasts of high and low growth

of both traffic and the economy.

3.27 COBA produces forecasts of the annual savings of accidents in the opening year and the

design year, the 15th year after opening. As shown in Table 3.4, the midpoint between the

low and high growth savings forecasts for these two years is very close, and there is also little

change between the opening year and design year savings. Hence the midpoint provides a

valid annual forecast to compare with the observed average annual saving in the first five

years.

Table 3.4 – Forecast Personal Injury Accident savings

Period Category Low growth High growth Mid-point

2007 (forecast opening year)

Links 0.3 0.3 4.0

Junctions 3.6 3.7

2021 (forecast design year)

Links 0.0 0.0 4.4

Junctions 3.9 4.8

60 years All 243 (including 18

fatalities) 287 (including 21

fatalities) 265

3.28 From Table 3.4, we take the expected saving in the first five years to be 4.2 annually. This is

compared with observed savings in Table 3.5.




Table 3.5 – Forecast vs. Outturn Accident savings

Source Definition Period Annual saving

Forecast Modelled area Average midpoint saving for first 5 years

4.2

Observed

Junction and 2km section

Opening year -5.8

First 4.5 years 0.8

3.5 years after opening year

2.6

Junction and 0.5km section of A30

4.5 years 2.6

3.29 This comparison of the accuracy of the forecasts shows:

In the opening year, the spike in the number of accidents, as shown in Table 3.1, means

that at the OYA stage there was a negative impact.

Now with nearly five years of post-opening data, we can see positive benefits in terms of

accident savings are evident from the second year onwards, and when considering the

area immediately closest to the junction, although this saving is still 34% less than

expected.

As there were no fatalities and only a single serious accident in the time period analysed,

the observed data since late 2000 suggests that the forecast of the numbers of fatalities

saved by this scheme was incorrect.

Further investigation of forecasting

Numbers of PIAs

3.30 Accident benefits (and disbenefits) are modelled in detail by link and node. An examination

of the model’s detailed results showed all the benefits were from the removal of the

roundabout node. The small disbenefits from the new overbridge and associated links and

nodes were clearly outweighed by the removal the roundabout and former approach links.

3.31 As the model forecast the same traffic levels in both the Do Minimum and Do Something

scenarios, we would not expect any changes in the wider area.

3.32 Hence the most meaningful comparison of before accidents with observed saving at five

years after is based on the short section of 0.5km centred around the junction which captures

the majority of the modelled impacts. Our observed finding of 2.6 accidents saved compared

with a forecast of 4.2 shows at the FYA stage shows that the safety impact is one-third lower

than forecast.

Severity

3.33 Safety modelling in COBA used observed accident rates numbers, as is the usual approach.

Unusually, it also took into account atypically high levels of fatal and serious accidents. This

was based on observed data for the five years prior to the appraisal. The Scheme

Assessment Report noted that Personal Injury Accident data for the period 1998 to 2002

showed 20 accidents in the vicinity of the roundabout of which 10% were fatal, while the

Report of Surveys and LMVR showed the data on which the modelling was based on

included 3 fatalities which occurred in 1998 on the A30, two of which were at the roundabout.

On this basis, the modelling included non-default levels casualties per accident at the

roundabout in the Do Minimum scenario. These were:




9.5% of personal injury accidents at the roundabout in the Do Minimum, including a

fatality instead of default of 0.6% for a junction of this type on a dual carriageway.

Similarly the rate of seriously-injured casualties at the roundabout was set to 14%,

instead of the default 10%.

3.34 Now clearly fatal and serious accidents only form a minority of the injury accidents so

extrapolation of long-term impacts based on a small quantity of data is less certain than for all

accidents, but the data from the period late 2000-2005 does raise concerns about the validity

of the assumptions used in the model. The modelling has a severity rating (i.e. fatal and

serious accidents) of nearly 25%, while five years of observed data (as shown in Table 3.1)

showed only no fatalities and one serious accident, which occurred some distance from the

roundabout, giving a severity rating of 4%. Looking at the accidents recorded at the

roundabout only, and using the data from the Report of Surveys and LMVR, gives two

fatalities in 8 years from 1998 to 2005.

3.35 Although we cannot know how many fatal and serious accidents would have occurred at the

roundabout had the scheme not been built, the observed data for the period 2000-2005 does

not show the same problem with fatalities as the data from the late 1990s. This suggests that

modelling of the roundabout over-estimated the accident fatality rate and hence the saving

following its removal.

Security 3.36 This scheme was not predicted to have much impact on the NATA security sub-objective.

Most of the indicators for security which apply to highways schemes do not apply to this

scheme which is in a rural area. One lay-by was closed, but other facilities for road users

remain.

3.37 No change to any aspect of security has changed since the OYA study, hence our

assessment at FYA remains neutral, as forecast.




Key findings from section 3: Safety

Accident numbers

In the first year after the completion of the scheme, there was an increase in accidents

compared with the before period. This was noted in the OYA and in a post opening

Road Safety Audit which suggested that users were experiencing problems with the

new layout. Some improvements were made to road signing and in the subsequent

period from 2008 onwards there was an annual saving of 2.6 injury accidents and 3.3

casualties, thus showing a successful long-term trend of fewer accidents.

Mapping of the accidents shows a cluster at roundabout before the scheme was built.

Accidents on the 0.3 mile / 0.5km short section of the A30 and the junction reduced by

63%, representing a saving of nearly 12 accidents in 4.5 years.

There were no fatalities and a single serious accident in the before period.

No pedestrians or cyclists were injured before or after.

Forecasts

The removal of the roundabout was forecast to be the source of all the safety benefits

of this scheme, as the replacement overbridge and associated links would have much

lower accident rates.

Observed saving at the roundabout is 34% lower than predicted.

Forecasts of fatalities saved through the removal of roundabout were too high, being

based on observations in the late 1990s, which do not correlate with observations in

the early 2000s. Later data from before the scheme was built indicates that although

there were a high number of accidents, there was not an unusual severity problem.

Road Safety Audits

Road Safety Audits identified problems when the scheme first opened but have noted

that these seem to have been related to road users’ unfamiliarity with the new layout

and concluded at 36 months after opening that there was a significant reduction in

collisions in the final two years.

Security

No impact on security, as expected.




4. Economy

Introduction

4.1 This section presents an evaluation of how the scheme is performing against the NATA

economy objective, which is defined in WebTAG as:

To support sustainable economic activity and get good value for money

4.2 The five sub-objectives are to:

Get good value for money in relation to impacts on public accounts;

Improve transport economic efficiency for business users and transport providers;

Improve transport economic efficiency for consumer users;

Improve reliability; and

Provide beneficial wider economic impacts.

4.3 When a scheme is appraised, an economic assessment is used to determine the scheme’s

value for money. This assessment is based on an estimation of costs and benefits from

different sources:

Transport Economic Efficiency (TEE) benefits (savings related to travel times, vehicle

operating costs and user charges);

Accident costs (savings related to numbers and severity level of accidents); and

Costs to users due to construction and maintenance.

4.4 This section provides a comparison between the outturn costs and benefits and the forecast

economic impact, as well as evaluating reliability and the scheme’s wider economic impacts.

Sources

4.5 The sources of the economic impacts used in this study were obtained from:

A30 Merrymeet Junction Improvement, Forecasting and Economic Assessment Report

(F&EAR), November 2004;

COBA models, Sept 2005;

Outturn costs from the HA finance manager, October 2011; and

AST.

4.6 The economic basis of the benefits in the F&EAR was based on a 60 year appraisal period in

line with the latest guidance. This superseded the 30 year forecasts presented in the

Scheme Assessment Report, (January 2003).

4.7 All the monetary benefit modelling for this scheme was undertaken using Cost Benefit

Analysis (COBA) software.

4.8 Modelling was undertaken for low and high growth scenarios. The differences between low

and high growth results were proportionally quite low and as observed traffic has been above

the high growth forecast, as noted in the traffic section of this report, in this economic

evaluation we have focussed on the high growth forecasts.

4.9 COBA (Cost Benefit Appraisal) was used for the economic analysis of this assessment.

COBA performs a fixed-matrix appraisal and hence assumes that no additional traffic is




induced by the scheme. This assumption was consistent with the conclusions drawn from

the Induced Traffic Assessment, which stated that due to the limited nature of alternatives to

road transport on the A30 and the location of the site away from major urban areas, there

would be little impact due to induced traffic.

Scheme costs

Introduction

4.10 This section compares the forecast cost of the scheme with the outturn costs. The forecast is

based on the cost given in the T&EAR (November 2004) and the outturn spend profiles for

the scheme was obtained from the HA finance manager in October 2011.

Present Value Costs

4.11 Cost benefit analysis of a major scheme requires the costs to be considered for the whole of

the appraisal period and they need to be expressed on a like-for-like basis with the benefits.

This basis is termed Present Value. Present Value is the value today of an amount of money

in the future. In cost-benefit analysis, values in differing years are converted to a standard

base year by the process of discounting giving a present value10

.

4.12 The forecast Present Value Costs (PVC) for this scheme includes the following types of costs

incurred over the appraisal period, expressed in present value terms:

Investment Costs;

Operating costs; and

Indirect Tax revenue.

Investment Costs

4.13 The investment cost is the cost to the Highways Agency of constructing the scheme and

purchasing the land. As with the approach taken for the OYA study, in this FYA POPE study

we have taken the forecast investment cost from the T&EAR of November 2004. That

document gave the costs at programme entry in 2001 prices.

4.14 Prior to the start of construction, the forecast cost was increased to £8.8m and this figure was

used in the final COBA modelling.

4.15 The forecast and outturn costs are summarised in Table 4.1. For consistency with other

POPE studies we have converted all to 2002 prices.

Table 4.1 – Investment costs

£m, 2002 prices Forecast cost (T&EAR) Outturn cost

(as of Oct 2011)

Investment cost 7.6 10.8

4.16 The key point regarding scheme cost as shown in the table is that the outturn cost was 42%

higher than forecast.

10 Discounting is defined by the Treasury Green Book and under current guidance uses a discount rate of

3.5% for the first 30 years.




4.17 The increased cost was identified prior to construction when this scheme was subject to a

cost challenge workshop in 2004. That identified that the 5% Optimism Bias had been

applied to the original Scheme Brief. However, an addition of 15% would have been

appropriate at the early stage the scheme had reached when it entered the TPI (precursor to

the Major Schemes Programme).

4.18 Since this scheme was appraised in the early part of the last decade, HA procedures for

scheme implementation including cost control measures have been significantly altered

through the introduction of the Project Control Framework.

Indirect Tax

4.19 Indirect tax revenue is the expected change in indirect tax revenue to the Government due to

changes in the transport sector as a result of the scheme over the appraisal period. For the

highways scheme in this study, the tax impact is derived primarily from the monetisation of

forecast of the changes in fuel consumption over the 60 years period. A scheme may result

in changed fuel consumption due to:

Changes in speeds resulting in greater or lesser fuel efficiency for the same trips;

Changes in distance travelled; or

Increased road use through induced traffic or the reduction of trip suppression.

4.20 For this scheme, the indirect taxation assessment was forecast together with the benefits

using the COBA model. The POPE approach in evaluating this impact has been based on

using COBA similar to that adopted for journey time benefits later in this section. Table 4.2

shows the forecast of the net change indirect tax based on 60 years.

Table 4.2 – Indirect tax impact

£m, 2002 prices and values Forecast (high

growth, HG) FYA Outturn

reforecast

Net increase in indirect tax revenue over 60 years

£1.18m £0.90m

4.21 The forecasts showed that indirect tax was predicted to increase as a result of the scheme

and the outturn reforecast gives a similar but slightly lower impact.

Present Value

4.22 The overall calculations for the costs to public accounts expressed as present value costs

(PVC) is summarised in Table 4.3.

4.23 The expected increase in indirect tax revenue reduces the cost of the scheme to the public

accounts. At the time this scheme was appraised, the present value cost figure included the

indirect tax impact within the costs figure11

. In the case of this scheme, this approach means

that the cost to public accounts is reduced.

11 Treatment of indirect tax as part of the benefits rather than costs became the official guidance in April

2011.




Table 4.3 – Present Value Costs

£m, 2002 prices discounted to 2002 Forecast Outturn

Investment cost (i.e. PVC based on costs to the Highways Agency (no indirect tax impact)

£8.6m £9.5m

Indirect Tax (additional tax raised for public accounts) -£1.2m -£0.9m

PVC £7.4m £8.6m

4.24 The purpose of the PVC figure in this economic evaluation is in the calculation of the benefit

costs ratio as shown later in this section.

Benefits 4.25 The monetary benefits of the scheme were assessed in accord with the latest guidance on

assessment methodology for capital projects. The benefits were assessed for a 60 year

period and expressed in terms of present value with a 3.5% discount rate. This use of

discounting of monetary benefits over a long period gives Present Value Benefits (PVB),

which can be compared with the Present Value Costs in cost benefit analysis.

4.26 The appraisal of this scheme considered the PVB of the following impacts:

Time and vehicle operating cost benefits; and

Safety benefits (COBA).

4.27 The spread of the forecast benefits are summarised in Figure 4.1.

Figure 4.1 – Forecast benefits

4.28 This shows that the forecast benefits were split almost evenly between journey times and

safety and that consistent benefits were expected to be seen over the long-term.

Time and vehicle operating cost benefits (Transport

Economic Efficiency)

Forecast of Transport Economic Efficiency benefits

4.29 Transport Economic Efficiency (TEE) i.e. journey time savings and vehicle operating costs

(VOC) were appraised using COBA.




Journey Times

4.30 When evaluating the post opening benefits in POPE, we normally use observed changes in

journey times on a comparable basis with the forecast to determine the outturn benefits.

However, in the case of this scheme, this approach has not been possible for the following

reasons:

Modelling showed that more than 99% of the journey time benefits were from the

removal of junction delays at the roundabout. The impact on the links was negligible.

As noted in the traffic section, there is no observed data on the journey times

experienced by traffic using the roundabout before the construction of this scheme, so it

is not possible to make comparisons between the congested conditions at the

roundabout with journey times in the post opening period12

.

4.31 Thus, as with the OYA evaluation, we have derived the outturn benefits by using the original

COBA model combined with observed traffic flow data for the A30 and all the links

immediately around the junction layout, old and new.

4.32 As noted earlier, the A30 here shows very seasonal patterns of traffic flow, thus it was

important to validate the approach used in the COBA model. The seasonality index used in

the modelling was 1.25, which is above the default for this type of road. The model was

based on seasonality in 2003 on the A30, as described in the LMVR. We have checked this

against the 2011 seasonality i.e. comparing August with the traffic neutral months and

confirmed it remains valid, thus have used this in the reruns of COBA.

4.33 Table 4.4 shows the 60 year benefits of the scheme for Transport Economic Efficiency as

originally forecast against the re-evaluation of these benefits at the one and five years after

stages (OYA and FYA). The original appraisal included both low and high growth versions,

but as shown previously that the observed traffic is higher than was modelled, only the high

growth model results are shown here.

Table 4.4 – 60 year Economic Benefits (£m, 2002 prices, discounted)

Transport Economic Efficiency (TEE)

User Category Forecast

POPE Re-forecast based on observed outturn flows

OYA FYA

Travel time Consumer £14.9m £17.0m £14.3m

Business £10.9 £16.8m £14.1m

Vehicle operating costs

Consumer -£1.4m -£0.2m £-0.5m

Business -£0.8m -£0.2m £-0.6m

Total £23.6m £33.3m £27.3m

4.34 This shows that:

At FYA, the scheme delivers substantial travel time benefits for consumer and business

users. There is a slight disbenefit in terms of vehicle operating costs; this is due to a

small increase in fuel used.

12 In recent years it has become possible to analyse before and after journey times around a junction such

as this using sat-nav data, but we are not able to take this approach here because the before period, predates the availability of such data.




Total TEE benefits are higher than forecast, because the traffic flows are higher than

forecast. The reduced assessment at FYA compared with OYA is due to the low traffic

growth observed in that time

Accident benefit modelling

4.35 For the purpose of assessing the economic impacts of road schemes, changes in safety as

measured by changes in accident numbers and severity are monetised. Forecasts are

generated using the methods and accident rates contained in the COBA Manual (DMRB

Volume 13, Section 1) and embodied in the computer program COBA.

4.36 The original COBA model used a non default setting for the accident severity on the A30 and

at the roundabout, based on observed data in 1998. At that time, there had been an

abnormally high severity rate in the area around the existing roundabout. In monetised

terms, reducing the numbers of fatalities and seriously-injured casualties has a greater

economic benefit hence the modelled severity rating is important.

4.37 As discussed earlier in the Safety section, in subsequent years the severity rate was much

reduced. Table 4.5 summarises the assumptions made in the model compared to the

defaults for the link and junction types and the observed data collected for this study covering

the 3 years prior to scheme construction.

Table 4.5 – Casualty severity modelling

Severity

Number and Severity of Casualties per Accident

A30 Whiddon Down roundabout Observed on A30 and

nearby links As modelled (1998)

Default (2000)

As modelled (1998)

Default (2000)

(2000-2005) (2007-2011)

Fatal 0.25 0.0314 0.095 0.006 0 0

Serious 0.5 0.2005 0.143 0.1019 0 0

Slight 0.25 1.312 1.429 1.214 1.476 1.286

%KSI13

75% 15% 14% 8% 0% 0%

4.38 This table shows that the A30 and the roundabout were modelled with considerably higher

severity rates for casualties than is normal for the road type and was observed in the area in

three years before the scheme was constructed.

4.39 For the purpose of the post opening evaluation of the long-term accident benefit, it is

considered that:

The original modelling of accident severity, especially the 75% KSI on the A30 links and

the 9.5% fatalities at the roundabout, was very high and has been contradicted by more

recent data;

It is clearly not reasonable to assume that the observed rate of 0% killed and seriously

injured can be taken as a long-term basis but it does indicate that the long-term trend is

likely to be low.

Therefore, to model the 60 year impacts, the default COBA modelling of severity has

been assumed.

13 %KSI is the proportion of casualties who are killed or seriously injured.




4.40 As for the economic efficiency benefits, the high growth model has been used for the

evaluation here. The results of the COBA modelling for accidents are summarised in Table

4.6.

Table 4.6 – 60 year Safety Benefits

60 Year benefits Original Forecast

(high growth)

Re-forecast from COBA model re-run with observed flows, observed 5 years

before accidents at roundabout and default accident severity rates

OYA FYA

Monetised Safety benefits

(£m 2002 prices discounted at 3.5%) £24.7m £6.9m £7.4m

Forecast accident saving 287 257 266

Forecast casualty saving

21 fatalities

19 seriously injured

443 slightly injured

1 fatality



1 fatality



4.41 The comparison of the original forecasts with the re-forecast of the 60m year safety benefits

based on observed traffic and the assumptions detailed above shows:

60 year safety benefits are now expected to be only a third of the original forecast in

terms of monetary value.

The re-forecast saving of accident numbers is slightly lower than predicted, but the more

important change is in the savings in the numbers of casualties killed or

seriously-injured.

This reduction in the forecast of the numbers of casualties killed or seriously injured in

the accidents saved is the main reason why the monetised value of the accident

reduction over 60 years is only a quarter of that forecasted.

The reduction in the safety benefit is despite there being higher traffic flows observed

than were modelled.

4.42 It is also noted that, as may be expected, virtually all the benefits of this scheme are derived

from the reduction in junction accidents.

Delay during Construction

4.43 The scheme appraisal calculated that delays during construction would have a negative

impact on journey times. Using the QUADRO software, this disbenefit was monetised at

£1.0m for high growth14

. This is low relative to the other costs and benefits and has not been

evaluated in this study. The original figure has been used as a reasonable estimate for the

purpose of overall cost benefit analysis.

Summary of Monetised Benefits

4.44 The benefits forecast and re-forecast based on outturn data as discussed in the previous

sections are summarised in Table 4.7.

14 A30 Merrymeet Junction Improvement, Forecasting and Economic Assessment Report, Table 8




Table 4.7 – Summary of Present Value Benefits

Summary of Benefits

Costs in £m 2002 prices discounted to 2002 at 3.5%

Forecast (high growth)

Re-forecast with observed flows

OYA FYA

TEE £23.6m £33.3m £27.3m

Safety benefit £24.7m £6.9m £7.4m

Delay During Construction -£1.0m -£1.0m -£1.0m

Total Present Value Benefits (PVB) £47.3m £39.3m £33.7m

4.45 The above summary table shows that overall present value benefits (PVB) over 60 years is

now forecast to be £34million, which is 29% below that forecasted. As seen at OYA, the

additional benefits from journey times due to additional traffic are outweighed by the

reduction in the forecast safety benefits.

Benefit Cost Ratio (BCR) 4.46 The benefit-cost ratio (BCR) is an indicator used in the cost-benefit analysis of a road

scheme that attempts to summarize the overall value for money of a project or proposal. The

BCR is the ratio of the benefits of a project or proposal, expressed in monetary terms, relative

to its costs, also expressed in monetary terms. All benefits and costs are expressed in

present values as detailed in the above sub-sections.

4.47 As discussed earlier, the most recent guidance on indirect tax impacts is to include these as

a benefit rather than a reduction in the cost. This means that when a scheme leads to

increased fuel consumption and hence increased tax revenue, the PVB is increased rather

than the PVC being decreased. The impact on the PVB of adding the indirect tax impact is

summarised in Table 4.8.

Table 4.8 – Present Value Benefits with indirect tax impact

Benefits over 60 years (£m) Forecast Outturn reforecast

Present Value Benefits (PVB) £47.3m £33.7m

Indirect Tax impact £1.2m £0.9m

PVB adjusted for indirect tax £48.4m £34.6m

4.48 A comparison of how the costs and benefits have been used to produce the BCR for the

forecasts and the BCR from the POPE evaluation discussed in this section are given in Table

4.9 with the indirect tax treated via the two alternatives. All benefits are over 60 years, post

opening.




Table 4.9 – Benefit Cost Ratio

All monetary figures in 2002 prices and values

Forecast FYA Outturn reforecast

Present Value Benefits (PVB) £47.3m £33.7m

Present Value Costs (PVC) £7.4m £8.6m

BCR = PVB / PVB 6.3 3.9

Indirect tax as benefit

PVB £48.4m £34.6m

PVC £8.6m £9.5m

BCR 5.6 3.6

4.49 The key points regarding the BCR as evaluated at this stage are:

As the benefits are lower than forecast and costs higher, the BCR is lower than forecast.

According to DfT guidance15

, a scheme is classified as high value for money if its BCR

lies between 2.0 and 4.0, which is clearly achieved in this case.

The effect of including the Indirect tax impact in the benefits (an increase) rather than the

costs (a decrease) has only a marginal lowering effect on the overall BCR.

4.50 It should be noted that the BCR ignores non-monetised impacts. In the former NATA

assessment and its replacement, the Transport Business Case, the impacts on wider

objectives must be assessed but are not monetised. The evaluation of the environmental,

accessibility and integration objectives is covered in the following sections.

Wider Economic Impacts

4.51 The AST states that the scheme is not located in a regeneration area and no development

was dependent on the scheme, hence the impact on this sub-objective was neutral. The

junction lies in a rural area directly abutting the Dartmoor National Park and thus is not likely

to be considered a suitable location for development in the future.

4.52 Areas of Cornwall and north Devon are served by the A30 and these are categorised as

regeneration areas. Hence improving access to these areas by reducing journey times for

trunk road traffic through the Whiddon Down junction as provided by the improvement to this

part of the A30 does contribute towards the goals of regeneration.

15 At the time of this study, this is currently under revision.




Key findings from section 4: Economy

Costs and Benefits

The investment cost of the scheme was £10.8m in 2002 prices, which was

substantially higher than the predicted cost of £7.6m when it was appraised in 2004.

This had made insufficient allowance for optimism bias for the stage when it entered

the programme of schemes.

Journey time benefits were higher than expected due traffic levels on the A30 being

higher than forecast, despite the economic downturn.

Safety benefits, which had been expected to comprise half the benefits, were

evaluated to be much lower than expected. This is because the forecasts were based

on the prediction of a continuing long-term problem of a high number of both accidents

and fatalities at the roundabout without the scheme in place. The lower outturn

benefits was based on an observed reduction in accident numbers and the assumption

of a typical rate of fatal and serious accidents at the roundabout had the scheme not

been built.

Outturn Benefit Cost Ratio (BCR) was lower than forecast but at 3.6 still represents

high value for money.

Wider Economic Impact

None to immediate area near the junction which is not a development area, but there

are slight benefits to regeneration areas in Cornwall and north Devon.




5. Environment

Introduction

5.1 This section documents the evaluation of the environmental sub-objectives, focussing on

those aspects not fully evaluated at the OYA stage, or where suggestions were made for

further study.

5.2 When the ES was written, the junction was called Merrymeet and since the OYA evaluation

the name has been changed to Whiddon Down, both names are used in this section as

appropriate.

Summary of OYA Evaluation Recommendations

The OYA evaluation identified a number of areas where further analysis was required at the FYA stage to confirm the longer term impacts of the scheme on the surrounding environment, these are summarised as follows:

Landscape –successful establishment of the landscape planting and seeding would be re-evaluated at the FYA stage.

Biodiversity –monitoring of reptiles and dormice was expected to be carried out and results would be reviewed as part of the FYA report. It was too early to evaluate the success of the methodology for establishment of species rich grassland and ongoing establishment should be evaluated as part of the FYA study.

Heritage – At OYA publication of an article written for the Devon County Archaeological Journal was not confirmed and the site archive had not been presented for permanent storage at the Royal Albert Memorial Museum in Exeter. Devon County Council had not received a copy of the scheme archaeology report.

Physical Fitness – At OYA Devon County Council was concerned about the safety of cyclists using the junction and that there was no signage which would indicate to cyclists that there were alternative quieter long-distance parallel routes available by using the ‘old’ pre-1970s A30.

Journey Ambience – Anecdotally concerns were raised at OYA by people living locally and commuters about what they considered to be poor advance signage of the junction.

5.3 The Environmental Statement (ES) noted that the scheme’s objectives for Environment

included:

To deliver an environmentally acceptable scheme that protects the natural environment.

The scheme would minimise and mitigate the environmental impacts on areas within and

adjacent to the junction, specifically adjoining Dartmoor National Park.

5.4 The scheme would incorporate appropriate mitigation measures to minimise

environmental effects. Key aspects of the scheme aimed at reducing environmental

impacts would include the following:

Avoiding the Dartmoor National Park;

Minimising landtake and effects on farm holdings, providing replacement farm access

tracks where appropriate;

Minimising the effects on nearby properties, providing earth mounds screening and new

planting where appropriate;




Reducing the overall level of street lighting compared with the existing situation;

Incorporating drainage treatment areas to minimise the risk of pollution to surrounding

watercourses;

Minimise disturbance to wildlife and take measures to reduce the effects on protected

species;

Maintaining and improving provision for pedestrians; and

Recycling and reusing material where practicable.

5.5 The following environmental sub-objectives were appraised in the ES and in the AST

according to NATA guidance at that time (2002):

Noise;

Local Air Quality;

Greenhouse Gases;

Landscape;

Heritage;

Biodiversity;

Water Environment;

Physical fitness; and

Journey Ambience

5.6 For each of these environmental sub-objectives, the evaluation in this Section assesses the

environmental impacts predicted in the scheme’s AST (Appraisal Summary Table) and ES

against those observed five years after opening.

5.7 The AST stated that Townscape was not applicable to this scheme and it has therefore been

scoped out of this evaluation.

5.8 In the context of the findings from the OYA evaluation, and using new evidence collected five

years after opening, this section presents:

An evaluation of the ongoing effectiveness of the mitigation measures implemented as

part of the scheme;

An updated summary of key impacts against all of the nine environment WebTAG sub

objectives, with particular focus on assessment of sub-objectives where it was too early

to conclude at the OYA evaluation stage; and

Additional analysis relevant to close out issues or areas for further study, as identified at

the OYA stage to for consideration at the FYA stage.

Methodology

5.9 This section focuses on those aspects not fully evaluated at OYA, or where at OYA,

suggestions were made for further study and also any issues that have arisen since the OYA

evaluation. The detail of the OYA study is not repeated here, and reference should be made

to the OYA report where required, although key points are incorporated into this five years

after (FYA) report where appropriate to provide contextual understanding.

5.10 No new modelling or survey work has been undertaken for this FYA evaluation.




Data Collection

5.11 The following documents have been used for the FYA:

AST (Appraisal Summary Table) for the scheme (Scheme Assessment Report, January

2003 version) ;

A30 Merrymeet Junction Improvement Environmental Statement February 2005 Volume

1 Text, Volume 2 Figures and Non-Technical Summary (NTS);

As-Built Drawings;

A30 Merrymeet Junction Improvement Maintenance Manual and Appendices;

A30 Merrymeet Dormouse Monitoring 2011 and 2012 Final Report (May 2012);

A30 Merrymeet Reptile Mitigation Monitoring 2011 and 2012 Final Report (May 2012);

The A30 Merrymeet Junction Improvement Archaeological Assessment Report July

2006;

A30 Whiddon Down Junction Improvement Handover Site Inspection Record 29.9.11;

and

A30 Whiddon Down Junction Improvement Handover Environmental Management Plan

(HEMP) November 2011.

5.12 A full list of the background information requested and received to help with the compilation

of this report is included in Appendix D.1.

Site Visit

5.13 As part of the FYA evaluation, a site visit was undertaken in May 2012. This included the

taking of photographs to provide comparison with material produced at the appraisal stage

and at OYA (see Appendix D.2).

Consultations

5.14 Two statutory environmental organisations (Natural England and the Environment Agency),

Devon County Council and West Devon Borough Council, the Dartmoor National Park

Authority and the Parish Council were contacted as part of the FYA evaluation regarding their

views on the impacts they perceive the scheme has had on the environment. The responses

received are summarised in Table 5.1.

Table 5.1 – Summary of Environmental Consultation Responses

Organisation Field of Interest

Comments at OYA Comments at FYA

Natural England (NE)

Landscape & Biodiversity

Commented on Badger licence. Unable to provide any other comments as NE had no after opening monitoring data on which to base a response

Would possibly be able to comment on Dormouse monitoring but required the details of when and how the report was forwarded to NE to be able to locate it in their system.

English Heritage Heritage Unable to comment as no designated sites affected and suggested contacting the local authority

Not re-contacted

Environment Agency (EA)

Water Not aware of any problems – as expected

Again stated that it was not aware of any problems.




Organisation Field of Interest

Comments at OYA Comments at FYA

Devon County Council (DCC)

General PROW (concerned about safety of cyclists, disappointed that no signage directing cyclists to quieter long distance routes)

Drainage (not aware of any problems)

Biodiversity (hedge-banks as expected, no major habitat loss, scheme seems to be

establishing satisfactorily)

Landscape (works blend into local environment and this will improve as planting matures, improvement in light pollution, successful enhancement of local environment)

Heritage (not been provided with a copy of the archaeological report and is therefore not in a position to comment on the impact of the scheme on archaeology and Historic Landscape at this time)

Heritage - DCC records show that a copy of the archaeological report has been provided. Suggested contacting the Archaeological consultant to close out other issues.

General – not aware of any outstanding general environmental issues. Handover of ongoing responsibility for landscape areas to DCC expected to take place June 2012.

Countryside Team provided a response on the slow development of species rich grasslands and potential for gorse to colonise unless treated.

PROW – Whiddon Down interchange is one of the options DCC are considering for managing the Cycle West route from Exeter to Okehampton.

The Road Safety Audit team considered the scheme safe, convenient and comfortable due to its open landscaping

West Devon Borough Council

General Air Quality (beneficial)

Noise (not aware of any issues)

Local signage

Landscape (pleased with extent and type of planting)

Confirmed that local air quality remains good and it is not aware of any complaints relating to noise due to traffic.

Dartmoor National Park Authority

Dartmoor National Park

(DNP)

Junction works avoided any physical encroachment into DNP, planting should in time help assimilate junction into the landscape and lighting is a marked improvement and reduces impact on DNP.

No issues raised since OYA and no further comments to add.

Drewsteignton Parish Council

General Not consulted with in line with methodology at the time

No response received.

Archaeological Consultant

Heritage Provided copy of Archaeological Assessment Report

Confirmed that it currently holds the site archive and that the article which has been written will be forwarded for publication in the Devon County Archaeological Journal

5.15 No information relating to Part 1 Claims was included in the OYA report. At FYA the

Highways Agency Part 1 Team has been contacted regarding Part 1 claims and it is

understood that there have been 4 claims, none of which were successful. The reasons for

the claims being made are not known as the District Valuer is no longer available.

5.16 The area’s Managing Agent Contractor (MAC) has provided animal mortality data which is

included in the Biodiversity section of this chapter.




Traffic Forecast Evaluation

5.17 Three of the environmental sub-objectives (noise, local air quality and greenhouse gases) are

directly related to traffic flows. No new noise or air quality surveys are undertaken for POPE

and an assumption is made that the level of traffic and the level of traffic noise and local air

quality are related. Therefore, if the observed level of traffic is as forecast at the appraisal

stage it can be assumed that the traffic noise and local air quality impacts after the opening of

the scheme are as expected.

5.18 The ES noted that the annual average daily traffic (AADT) two-way flow in the ‘base year

2003’ on the A30 Merrymeet roundabout was 21,800 vehicles to the east of the roundabout

and 20,400 to the west. Approximately 10% were HGVs.

5.19 The ES included traffic forecasts which where used as the basis of the AQ assessment. This

gave forecasts of flows for the opening year of 2006 and design year of 2021 for the

following:

Annual average daily traffic (AADT);

August ADT, as this is the busiest month of the year; and

Saturdays in August.

5.20 As the scheme was forecast to have no impact on route choice or result in any induced

traffic, the forecast are identical for the Do Nothing and Do Something scenarios. To assess

the accuracy of the forecasts against observed data for the OYA and FYA studies, we have

created proxy forecasts for the same years using a straight-line interpolation between the

opening and design year forecasts.

5.21 The comparisons between the High Growth (HG) and observed data are shown below in

Table 5.2 and Table 5.3 .

Table 5.2 – Traffic Forecasts used in AQ Assessment vs. Outturn Flows

Location

AADT

One Year After (2008) Five Years After (2012)

Proxy ES HG Forecast

Observed %diff Proxy ES

HG Forecast Observed %diff

A30, East of Jct 25,700 29,400 14% 27,800 30,200 9%

A30, West of jct 24,100 26,300 9% 26,000 26,600 2%

A382 between services & A30

6,700 6,300 -6% 7,200 7,400 3%

Minor rd 1,300 1,000 -23% 1,400 1,200 -14%

Table 5.3 – August Traffic Forecasts used in AQ Assessment vs. Outturn Flows

Location

August Traffic – Five Years After (2012)

August Daily August Saturdays

Proxy ES HG Forecast

Observed %diff Proxy ES

HG Forecast Observed %diff

A30, East of Jct 45,900 40,600 -12% 64,300 52,400 -19%

A30, West of jct 42,900 37,400 -13% 60,200 50,200 -17%




5.22 August traffic flows were overestimated by over 10% when compared to observed. However

August traffic is clearly subject to greater levels of variation from tourism demand. The Met

Office reported that summer 2011 was colder and wetter than average.

5.23 Based on information within the Traffic section of this report HGV numbers (compared to the

situation before the scheme) have increased as follows:

On the A30 by 6%;

On the C50 minor road by 18%; and

On the A382 west of the junction by 49%.

5.24 With regard to traffic speeds, as noted in section 2 of this report, POPE has no information to

enable any pre- and post scheme comparison.

Five Year after Assessment

5.25 Included in this section is a brief summary of statements from the AST, ES and OYA

evaluations (including close out / key issues identified for further reporting at the FYA stage)

which have been included to provide the context for the FYA evaluation.

Noise

5.26 The AST did not assess noise levels as there was expected to be a less than 25% change in

traffic levels as a result of the scheme.

5.27 The ES stated that the scheme would lead to an increase in traffic noise levels at six

receptors within the study area. However, these increases would be below the levels at which

short and long-term changes were perceptible and were therefore considered to be

insignificant.

5.28 The ES also reported that a low noise surface would be used at the junction.

5.29 At the OYA stage it was stated that:

The scheme Maintenance Manual stated that the works carried out in the reshaping of

Narroway Farm Improvement act as a noise barrier to provide environmental benefits to

Whiddon Down village. The manual also stated that the earthworks on the south western

side of the A382 loop provide environmental benefits to the Travelodge site.

The scheme itself had not led to an increase in traffic on the A30, the traffic counts

between 2005 (before the scheme) and 2007 after opening indicated a 4 to 5% increase

in traffic due to normal traffic growth.

Consultation

5.30 West Devon Borough Council confirmed that it is not aware of any complaints or issues

relating to noise due to traffic in the vicinity of the junction.

Evaluation

5.31 There was no requirement for the HA to undertake noise surveys. A low noise surface has

been used at the junction as expected; prior to the junction improvements the carriageway

was a combination of areas of concrete and Hot Rolled Asphalt (HRA), however, the HRA

was replaced with SMATex (Thin Surface Coating System), which is quieter.

5.32 Based on the before scheme and FYA observed traffic data it can be assumed that in line

with POPE methodology noise due to traffic is as expected for the A30 and C50 i.e. the




changes in flow are no more than +25% (increase) or -20% (decrease) than forecast,

including HGVs.

5.33 For the A382 west of the junction overall traffic is 21% greater than expected, however, HGV

numbers have increased by 49% and it is possible therefore that noise due to traffic could be

worse than expected for the 3 properties and Travelodge within 300m of this route. For the

village of Whiddon Down where it was not expected in the ES that any noise impacts would

occur, noise due to traffic is assumed to be worse than expected for properties on the A382

due to the increase in HGV numbers.

Local Air Quality

5.34 The AST did not assess local air quality as there were not expected to be changes in traffic

flows of 10% or more.

5.35 The ES concluded that considering that the local air quality was good and that no significant

changes in traffic conditions were expected as part of the scheme. UK national air quality

objectives would not be breached as a result of the scheme.

5.36 A small increase in total emissions was predicted with the scheme in operation due to the

predicted higher average traffic speeds for the ‘Do Something’ scenario.

5.37 At the OYA stage it was stated that based on no significant changes in observed traffic flows,

it was likely that local air quality impacts were as expected. An EST score was not provided.

Consultation

5.38 West Devon Council confirmed that air quality was very good in its area, and that the closest

monitoring point is in Chagford - too far away to be representative.

Evaluation

5.39 A comparison of the observed before and after traffic volumes shows that there has been no

significant change in traffic flows as a result of the scheme. A comparison of the forecasts

that were made also shows that no change in traffic volume was expected as a result of the

scheme and this forecast appears to be accurate.

5.40 However, there is a significant difference between the forecast and observed traffic volumes.

The traffic model underestimated the traffic volume on many links, by up to 9% on the A30 at

FYA, but this occurred in all scenarios, i.e. it was due to inaccuracies within the Base model

rather than in the way the scheme was modelled.

5.41 In addition, assuming HGVs were forecast to be 10% of AADTs, the A382 was observed to

have over 200 more HGVs than forecast (890 compared with 610).

5.42 There are no properties within 200m of the A30 east of the junction, and only 1 property, Mill

Farm, within 200m of the A382. As traffic flows on the A382 are relatively low (less than

10,000 AADT), it is unlikely that the higher observed traffic and HGVs would cause any

breach in air quality criteria, especially given the rural nature of the area. Air quality is

therefore likely to still be as expected.

Greenhouse Gases

Context

5.43 The AST and the ES Air Quality chapter both gave the same forecast for the net impact of the

scheme on the Greenhouse Gas sub-objective as 416 tonnes Carbon Dioxide emissions.

The AST assessed this as slightly adverse while the ES stated that the effect would be




negligible compared to the total UK emissions from road vehicles hence the impact would be

neutral.

5.44 The ES states that the impact was forecast using the DMRB air quality spreadsheet based on

200metres each side of the junction. The ES states that average speeds on the A30 as

observed in 2003 and in the Do Minimum (DM) scenario are below 100km/h whereas in the

Do Something (DS) scenario they are above 106km/h. At these relatively high speeds,

carbon emissions tend to increase for higher speeds which explains the higher total

emissions predicted for the DS.

FYA Evaluation

5.45 Since this scheme was evaluated, greenhouse gas emissions are now measured in terms of

tonnes of Carbon rather than CO2. Also, the COBA modelling software has been enhanced

and now provides estimates of the carbon impact of the modelled scheme.

5.46 For the purpose of this post opening evaluation, the latest version of COBA16

was used to

calculate carbon emissions for DM and DS scenarios as follows:

to recalculate a forecast of the net change using the original pre-construction scheme

model of the DM and DS; and

to calculate an estimate of the net difference in emissions in the opening year based on

the observed traffic volumes for the DS and the DM (assuming that overall flows and

strategic routing would not have altered if the scheme had not been built).

5.47 The carbon results from the COBA model are detailed in Table 5.4. Additionally the figures

from the ES have been converted from CO2 to carbon are shown. These figures would have

been calculated using the DMRB air quality spreadsheet and probably for a smaller network

of links than that modelled in COBA.

Table 5.4 – Carbon Emissions (tonnes in year)

Scenario ES Forecast Appraisal model re-run

with latest COBA

Model updated with outturn Flows run with latest COBA

Opening year OYA (2008) FYA (2012)

Do Minimum / without scheme (DM)

1,053 1,626 2,090 2,064

Do Something /with scheme (DS)

1,166 1,665 2,093 2,080

Net increase 113 39 3 16

% change 11% 2% 0% 1%

5.48 The key points regarding the greenhouse gases impacts are:

When observed outturn data is added to the COBA model, the DM and DS emissions

are both higher than in the original COBA model but this is due to underestimates of the

A30 traffic regardless of the scheme. This was detailed previously in Chapter 2.

The main finding at OYA was that the net increase in carbon in the opening year which

had been forecast as about 10% as a result of the scheme, was evaluated to be

negligible in proportion to the overall carbon emissions at the junction.

16 COBA v11 R7




At FYA, the impact is also assessed to be a negligible increase.

5.49 The assessments here show that given the available data we evaluate the scheme impact on

greenhouse gas emissions to be neutral, as expected. As with noise and air quality, the

outcome of this evaluation is consistent with the changes in traffic volumes reported

elsewhere in this document.

Landscape

5.50 The A30 at the location of the junction was already within a deep cutting. The AST stated that

there would be some loss of established highway planting but some attenuation of the notch

effect of the A30 cutting seen from the North West. New planting, reduced lighting and the

new bridge would redress the balance. A neutral impact was assessed overall.

5.51 The ES stated that the design of the scheme aimed to integrate the improved junction into the

landscape as far as possible. It would avoid encroaching into the neighbouring Dartmoor

National Park, but would encroach further into the Tedburn St Mary part of the Area of Great

Landscape Value to the north. Redundant lengths of road would be landscaped. There would

be some loss of existing hedge banks and more recent tree and shrub planting on highway

land. This would be mitigated by new planting.

5.52 Visual impacts would be limited to a few properties. It was seen as an advantage that the

new bridge would span a deep cutting, thereby minimising the need for embankments on the

approach roads. The layout would minimise visual impact.

5.53 On completion of the scheme it was expected that the visual impact of the new junction and

its traffic would progressively diminish as the new tree planting became established. Removal

of lighting columns associated with the existing roundabout would reduce the impact at dusk

and night time at this Gateway to the Dartmoor National Park.

5.54 Some changes to the landscape scheme with regard to the successful integration of surplus

material were discussed at OYA.

5.55 The OYA report stated that:

Planting appeared to be establishing satisfactorily apart from some of the light standard

trees scattered through the plots.

Some spreading shrubs had been planted in too narrow shelters and were developing a

‘lollipop’ form. This was being addressed with wider shelters being provided by winter

2008.

As expected the overbridge did appear to close the ‘notch’ in the A30 cutting when

viewed from a distance.

The earthworks and ground modelling had successfully reduced views of traffic using the

new overbridge as predicted, and also blocked the headlights of vehicles crossing the

bridge towards the Travelodge hotel. Visual impacts were considered to be as expected

for footpaths, the service area and residential properties.

Impacts on Dartmoor National Park had been minimised e.g. retention of existing

planting, new planting and by significant reduction in lighting.

5.56 Based on the information available it was assumed that the impacts on the landscape

sub-objective were as expected.

Consultation

5.57 Devon County Council confirmed at FYA that the scheme was considered to be establishing

satisfactorily. Some shrub plots with intermittent trees will be handed over to DCC for ongoing




management from June 2012. At the pre-handover site meeting in September 2011 it was

expected that all tree and shrub guards in plots to be handed over to DCC would be removed

before handover.

5.58 The Dartmoor National Park Authority had no new comments to make since OYA.

Evaluation

5.59 A Handover Environmental Management Plan (HEMP) has been issued. This confirms that:

Landscape maintenance operations have been carried out during the 5 year maintenance

period, including grass cutting, removal of gorse, weed control in hedges and around

individual trees and shrubs and noxious weed control.

A joint site meeting held in September 2011 between HA, Devon CC, MAC,

Environmental Co-ordinator and Contractor concluded that subject to appropriate

maintenance being carried out and any defects dealt with between then and June 2012,

there were no significant defects which would prevent transfer of responsibility to any

party in June 2012.

5.60 The HEMP includes strategies for regular maintenance of environmental areas in the future

on a plot by plot basis.

5.61 Based on the FYA site visit planting, including the larger trees (light feathered), is generally

establishing satisfactorily and it would appear that plots have been well maintained during the

aftercare period see Figure 5.1 below. As would be expected there is some variation in

growth depending on species, but subject to ongoing development, planting should fulfil its

longer term screening and integration functions by the design year 2021.

Figure 5.1 – Illustrating generally satisfactory plant establishment, weed free circles and grassland

free from noxious weeds

5.62 Individual shelters were still in place at the FYA site visit in May and as noted at OYA some

plants have developed a ‘lollipop’ form due to the use of narrow width shelters and their

shape would benefit from removal of the shelters. However, it is understood from the

Handover Site Inspection Record that it has been agreed with HA that shelters should remain

in place in the plots to be maintained by the MAC until plants are at least 1.2m tall due to

problems with browsing by animals Figure 5.2 and Figure 5.3 below illustrate narrow

shelters restricting growth at OYA and the situation at FYA. Devon CC had also expected that

all the tree and shrub shelters on the plots they were taking over to have been removed prior

to handover.




Figure 5.2 – (left) Plants developing ‘lollipop’ form in narrow shelters at OYA

Figure 5.3 – (right) At FYA plants will not be able to develop a more natural shape until shelters are

removed

5.63 Nighttime lighting at the junction was considered by consultees at OYA to have been

successfully reduced by the scheme changes. Figure 5.4 and Figure 5.5 below compare the

night time impact at FYA as seen on the A382 approaching the junction, to the ‘before’

situation as illustrated in the NTS to the ES and it is considered that beneficial impacts are as

expected.

Figure 5.4 – (left) Existing night time lighting before the improvement works at the junction

Figure 5.5 – (right) At FYA

Biodiversity

5.64 The AST stated that some species rich Devon hedgebanks would be partially lost, together

with some areas of species rich grassland, although both would be largely mitigated by new

planting. Some minor impact is likely on habitats for reptiles, badgers, Dormice and breeding

birds, although these would be largely mitigated within the scheme design. The impact was

assessed as slight adverse overall.

5.65 The ES noted that the scheme would not affect any designated sites. There would, however,

be some effects on habitats and species.

5.66 The scheme would result in some loss of parts of some of the Devon hedge-banks, although

scheme design minimised this loss and ensured the retention of the better quality lengths.

Reuse of the removed material in new hedgerow planting would provide some mitigation for

the loss. Other vegetation losses, such as grassland, scrub and tree cover would be

mitigated by areas of seeding and planting using native species.




5.67 Measures would be taken to reduce the effects of the scheme on protected species including

badger, dormouse, birds and reptiles. This would include, for example, the capture and

relocation of some species before construction commenced.

5.68 The OYA report concluded that new and replacement habitats had been created within the

highway boundary as expected. It was too early to evaluate the success of the methodology

for establishment of species rich grassland and ongoing establishment should be evaluated

as part of the FYA study. It was noted that gorse had seeded in a few areas, which can be

problematic if allowed to colonise. Clover was present in the verges and central reserve

which was not specified in the Devon CC mix.

5.69 With regard to protected species the OYA report stated that:

Dormice - clearance of habitat was undertaken in accordance with the agreed method

statement. From the monitoring information at OYA it appeared that Dormice were still

present in habitat around the junction. Further monitoring was expected and this would

be reported on at FYA.

Badgers – an artificial sett was constructed and the existing sett closed under licence

from English Nature. The sett was monitored and the level of activity indicated that it was

being used on a regular basis and it was expected that the new sett would provide a

suitable long-term refuge for badgers excluded from the sett which was closed. No

further monitoring of badger activity at the artificial sett was required. As expected in the

ES, no other badger mitigation measures were considered necessary. Based on animal

mortality data at OYA the scheme did not appear to have affected badger casualties. No

further monitoring was required.

Reptiles - The translocation of reptiles from the footprint of the scheme and erection of

exclusion fencing was undertaken as expected. Monitoring of the reptile population was

specified and this would be reported on at FYA.

5.70 Based on the information available it was assumed that the impacts on the biodiversity

sub-objective were as expected.

Consultation

5.71 Devon County Council confirmed that two of the plots it will be taking over (plots 19 and 22)

contain species rich grassland and at the time of the joint site visit in September 2011 plot 19

and the verge of plot 22 had not developed a full closed sward and more time was required to

allow for the colonisation of wildflower species and the formation of a closed sward. At the

time DCC noted that the need for additional reseeding (with the same seed mix as originally

used) could be assessed if the closed sward fails to evolve prior to handover.

5.72 DCC has not visited the site recently and although not suggesting or requesting that remedial

steps be taken, it would like some reassurance from the HA that this issue has been

appropriately considered.

5.73 DCC also noted with regard to self-seeded gorse that it was agreed at the joint site visit that

where gorse had established it would be treated prior to handover. Unless treated there is a

risk that gorse encroachment could compromise the original design objectives.

Evaluation

A copy of the HEMP has been provided to POPE and this includes recommendations for

future management regimes taking biodiversity into account;

Hedgerow maintenance would avoid harm to Dormice and nesting birds, including special

care being taken to avoid damage to Dormouse nest boxes and tubes that are located in




established hedgerows and woodland areas that were retained undisturbed beyond

construction areas.

Species-rich grassland should be allowed to develop and be maintained – invading scrub

should be controlled. The level of cutting will depend upon how well the grassland

establishes.

As required by the Dormouse licence, the management requirements for woodland areas

have been set out in the HEMP.

Dormouse monitoring would continue in 2011 and until May 2012 with results provided to

Natural England and the Devon Biodiversity Records Centre. In addition, Dormouse nest

tubes would be placed in the new vegetation in May 2012.

Monitoring of the reptile population would be undertaken in September 2011 and May

2012 to determine the success of the project. The records would be sent to the Devon

Biodiversity records Centre.

5.74 At OYA, it was considered too early to evaluate the establishment of species rich grassland.

The HEMP states that a particular feature of the design of the scheme was not to spread

topsoil on areas to be grassed. This was to allow the natural recolonisation of native species

and to encourage the growth of wildflower species that would otherwise be out-competed by

rank grasses. A low maintenance seed mix was chosen to reduce the amount of cutting

necessary. The HEMP notes that the grassland areas established very slowly in the early

years and that maintenance of grassland outside verges and visibility splays during the five

year aftercare period has included cutting once per year in September with gorse removal

identified to be carried out prior to handover in June 2012. Figure 5.6 illustrates that this has

happened, although some gorse was evident during the FYA site visit in the central reserve

and in the vicinity of the attenuation pond (see Figure D.8 in Appendix D.2).

Figure 5.6 – Example of gorse control, with spray drift also affecting adjacent grassland

5.75 Based on the FYA site visit, grassland areas have generally become established although

this is noticeably slower on some of the cutting/embankment slopes and verges (Figure 5.7

below).




Figure 5.7 – Example of bare substrate on cutting slope which vegetation is slowly beginning to

colonise and in time is likely to increase through natural regeneration

5.76 The grass seed mix was agreed with Devon CC and included Fescues, Bents and Meadow

Grass. No specific information has been made available to POPE which would confirm the

current status of species diversity within the grassland areas.

5.77 With regard to Dormice, for monitoring purposes, 20 Dormouse nest tubes were installed in

June 2007 in the retained vegetation adjoining the newly planted vegetation around the

junction. The 17 Dormouse nest boxes were concentrated in the woodland and high value

hedgerows north-east and south-west of the junction and in the retained vegetation alongside

the A30 where signage works were completed in 2006.

5.78 The final Dormice monitoring report has been provided to POPE which concludes that

“Dormice are still present around the Merrymeet junction and are breeding. Nests have been

found in both boxes and tubes across all areas of the site in all types of suitable vegetation.

The fact that Dormice have been recorded in all types of suitable habitat surrounding the

junctions suggests that once the newly planted vegetation has become more established it is

likely that Dormice will also use this”. It also notes that “The nest boxes and nest tubes

installed as mitigation are of benefit to the species by providing additional nesting

opportunities”.

5.79 With regard to reptiles, two years of monitoring was required as part of the mitigation strategy

to assess the success of the mitigation and the Final Reptile Monitoring Report has been

provided to POPE. It notes that reptiles were recorded on only one of the seven survey visits

in 2011(August and September) and this was a Common Lizard. Common Toads were

recorded on every visit. It was noted on the third visit that much of the road verges had been

cut by machine which rendered the habitat less suitable for reptiles. The report considered

that this constraint may have affected the survey results thereafter.

5.80 The Reptile Monitoring report concludes that “while reptiles still inhabit the monitoring area,

albeit in low numbers, there is little evidence to suggest that at this stage in the regeneration

of habitat that favourable conditions have been achieved. It is likely that as the habitat

matures there will be a natural colonisation of reptiles to the affected areas, but at this stage it

appears that this has not yet happened to any great extent”.

5.81 At OYA the MAC provided animal mortality data for the A30 Merrymeet junction. Although

this might not be exhaustive, it showed one badger casualty in 2004 prior to the scheme,

none during construction and after opening one in 2007 and one up to May 2008, indicating

that the scheme did not appear to have affected badger casualties.

5.82 The situation remains the same at FYA with animal mortality data from May 2008 up to

January 2012 in the immediate vicinity of the junction showing one badger casualty in 2009.




5.83 It is considered at FYA that impacts on Biodiversity are as expected; measures have been

taken to reduce the effects of the scheme on protected species including badger, dormouse,

birds and reptiles. Dormice are still present around the junction and are breeding, although at

this stage favourable conditions for reptiles to recolonise the habitat areas does not appear to

have been achieved. New planting has mitigated for the loss of existing vegetation and with

continued management grasslands are likely to develop some species diversity as expected.

Heritage

5.84 The AST stated that the no nationally important archaeological sites or buildings would be

affected by the proposals. There would be loss of potential archaeological deposits identified

by geophysical survey and approximately 170m of historically ‘important’ hedgerows would

be removed.

5.85 The ES noted that the study area contained no scheduled monuments, conservation areas,

registered parks and gardens or historic battlefields. The granite gateposts of Narraway

House to the north of Whiddon Down are Grade II listed these would not be affected by the

scheme.

5.86 There would be some loss of historically important hedge-banks in an area where previous

road improvements have already affected the field pattern.

5.87 A programme of monitoring and investigation during construction would be carried out to

record any significant archaeological deposits or features which might be encountered. Any

significant archaeological finds would be analysed and the results published.

5.88 The OYA report noted that:

The Grade II listed gateposts at Narraway House which were considered to be of local

importance were not affected by the scheme as expected.

It was confirmed that recording of the removal of historically important hedgerows was

undertaken and a copy of the archaeology report was provided.

The site archive would be presented for permanent storage at the Royal Albert Memorial

Museum in Exeter. At OYA it was understood that the archive would be deposited

before the end of the year (2008).

A short note had been produced for the Devon County Archaeological Journal but at

OYA it was not certain if it had been printed, this was being checked by the Contractor

and if necessary it would be resubmitted for the 2009 journal.

As the Devon County Archaeologist had not received a copy of the archaeological report

it was suggested that they be provided with a copy.

Consultation

5.89 Devon County Council has confirmed at FYA that a copy of the archaeology report has been

provided for its records.

5.90 The Archaeological consultant explained that the Royal Albert Memorial Museum in Exeter

has a moratorium on accepting archives for long-term storage and that they (the

Archaeological Contractor) is holding the archive for this scheme pending a decision from the

Museum on new accessions.

5.91 With regard to the article for the Devon County Archaeological Journal, having checked the

records it would appear that this has not been submitted yet and will be for the next

proceedings which will be the 2013 issue.




Evaluation

5.92 The Archaeological Assessment Report notes that a series of former field boundaries were

recorded and correspond to boundaries illustrated on 19th century tithe maps. Several

hedgebanks considered to be of historical importance were breached during the development

work and only one revealed any dating evidence; a damaged base of a hand blown glass

bottle of probably 17- 18th century date (the reports says that this would not be retained).

5.93 One undated length of an earlier field boundary ditch, not related to the Tithe field pattern,

was the only additional archaeological feature recorded.

5.94 At FYA impacts are considered to be as expected.

Water Quality and Drainage

5.95 The AST stated that environment surface water drainage from new carriageway areas would

use the existing surface water drainage system and that additional paved area would be

mitigated by additional attenuation/ interception. A neutral impact was assessed overall.

5.96 The ES noted that the scheme crosses high ground at the headwaters of the River Teign.

When open to traffic, the majority of the road drainage would be directed to an attenuation

pond, the remainder would discharge to existing outfalls. The pond would intercept

accidental spillage of pollutants and control rate of discharge to the local watercourse. The

flow regime of existing watercourse would not be affected by the scheme.

5.97 The OYA report concluded that, as expected, road drainage for the central section of the

scheme was directed to the new attenuation pond, with the remainder discharging to existing

outfalls. Rates of discharge were attenuated and pollution control measures had been

incorporated into the attenuation pond.

5.98 At the request of the Environment Agency (EA), the central reserve was seeded and not hard

paved. The drainage system incorporated various surface and ground water collecting types

including open drainage channels at the top of cuttings and combined filter/carrier drain within

the eastbound loop.

5.99 Stone filled Counterfort drains incorporated into the steeper cutting slopes to prevent erosion

and soil slippage were visually prominent at OYA. Slopes were stabilised using geotextile

mat on slopes steeper than 1:3, with the grass mix hydraseeded.

5.100 Based on the information available and confirmation from the Environment Agency that the

scheme had been constructed in accordance with EA requirements, it was assumed that the

impacts on the water sub-objective were as expected at OYA.

Consultation

5.101 The EA confirmed that in 2012, it was not aware of any problems with the scheme.

Evaluation

5.102 The Counterfort drains are still conspicuous at FYA (Figure 5.8 below); although where they

are located within planting plots, once planting reaches canopy closure the stoned surface

will be concealed. Figures D.15 and Figure D.16 in Appendix D.2 illustrate the attenuation

pond at FYA compared to OYA.

5.103 No new information has been made available to POPE that would indicate that drainage is

performing other than as expected and it is assumed that the impacts on the water

sub-objective remain neutral as expected.




Figure 5.8 – View from A30 overbridge to counterfort drains alongside east bound carriageway

Journey Ambience

5.104 The AST stated that there would be no change to Traveller Care Indicators and views would

be largely unchanged. Stress would remain low with the scheme in place. The impact was

assessed as neutral overall.

5.105 The ES stated that the traveller views from the A30, A382 and C50 would be largely

unchanged as a result of the scheme; restricted in close proximity to the junction in cutting

and more open on the A30 further east and west. There would be new views to the

southwest from the Merrymeet overbridge.

5.106 Driver stress would be reduced due to improved safety, reduced delays and improved

journey time reliability. The quantified assessment showed driver stress to be low for both the

Do Minimum and Do Something scenarios.

5.107 Traveller facilities would still be accessible at Whiddon Down Services. The existing A30

lay-by located 500m west of the existing roundabout would be closed to avoid conflict of

vehicle movements. Other existing lay-bys on the A30 outside the scheme limits would

remain.

5.108 At the OYA stage it was considered that the impact of the scheme on journey ambience was

generally as expected for driver views, driver stress and traveller facilities. Anecdotally, it was

understood that people living locally and commuters had raised concerns about what they

considered to be poor advance signage of the junction.

Consultation

5.109 No responses received.

Evaluation

5.110 Due to the significant variation in traffic flows during the summer months and at holiday

weekends compared to other times of the year, the benefits of the scheme vary throughout

the year, and at the busiest times the long traffic queues at the roundabout are now avoided

as the roundabout been removed.

5.111 Since OYA the advanced directional signs on the A30 have been changed the junction name

to Whiddon Down to avoid confusion with other Merrymeet Junctions.

5.112 Traveller care remains neutral as at OYA.

5.113 Overall at FYA it is considered that impacts are better than expected in the summer months

and at holiday weekends, and as expected at other times of the year.




5.114 Table 5.5 summarises the evaluation of the scheme’s impact on journey ambience.

Table 5.5 – Summary of the schemes impacts on Journey Ambience

Traveller Factor Score FYA evaluation

Views Neutral Traveller views from the A30, A382 and C50 are largely unchanged as a result of the scheme; restricted in close proximity to the junction in cutting and more open on the A30 further east and west. As expected there are new views to the southwest from the Merrymeet overbridge, although these will become more restricted as planting matures.

Stress – (frustration, fear of accidents and route uncertainty)

Beneficial / Neutral depending upon season

The replacement of the roundabout with the junction and overbridge

has reduced delays and improved journey time reliability for through

traffic, which will have reduced the frustration element for drivers. The

removal of the roundabout and associated long delays during the

summer months and holiday weekends will have reduced the fear of

potential accidents for drivers.

Signing has been improved since OYA with local destinations now identified. The junction is also now known as Whiddon Down and the advanced directional signs have been changed to reflect this, which has helped avoid potential confusion with other Merrymeet junctions in the South West.

Care Neutral The Whiddon Down services remain accessible from the A30 and are

signed off the dual carriageway. There is no evidence to suggest that

the closing of the lay-by has been problematic for drivers.

Summary Score Beneficial/Neutral

Beneficial for summer months and holiday weekends.

Neutral at other times of year.

Physical Fitness

5.115 The AST stated that there would be no change in the number of trips by pedestrians or

cyclists with a neutral impact assessed.

5.116 The ES stated that there were no existing facilities for pedestrians, cyclists or equestrians to

cross the A30 at the existing roundabout. The volume and speed of traffic meant that

crossing was very hazardous. As there was no evidence of significant demand, no provision

would be made for additional facilities.

5.117 A wider verge would be provided on the loop road and overbridge, which could provide a safe

route for pedestrians. The ES suggested that this verge could be upgraded to a segregated

route should a demand be identified after the scheme was opened. Cyclists and equestrians

would be encouraged to use the new carriageway over the A30.

5.118 At OYA Devon CC commented that reports received from cycle users indicated that they

welcomed the new junction as it was safer than the previous roundabout as the severance

issues were reduced. Signage warning drivers that cyclists use the area would have been

helpful, as would signage indicating to cyclists that there were alternative quieter

long-distance parallel routes available, by using the ‘old’ pre-1970s A30.

5.119 No information was made available with regard to pedestrian or equestrian use of the

overbridge.




Consultation

5.120 DCC stated that Whiddon Down interchange is one of the options they are considering for

managing the Cycle West route from Exeter to Okehampton.

5.121 The DCC Road Safety Audit team considered the junction safe, convenient and comfortable

due to its open landscaping

Evaluation

5.122 At OYA eight cyclists were observed crossing the A30 via the overbridge in the 12 hour

manual count period. At FYA twelve cyclists were observed in the 12 hour count period. This

would suggest that the opportunity presented by the overbridge for safe crossing is still being

taken albeit by small numbers of users.

5.123 As at OYA, no information on pedestrian or equestrian use of the overbridge has been made

available for this evaluation. The wide grass verges have been maintained and continue to

allow access via the loop roads to the overbridge (see Figure 5.9 below). There is only a

narrow hard paved area across the bridge itself.

5.124 It would appear that there has been insufficient demand post opening for the facilities to be

upgraded to a segregated route and impacts are considered to be neutral as expected.

Figure 5.9 – Grass verge at edge of loop road carriageway, providing safe crossing of the A30

Summary of Evaluations

5.125 The following table represents a summarised evaluation of the effects of the scheme on the

current WebTAG environment sub objectives. The forecast score of the AST is compared

against the evaluation at this FYA stage.




Table 5.6 – Summary of Environment Sub-objectives Evaluations

Origin of

Assessment AST

(Forecast)

EST (OYA

Evaluation)

EST (FYA Evaluation)

Sub Objective Summary Assessment

Noise Not significant Not

summarised

Based on the before scheme and FYA observed

traffic data it can be assumed that in line with POPE

methodology noise due to traffic is as expected for

the A30 and C50 i.e. the changes in flow are no

more than +25% (increase) or -20% (decrease)

than forecast, including HGVs

For the A382 west of the junction overall traffic is

21% greater than expected, however, HGV

numbers have increased by 49% and it is possible

therefore that noise due to traffic could be worse

than expected for the 3 properties and Travelodge

within 300m of this route, and for the village of

Whiddon Down where it was not expected in the ES

that any noise impacts would occur.

Not significant As Expected for

A30 and C50

Worse than Expected for

A382

Local Air Quality Not significant Not

summarised

Observed traffic flow has not changed significantly

as a result of the scheme. There are no properties

within 200m of the A30 east of junction, and only 1

property within 200m of the A382. As traffic flows

on the A382 are relatively low it is unlikely that the

higher observed traffic and HGVs would cause any

breach in air quality criteria, especially given the

rural nature of the area.

Not significant

As Expected

Greenhouse

Gases (Carbon

tonnes / year)

Slightly

adverse

Opening Year

+ 39

Better than

expected

Using the observed flows and latest version of

COBA total Carbon emissions are much higher than

expected because observed traffic flows are much

higher than expected. However, the Base flows

were also much higher so the net change in Carbon

emissions is much lower than expected at +3

tonnes/year in 2008 and +16 tonnes per year in

2012.

Not significant

Better than

expected

Landscape Neutral As expected

Landscape planting is establishing satisfactorily and

subject to ongoing maintenance and management

should reach its longer term objectives for visual

screening and landscape integration by the design

year.

Neutral As

Expected

Townscape Not significant N/A N/A

Biodiversity Slight adverse As expected

Measures have been taken to reduce the effects of

the scheme on protected species including

badgers, dormice, birds and reptiles. Dormice are

still present around the junction and are breeding,

although at this stage favourable conditions for

reptiles to recolonise the habitat areas does not

appear to have been achieved. Limited loss of

some parts of ancient Devon hedge banks as

expected. New planting has mitigated for the loss of

existing vegetation and with continued management

grasslands are likely to develop some species

diversity.

Slight Adverse

As Expected




Origin of

Assessment AST

(Forecast)

EST (OYA

Evaluation)

EST (FYA Evaluation)

Sub Objective Summary Assessment

Heritage Slight adverse Not assessed

Archaeological mitigation was undertaken as

proposed in the ES including recording of

historically important hedgerows. One undated

length of pre 19thC field boundary ditch was the

only additional archaeological feature recorded. At

FYA outstanding reporting issues have been

resolved.

Slight Adverse

As Expected

Water Neutral As expected

Mitigation measures have been incorporated into

the scheme in accordance with EA requirements

and there is no information available to POPE

which would indicate that they are performing other

than as intended.

Neutral As Expected

Journey Ambience Neutral Slightly worse

than expected

Traveller views largely unchanged

Driver stress benefited through reduced delays and

improved journey time reliability for through traffic

particularly during peak holiday times

Signing has been improved since OYA

The services remain accessible closing the lay-by

does not appear to have been problematic.

Better than

expected peak

holiday times

Neutral As

Expected other

times of year

Physical Fitness Neutral As expected Cyclists continue to use the overbridge as a safe

means of crossing the A30. No specific information

available for pedestrian or equestrian usage and it

would appear that there has been insufficient

demand post opening for the facilities to be

upgraded to a segregated route, however. the wider

grass verges are maintained allowing pedestrian

access via the loop roads as expected.

Neutral As Expected




Key Findings on Section 5: Environment

Noise

At FYA traffic flows on the A30 are in line with forecasts and it is assumed that noise

due to traffic is as expected. On the A382, HGV numbers are 49% higher than before

the scheme and noise could be worse than expected for the few properties nearby and

for Whiddon Down where no noise impacts were expected as a result of the scheme.

Local Air Quality

Although traffic flows are higher than expected on A382 and A30 east of the junction,

overall traffic changes due to the scheme are low and it is unlikely that they would

cause any breach in air quality criteria, especially given the rural nature of the area.

Greenhouse Gases

Negligible increase of 1% additional carbon emissions with scheme at FYA, similar to

forecast.

Landscape

Landscape planting is establishing satisfactorily and subject to ongoing maintenance

and management should reach its longer term objectives for visual screening and

landscape integration by the design year.

Biodiversity

Measures have been taken to reduce the effects of the scheme on protected species

and new planting mitigates for the loss of vegetation. Dormice are still present around

the junction and are breeding, although at this stage favourable conditions for reptiles

to recolonise the habitat areas does not appear to have been achieved.

Heritage

Archaeological mitigation was undertaken as proposed in the ES including recording of

historic hedgerows and very little of archaeological interest was found.

Water

Mitigation measures have been incorporated into the scheme in accordance with EA

requirements and based on the information available there is nothing to suggest that

they are performing other than as intended.

Journey Ambience

Traveller views are largely unchanged as expected.

Driver stress has benefited by reduced delays and improved journey time reliability for

through traffic particularly during peak holiday times. Signing has been improved since

OYA.

The services remain accessible and closing the lay-by does not appear to have been

problematic for drivers.

Physical Fitness

Cyclists continue to use the overbridge as a safe means of crossing the A30. It would

appear that there has been insufficient demand post opening for the facilities for

pedestrians to be upgraded to a segregated route although ongoing maintenance of

the wider verges allows continued pedestrian access to the overbridge.




6. Accessibility and Integration

Accessibility

Severance

6.1 The AST forecast no direct severance effects from this scheme.

6.2 The only specific provision for vulnerable users in the scheme is the inclusion of a footway on

the western side of the overbridge follow recommendation by the Road Safety Audit.

However, there is no footpath on the approaches to the junction and overbridge.

6.3 As noted in the OYA report, the new overbridge at the junction enables pedestrians and

cyclists to cross the A30 dual carriageway potentially more safely and with reduced delays.

6.4 Counts of cyclists using the junction were included in the 12hour manual classified counts

undertaken for the one and five years after studies. These showed that:

In the 12 hour period on the weekday survey dates there were eight cyclists in 2008 and

in 2012 there were 12.

All surveyed cyclists travelled between the A382 and the minor roads north of the

junction using the overbridge.

6.5 Given that there are few houses and no services on the northern side of the A30 at this

location it is very likely that the number of pedestrians using the route is also low.

Integration

6.6 The OYA study concludes that the forecasts for the impact of this scheme on the integration

sub-objectives were all as expected.

6.7 There was a beneficial impact forecast on Land-use Policy and the OYA study found the

scheme was consistent with a number of regional and local policies which supported the

scheme specifically or its contribution to the general objective to improve the region’s

transport network.

6.8 At the FYA stage, there has been no change to the land use policy of the rural area within

which the junction is located, hence that impact is neutral while the wider policies which

support schemes to maintain and enhance the trunk road network remain broadly similar,

thus the evaluation of beneficial impact observed at OYA remains valid.

Key findings from section 6: Accessibility and Integration

Accessibility

The scheme was not expected to have accessibility benefits.

The overbridge route provides a better crossing of the A30 for cyclists and pedestrians

than the former roundabout. However there are few of these users here and there is no

formal provision except a footway on the bridge.

Integration

At OYA it was confirmed that the scheme was consistent with policies in place at the

time of its construction and there has been no significant change since, hence

evaluation is a beneficial impact due to its contribution toward improving transport links

to regeneration areas in Cornwall and North Devon.




7. Conclusions 7.1 To conclude this report, this section summarises the scheme’s success in meeting its specific

objectives, and assesses the scheme’s impacts against those forecast.

Success against Objectives

7.2 Objectives can be categorised as follows:

NATA (New Approach to Appraisal) objectives: Impacts are assessed against the

Government’s five objectives for Transport; environmental impact, safety, economy,

accessibility and integration; and

Scheme specific objectives.

7.3 The success of the scheme measured against the NATA objectives is presented in Appendix

A, in the form of an Evaluation Summary Table (EST).

Scheme Specific Objectives

7.4 Drawing upon information presented in this report, a summary of the scheme’s success

against the scheme specific objectives listed previously in the Introduction of this report is

provided in Table 7.1 below. .

Table 7.1 – Success against Scheme specific Objectives

Objectives (from Non-technical Summary and Appraisal Summary Table) Objective

Achieved?

Improve safety at the junction by removing problems particularly associated with A30 traffic stopping at the roundabout, including a high rate of fatalities.

Yes

Reduce congestion occurring at the roundabout at peak times, and during the holiday period.

Yes

Reduce journey times for A30 through traffic. Yes

Retain a full movement junction. Yes

Avoid environmental impact on Dartmoor National Park which lies on the highway boundary.

Yes

Reduce environmental effects as far as practicable. Yes

7.5 In summary, the results in Table 7.1 show that based on the data available at this Five Years

After (FYA) stage, the junction improvement at Whiddon Down on the A30 has achieved all of

its specific objectives.




Appendix A AST and EST




Table A.1 – Appraisal Summary Table (Scheme Assessment Report, January 2003)

Option

Grade Separated Junction

Description: Existing junction on A30 at Merrymeet grade separated by removing the roundabout and providing a free flowing A30 with associated merge and diverge lanes and a

connecting bridge.

Problems: This is the only roundabout along the A30 Dual Carriageway between Exeter and Okehampton, requiring drivers to slow down and Give Way. The roundabout has

an accident problem and suffers frequent delays, particularly during times of peak holiday traffic.

Present Value of Costs to Government: £6.5m

OBJECTIVE

SUB-OBJECTIVE QUALITATIVE IMPACTS QUANTITATIVE ASSESSMENT ASSESSMENT

Environment

Noise Noise levels not assessed as change in traffic levels < 25% Not assessed. Not significant

Local Air Quality No changes in traffic flows of 10% or more are expected as a result of the Published Scheme. Local Air Quality has therefore been scoped out from the appraisal as per guidance in TAG Unit 3.3.1

Not assessed. Not significant

Greenhouse Gases For both 2006 and 2021 scenarios, the total CO2 emissions predicted with the Scheme in operation (Do-Scheme) are slightly higher than those predicted for the Do-Minimum scenario.

The effect of Scheme is therefore considered to be slightly adverse.

CO2 – tonnes per year

DO MINIMUM

Present (2003) = 3,543

Do-Minimum 2006 = 3,860

Do-Minimum 2021 = 4,366

DO SOMETHING

Do Something 2006 = 4,276

Do Something 2021 = 4,760

CO2 – tonnes per year (Change)

2006 (DM - DS) = + 416.01

2021 (DM - DS) = + 394.82

Landscape Some loss of established highway planting but some attenuation of notch effect of A30 seen from NW. New planting, reduced lighting and new bridge would redress the balance.

Neutral

Townscape Not applicable Not significant

Heritage of Historic Resources

No nationally important archaeological sites or buildings will be affected by the proposals. There would be a loss of potential archaeological deposits identified by geophysical survey and approximately 170m of historically ‘important’ hedgerows also would be removed.

Slight adverse

Biodiversity Some species rich Devon hedgebanks would be partially lost, together with some areas of species rich grassland, although both would be largely mitigated by new planting. Some minor impact is likely on habitats for reptiles, badgers, dormice and breeding birds, although these are largely mitigated within the scheme design.

Slight Adverse

Water Environment Surface water drainage from new carriageway areas to utilise existing surface water drainage system and additional paved area mitigated by additional attenuation/interception.

Neutral

Physical Fitness No change in number of trips by pedestrians or cyclists Neutral

Journey Ambience No change to Traveller Care Indicators, views would be largely unchanged. Stress would remain as Low with the scheme in place.

Not applicable Neutral

Safety

Accidents Total Accident Impact identified at this stage Decrease 243 PIA (60yr Low Growth)

Decrease 287 PIA (60yr High Growth)

PVB £21.1m Low Growth

PVB £24.7m High Growth

Security Reduced congestion, large reduction in traffic slowing down. Neutral

Economy

Transport Economic Efficiency

Reduced congestion and improved journey times as a result of new layout. NPV £32.0m - £39.7m

BCR 5.1-6.3

Consumer Users PVB £10.6m-£12.7m

Business Users PVB £8.2m-£9.9m

Public Accounts PVC £7.9m-£7.5m

Reliability Scheme causes slight improvements in journey times through junction. Driver Stress – Do Min 28%. Do Something 28%

Neutral


Not designated Regeneration Area – However does serve Devon and Cornwall Regeneration Area

Development depends on scheme

No

Accessibility

Option Values Not applicable for road schemes N/A

Severance No direct severance effects Neutral

Access to the Transport System

No provisions for the increase of routes or frequency of public transport Neutral

Integration

Transport Interchange None N/A N/A

Land-use Policy Facilitation of national, regional and local transport and economic policies outweighs hindrance of regional and local polices on protection of agricultural land, landscape and cultural heritage

Beneficial

Other Government Policies

Complies with relevant Government policies Neutral




Table A.2 – Evaluation Summary Table (EST)

OBJECTIVE

SUB-OBJECTIVE

QUALITATIVE IMPACTS QUANTITATIVE ASSESSMENT

ASSESSMENT

Environment

Noise The change in traffic flow due to the scheme has been small (<10%), as forecast, so the impact on noise is not significant. There has been a larger increase on the A382 to the West of the junction, especially in HGV numbers, so there could be a slight impact along this route.

N/A Neutral, as expected for A30 and C50. Worse than expected on

A382

Local Air Quality Changes in traffic flow as a result of the scheme have all been small (<10%), as forecast, so the impact on local air quality is not significant. There has been a larger percentage increase in traffic on the A382 through Whiddon Down village but the numbers of vehicles is relatively low and it is unlikely that the additional traffic and HGVs would cause any breach in air quality criteria.

N/A Neutral. As expected

Greenhouse Gases Carbon emissions are much higher than expected because observed traffic flows are much higher than expected. However, the Base flows were also much higher so the net change in Carbon emissions is actually much lower than expected at +3 tonnes/year in 2008 and +16 tonnes per year in 2012.

Forecast (using latest guidance) +39 tonnes

Outturn (2008) +3 tonnes

Outturn (2012) +16 tonnes

Not significant

Better than expected

Landscape Landscape planting is establishing satisfactorily and subject to ongoing maintenance and management should reach its longer term objectives for visual screening and landscape integration by the design year.

N/A Neutral. As Expected

Townscape Not applicable N/A Neutral. As Expected

Heritage of Historic Resources

Archaeological mitigation was undertaken as proposed N/A Slight adverse. As expected

Biodiversity There have been adverse impacts but mitigation measures have been put in place. Hedgebanks have been lost but new planting has been provided and managed

N/A Slight adverse. As expected

Water Mitigation measures were incorporated into the scheme and there is no evidence that they are not working as expected N/A Neutral. As Expected

Physical Fitness Cyclists use the new overbridge but overall volumes of vulnerable users is low N/A Neutral. As Expected

Journey Ambience Traveller views are largely unchanged and driver stress has reduced. Signing improvements have been made since the OYA study and the removal of the lay-by has not caused a problem

N/A Neutral. As Expected

Safety

Accidents There has been a Personal Injury Accident saving of 2.6 per year after an initial accident increase in the first year since opening. The accident saving is one-third less than expected.

Decrease 266 PIA over 60yr PVB £7.4m

Security No change N/A Neutral. As Expected

Economy

Transport Economic Efficiency

Reduced congestion and improved journey times as a result of new layout. Better than forecast NPV 25.1m

BCR 3.6

Consumer Users PVB £13.8m

Business Users PVB £13.5m

Public Accounts PVC £9.5m

Reliability Removal of geometric delay benefits particularly A30 through traffic and right turning movements at peak times N/A beneficial (better than expected)


No local impact but will slightly benefit regeneration areas elsewhere served by the A30 N/A Neutral. As Expected

Accessibility

Option Values Not applicable to road schemes N/A N/A

Severance Bridge reduces severance for small number of users, but no formal provision except footway on overbridge. N/A Neutral. As Expected

Access to the Transport System

No impact N/A Neutral. As Expected

Integration

Transport Interchange

None N/A N/A

Land-use Policy General policies unchanged since OYA N/A Beneficial. As expected

Other Government Policies

General policies unchanged since OYA N/A Neutral. As Expected




Appendix B : Traffic

B.1 Further traffic data

Sources of A30 traffic data

B.1.1 Figure B.1 summarises the TRADS data sites used in this report for A30 traffic data.

Figure B.1 – TRADS sites on A30

Table B.1 – TRADS sites on A30

Site ref Location Period producing

data

1/607 and 1/608 West of the A377, west of Exeter urban area 1995-2005

1/30012532

1/30012533 West of the scheme

2005- current

1/30012538

1/30012539

West of the scheme

between the A382 and the B3250 (Okehampton)

2005- current

B.1.2 Although the sites 607 and 608 are not in the same location as 30012532/3 there are no

junctions other than with minor roads between, thus these two pairs of sites can be

considered directly comparable. Figure B.2 shows the long-term trend from these sites.




Figure B.2 – Long term trend on A30

B.1.3 To supplement the average weekday traffic figures given in Table 2.1, the equivalent average

daily figures are presented in Table B.2.

Table B.2 – Average Daily Traffic volumes around the Junction

Location

Average Daily Traffic (AADT) % change

Before One Year

After Five Years

After One Year

After Five Years

After

A30 east of jct 28,800 29,400 30,200 2% 5%

A30 west of jct 25,400 26,300 26,600 4% 5%

A382 Whiddon Down 6,500 6,300 7,400 -3% 14%

Minor rd 1,400 1,000 1,200 -24% -10%

Total through jct 31,000 31,500 32,700 2% 6%




Appendix C : Statistical Significance Tests

on Safety Data

This appendix details the statistical significance testing undertaken on the accident data used in the safety section 3 of this report.

C.1 Significance of Difference in numbers of

Accidents and Casualties in before and after

periods Chi-square Tests by Time period

C.1.1 The Chi-Square test is a statistical test which can be used to test whether the difference in

accident numbers in the two five year periods is significant or not compared to the null

hypothesis that there is no change in the accident rate over the two periods. This test was

used on the accident and casualty numbers as shown in section 3 of the main report Table

3.1 to 3.4 to determine whether the number of occurrences in the five years after period was

significantly different to the number in the five years before period. This tests the likelihood

that the figures could have occurred by chance or are really different using a confidence level

of 95%.

C.1.2 The results of the tests are shown in Table C.1.

Table C.1 – Statistical Significance Tests on Changes in numbers of Accidents and Casualties before

and after

Area Test: Change in numbers of Conclusion

A30 2km around Whiddon Down junction

Personal Injury Accidents Reduction is not significant

Personal Injury Accidents (considering only 3.5 years since 2008)

Reduction is not significant

Casualties Reduction is not significant

All accidents including damage only Reduction is significant

Narrow area 0.5km around Whiddon Down junction

All Accidents Reduction is significant

All Casualties Reduction is significant

All accidents including damage only Reduction is significant

C.1.3 It can be seen from Table C.1 that the reductions in personal injury accident and casualties

are statistically significant only within the 0.5km area focussed around the junction.

C.1.4 These findings indicate that it is likely that there is a real reduction in the number of accidents

and casualties rather than it having occurred by chance alone. Thus we can infer that the

scheme is responsible for the reduced accident and casualty numbers in the post opening

period. However, it is widely recognised that national statistics on road accidents show a

long-term trend towards a reduction in road accidents17

. Hence, at least some of the

17 Reported Road Casualties Great Britain, DfT




reduction in accidents can be attributed to national trends so we now consider further tests to

compare the trend observed in the area around the scheme with a comparable rural section

of the A30 between the Whiddon Down junction and Exeter, namely a section including the

Woodleigh junction near Cheriton Bishop. This is examined in the sub-section below.

C.2 Significance of changes in Accident numbers

Compared with Control site C.2.1 It is widely recognised that accidents numbers generally are declining over time. For this

reason DfT guidance on monitoring the effectiveness of read schemes recommends the use

of a control site18

. The control site needs to share all the characteristics of the scheme site.

C.2.2 The two statistical tests recommended in DfT guidance19

using a control site are:

The Tanner k test can be used to show how the accident numbers at a site change

relative to control data.

The chi-squared test can be used to determine whether the change in accidents was

produced by the treatment or whether this occurred by chance. This test thus determines

whether the change is statistically significant.

C.2.3 In the scope of this study, the control site is taken as a section of the A30 which is similarly

rural in nature having the national speed limit and including an all-movements

grade-separated junction.

C.2.4 The accident numbers at the control section of the A30 and the narrow scheme extent used

in these tests are shown in Table C.2.

Table C.2 – Accident numbers in before and after periods on scheme section and at control section

Five Year Period

Number of Accidents on A30

Total 0.5km around Whiddon Down

jct

A30 near Woodleigh jct

Before (a) 21 (c) 7 (g) 28

After (b) 7 (d) 5 (h) 12

Total (e) 28 (f) 12 (n) 40

Tanner k test

C.2.5 The Tanner k test is used to show how the accident numbers at a site change relative to

control data. In the case of this scheme, we have compared the accident rate on the section

of the A30 including Whiddon Down junction with the improvement on the section of the A30

near the Woodleigh junction which has not been subject to any significant safety

improvements within this time period.

C.2.6 Table C.3 shows how this has been calculated based on the figures in Table C.2 and the

conclusions which are drawn.

18 A Road Safety Good Practice Guide for Highway Authorities 2

nd edition, DfT

19 Ibid, Appendix B




Table C.3 – Tanner k test results on accident numbers within scheme area only

Formula Data Result Conclusion

k = b/a

d/c Accidents 0.47

as k < 1 there has been a decrease in accidents numbers relative to the control.

The decrease is 53 %

C.2.7 The results of the Tanner k test shown in Table C.3 show that the change in accident

numbers on this narrow section around the junction is statistically significant, representing a

real saving of 53% when compared with the reduction in numbers observed on a control

section of the A30 during the same period.

Chi-square Tests on Accident Numbers within scheme area only compared with control

site

C.2.8 We now test how confident we can be that the greater reduction in accidents around the

junction compared to the control section of the A30 is due to chance, or is likely to be directly

as result of the scheme. For this we use the chi-square in which the null hypothesis is that

the reduction in the accident rate between the before and after periods within the scheme

extent of the A30 is the same as that observed at the control section of the A30. The

chi-square formula gives a figure here which is compared with the standard table to give a

significance level. It is normal to consider a level of 95% significance represents a real

change; this requires a chi-square result of greater than 3.84.

C.2.9 Table C.4 shows how this has been calculated based on the figures in Table C.2.

Table C.4 – Chi-square test results

Formula Data Chi-

square Result

Conclusion

Accidents 0.46

The reduction in accidents around the Whiddon Down junction compared with the control section is no better than could have occurred by chance alone, based on a 95% confidence level.

C.2.10 The findings of the statistical tests presented in this appendix are discussed in the main

safety section of this report.




Appendix D : Environment

D.1 Sources D.1.1 Standard list of information required to evaluate the environmental sub-objective.

Environment Specific Requirements OYA FYA

Environment Statement (ES) or if not a scheme requirement the latest Scheme Assessment Report (SAR).

A30 Merrymeet Junction Improvement Volumes 1, 2 and NTS February 2005

As at OYA

AST AST January 2003 As at OYA

Any amendments, updates or addendums to the ES/SAR or any relevant further studies or reports. Any significant changes to the scheme since the ES.

No amendments / significant changes to the scheme since the ES

As at OYA

As built drawings for landscape/biodiversity/environmental mitigation measures/drainage/ fencing/ earthworks etc.

Maintenance Manual and Appendices for Roadworks and Structures on CD including; Specification Appendices.

Planting As-Built

Landscape Design Environmental Masterplan Ecological Design )

As at OYA

Construction Environment Management Plan (CEMP)

Environmental

Management Plan (May

2007) is Appendix N of

the Roadworks

Maintenance Manual

which is included on the

CD.

As at OYA

Landscape and Ecology Aftercare Plan (LEAP).

Not produced for this scheme

H& S File – environment information Not available

Handover Environmental Management Plan (HEMP).

HEMP November 2011 and Handover Site Inspection Record for Environmental Mitigation 29.9.11

Relevant Contact Names for consultation. Provided As at OYA

Archaeological Reports (popular and academic).

Archaeological Assessment Report July 2006

As at OYA

The Road Surface Influence (RSI) value of any low noise surface installed

Provided




Environment Specific Requirements OYA FYA

The insulation performance properties of any noise barriers installed (The BS EN 1794-2 result provided by the noise barrier manufacturer)

N/A N/A

List of properties eligible for noise insulation. None eligible As at OYA

List of Part 1 Claims regarding noise/air quality/lighting

Provided

Reports for any pre/post opening survey and monitoring work e.g. for noise, biodiversity, water quality).

Report on Dormouse Monitoring (June 2008).

Final Dormouse Monitoring Report May 2012

Reptile monitoring to commence in September 2008.

Final Reptile Survey and Monitoring Report May 2012

A Combined Site Completion Report is being prepared for the works at Narraway Farm. These were improvement works to an adjacent field raising its quality from grade 5 to grade 3b and also addressing environmental concerns in respect of the disposal of the surplus materials to landfill.

Not provided

Animal mortality data Provided by the MAC for period 2004 to May 2008

Provided by the MAC for period May 2008 to January 2012

Post opening Non-motorised User (NMU) Audit or Vulnerable User Survey

The scheme predated NMU (Vulnerable) pre & post scheme surveys, this was not required under the contract & therefore none were carried out.

Any information regarding environmental enhancements to streetscape/townscape for bypassed settlements.

N/A N/A

Employers Requirements Works Information – environment section

Some information provided on CD – see above

Provided

Scheme Newsletters /publicity material/Award information for the scheme.

Newsletters obtained from the HA website.

Not aware of any awards

As at OYA

Other Area Road Users Satisfaction

Surveys June 2006 to May 2007 (during the road works)




D.2 Photographic Record of Scheme Including: ES Photomontages and OYA

vs FYA comparisons

ES Photomontage comparisons

Figure D.1 – View westwards from Whiddon Down Services, looking across the Troney Valley to Livaton and the A3124 overbridge (Figure D.2 completes

the panorama to the right).

Figure D.2 – FYA May 2012 similar view (taken from new A30 overbridge) with Narraway Farm to left of view

Narraway Farm




Figure D.3 – ES : View eastwards towards Merrymeet from the A3124 overbridge

Figure D.4 – FYA May 2012 looking along the A30 east towards the Whiddon Down junction and overbridge across the cutting




One Year After / Five Year After Comparison Photos

Figure D.5 – OYA (July 2008) Looking south (with C50 in foreground) to

the new junction with the A30, new planting and seeding on the cutting

slopes. A30 overbridge top right of view.

Figure D.6 – FYA (May 2012) Looking from A30 overbridge towards

C50 and planting on embankment slopes illustrating generally satisfactory establishment.

Figure D.7 – OYA (July 2008) Looking west from overbridge – the pale

green field in the middle foreground (left of the white van) has been

re-profiled with surplus soil and integrates well into the local landscape

Figure D.8 – FYA (May 2012) central reserve grassland slow to establish

as expected on substrate but clear of weeds although gorse establishing

between the barriers. Planting establishing satisfactorily.




Figure D.9 – OYA (July 2008) Looking towards Narroway Farm

from earth mounding adjacent to approach road to the

overbridge. Travelodge is behind trees on left

Figure D.10 – FYA (May 2012) well established planting and no

evidence of noxious weed

Figure D.11 – OYA (July 2008) Looking east along the A30 with

overbridge on horizon visually closing the ‘notch’ in the cutting

Figure D.12 – FYA (July 2012) planting has not yet matured

sufficiently to visually reduce the width of the bridge




Figure D.13 – OYA (July 2008) Wide verge on approach to

Whiddon Down services from the A30

Figure D.15 – OYA (July 2008) View of attenuation pond, dry at time of

site visit, with distant views to Dartmoor National Park beyond.

Textmour reinforced soil slope was use

Figure D.14 – FYA (May 2012) Grass verge at edge of loop road

carriageway, providing safe crossing of the A30

Figure D.16 – FYA (May 2012) Vegetation including Gorse will require

cyclical maintenance and management to ensure attenuation pond

continues to function as intended.




Figure D.17 – OYA (July 2008) Looking from A382. Counterfort

drains visible on cutting slope.

Figure D.18 – FYA (May 2012) similar view with Counterfort drains

still visible. Slow grassland establishment visible on verge in

foreground. Good plant growth in small island planting (to left of

mobile sign).




Appendix E : Glossary

Term Meaning

AADT Annual Average Daily Traffic. Average of 24 hour flows, seven days a week, for all days within the year.

AAWT Annual Average Weekday Traffic. As AADT but for five days, (Monday to Friday) only.

Accessibility Accessibility can be defined as ‘ease of reaching’. The accessibility objective is concerned with increasing the ability with which people in different locations, and with differing availability of transport, can reach different types of facility.

AST Appraisal Summary Table. This records the impacts of the scheme according to the Government’s five key objects for transport, as defined in DfT guidance contained on its Transport Analysis Guidance web pages, WebTAG

BCR Benefit Cost Ratio

This is the ratio of benefits to costs when both are expressed in terms of present value i.e. PVB divided by PVC

CO2 Carbon Dioxide, for transport, this is the main greenhouse gas

COBA COst Benefit Analysis – a computer program which compares the costs of providing road schemes with the benefits derived by road users (in terms of time, vehicle operating costs and accidents), and expresses the results in terms of a monetary valuation. The COBA model uses the fixed trip matrix unless it is being used in Accident-only mode.

DfT Department for Transport

Discount Rate The percentage rate applied to cash flows to enable comparisons to be made between payments made at different times. The rate quantifies the extent to which a sum of money is worth more to the Government today than the same amount in a year's time.

Discounting Discounting is a technique used to compare costs and benefits that occur in different time periods and is the process of adjusting future cash flows to their present values to reflect the time value of money, e.g. £1 worth of benefits now is worth more than £1 in the future. A standard base year needs to be used which is 2002 for the appraisal used in this report.

DMRB Design Manual for Roads and Bridges

DNP Dartmoor National Park

Do Minimum (DM) / Do Nothing (DN)

In scheme modelling, this is the scenario which comprises the existing road network plus improvement schemes that have already been committed.

In the case of this scheme, there were no other improvement schemes, so this was referred to in the appraisal as Do Nothing

Do Something (DS) In scheme modelling, this is the scenario detailing the planned scheme plus improvement schemes that have already been committed

EA Environment Agency

EN English Nature

EST Evaluation Summary Table. In POPE studies, this is a summary of the evaluations of the TAG objectives using a similar format to the forecasts in the AST.

FYA Five Years After




Term Meaning

HA, Highways Agency

An Executive Agency of the Department for Transport, responsible for operating, maintaining and improving the strategic road network in England.

HATRIS Highways Agency Traffic Information System The Highways Agency (HA) currently maintains, operates and develops three traffic databases and associated applications. The Traffic Flow Data System (TRADS) holds information on traffic flows at sites on the network. The Journey Time Database (JTDB) system holds information on journey times and traffic flows for links of the network. These two databases are known collectively as the HA Traffic Information System (HATRIS).

HEMP Handover Environmental Management Plan

HGV Heavy Goods Vehicle. In the context of this report, the precise definition of the term is dependent on the way that traffic is being measured. Currently, traffic flow data as measured by ATCs uses a length based classification – the term HGV is used to refer to vehicles greater than 5.2m. Shorter vehicles are classified as ‘light’.

KSI Killed or Seriously Injured KSI is the proportion of casualties who are killed or seriously injured and is used as a measure of accident severity

LMVR Local Model Validation Report

MAC Managing Agent Contractor – organisation normally contracted in 5-year terms for undertaking the management of the road network within a HA area.

MCC Manual Classified Count

NATA New Approach to Transport Appraisal was the basis of the standard DfT appraisal approach when this scheme was appraised.

NE Natural England

NO2 Nitrogen Dioxide

NRTF National Road Traffic Forecast. This document defines the latest forecasts produced by the Department of the Environment, Transport and the Regions of the growth in the volume of motor traffic. At the time this scheme was appraised, the most recent one was NRTF97, i.e. dating from 1997.

NTS Non-technical Summary of the Environmental Statement Describes the Published Scheme proposals and summarises the Environmental Statement in non-technical language.

OYA One Year After

Part 1 claims This is financial compensation which can be claimed by people who own and also occupy property that has been reduced in value by physical factors caused by the use of a new or altered road.

PIA Personal Injury Accident. A road traffic accident in which at least one person required

medical treatment.

POPE Post Opening Project Evaluation, before & after monitoring of all major highway schemes in England.

PM10 Particulate Matter measuring less than 10µm. This is the generally accepted measure of particulate material in the atmosphere likely to be inhaled by humans

Present Value Present Value is the value today of an amount of money in the future. In cost-benefit analysis, values in differing years are converted to a standard base year by the process of discounting giving a present value.




Term Meaning

PROW Public Right of Way

A public right of way is a way (a route over which people go) over which all members of the public have a right of passage. Public rights of way include footpaths, carriageways, bridleways

PVB Present Value Benefits Value of a stream of Benefits accruing over the appraisal period of a scheme expressed in the value of a Present Value

PVC Present Value Cost As for PVB but for a stream of costs associated with a project

RSA Road Safety Audit

STATS19 A database of injury accident statistics recorded by police officers attending accidents

T&EAR Traffic & Economic Assessment Report

In the case of this scheme, the appraisal of traffic and economic impacts were presented in this single report

TEE Transport Economic Efficiency

TEMPRO Trip End Model Program This is a PC program which provides access to the Department for Transport’s national Trip End Model projections of growth in travel demand, and the underlying car ownership and planning data projections.

TPI Targeted Programme of Improvements. Formerly, this was the title of Highways Agency’s programme of investment in improvements to the Trunk road and Motorway road network comprised of a number of major schemes each costing more than £5m. Now called Major Schemes and is for schemes over £10m.

TRADS Traffic Flow Data System

vpd Vehicles Per Day

VOC Vehicle Operating Costs These are costs to the user of the fuel and maintaining the vehicle.

webTAG Department for Transport’s website for guidance on the conduct of transport studies at http://www.webtag.org.uk/

http://www.webtag.org.uk/




Appendix F : Tables and Figures in this

Report List of Tables

Table 2.1 – Average Weekday Traffic volumes around the Junction 10

Table 2.2 – 12 Hour Traffic movements at junction 12 Table 2.3 – Total 12 hour Traffic flows using junction 12

Table 2.4 – Average Weekday HGV daily flow on non-trunk roads 15

Table 2.5 – Post opening: Forecasts vs. Observed traffic volumes (AADT) 17 Table 3.1 – Number of Personal Injury Accidents (2km/1.2 mile section centred on Whiddon Down) 23

Table 3.2 – Number of Personal Injury Accidents (0.5km/0.3 mile section centred on Whiddon Down) 24

Table 3.3 – Accident Rate Five Years Before and After compared to National Average 27

Table 3.4 – Forecast Personal Injury Accident savings 28 Table 3.5 – Forecast vs. Outturn Accident savings 29

Table 4.1 – Investment costs 33

Table 4.2 – Indirect tax impact 34

Table 4.3 – Present Value Costs 35 Table 4.4 – 60 year Economic Benefits (£m, 2002 prices, discounted) 36

Table 4.5 – Casualty severity modelling 37

Table 4.6 – 60 year Safety Benefits 38

Table 4.7 – Summary of Present Value Benefits 39 Table 4.8 – Present Value Benefits with indirect tax impact 39

Table 4.9 – Benefit Cost Ratio 40

Table 5.1 – Summary of Environmental Consultation Responses 44

Table 5.2 – Traffic Forecasts used in AQ Assessment vs. Outturn Flows 46

Table 5.3 – August Traffic Forecasts used in AQ Assessment vs. Outturn Flows 46

Table 5.4 – Carbon Emissions (tonnes in year) 49

Table 5.5 – Summary of the schemes impacts on Journey Ambience 59 Table 5.6 – Summary of Environment Sub-objectives Evaluations 61

Table 7.1 – Success against Scheme specific Objectives 65

List of Figures

Figure 1.1 – Location of A30 Whiddon Down scheme 1 Figure 1.2 – Scheme Summary 3

Figure 1.3 – Scheme Key Events Timeline 4

Figure 2.1 – National and Regional Traffic Trends compared with A30 traffic 7

Figure 2.2 – National Traffic Trends by Road Type: Rural roads compared with A30 traffic 8

Figure 2.3 – Trends on A30 east and west of the junction-by month 9

Figure 2.4 – AADT Yearly Trends on A30 east and west from 2003 9

Figure 2.5 – Weekday Traffic volumes and Total Flow through Junction 11

Figure 2.6 – August traffic volumes by day of week, by direction, west of jct 13 Figure 2.7 – Average Weekday HGVs on A30 14

Figure 3.1 – Locations of Personal Injury Accidents 2km/1.2miles and 0.5km/0.3miles around junction 25

Figure 4.1 – Forecast benefits 35

Figure 5.1 – Illustrating generally satisfactory plant establishment, weed free circles and grassland free from

noxious weeds 51




Figure 5.2 – (left) Plants developing ‘lollipop’ form in narrow shelters at OYA 52

Figure 5.3 – (right) At FYA plants will not be able to develop a more natural shape until shelters are removed52 Figure 5.4 – (left) Existing night time lighting before the improvement works at the junction 52

Figure 5.5 – (right) At FYA 52

Figure 5.6 – Example of gorse control, with spray drift also affecting adjacent grassland 54

Figure 5.7 – Example of bare substrate on cutting slope which vegetation is slowly beginning to colonise and

in time is likely to increase through natural regeneration 55

Figure 5.8 – View from A30 overbridge to counterfort drains alongside east bound carriageway 58 Figure 5.9 – Grass verge at edge of loop road carriageway, providing safe crossing of the A30 60

APPENDICES

List of Tables

Table A.1 – Appraisal Summary Table (Scheme Assessment Report, January 2003) 67

Table A.2 – Evaluation Summary Table (EST) 68

Table B.1 – TRADS sites on A30 69

Table B.2 – Average Daily Traffic volumes around the Junction 70 Table C.1 – Statistical Significance Tests on Changes in numbers of Accidents and Casualties before and

after 71 Table C.2 – Accident numbers in before and after periods on scheme section and at control section 72

Table C.3 – Tanner k test results on accident numbers within scheme area only 73

Table C.4 – Chi-square test results 73

List of Figures

Figure B.1 – TRADS sites on A30 69 Figure B.2 – Long term trend on A30 70

Figure D.1 – View westwards from Whiddon Down Services, looking across the Troney Valley to Livaton and

the A3124 overbridge (Figure D.2 completes the panorama to the right). 76

Figure D.2 – FYA May 2012 similar view (taken from new A30 overbridge) with Narraway Farm to left of

view 76 Figure D.3 – ES : View eastwards towards Merrymeet from the A3124 overbridge 77

Figure D.4 – FYA May 2012 looking along the A30 east towards the Whiddon Down junction and overbridge

across the cutting 77

Figure D.5 – OYA (July 2008) Looking south (with C50 in foreground) to the new junction with the A30, new

planting and seeding on the cutting slopes. A30 overbridge top right of view. 78 Figure D.6 – FYA (May 2012) Looking from A30 overbridge towards C50 and planting on embankment

slopes illustrating generally satisfactory establishment. 78

Figure D.7 – OYA (July 2008) Looking west from overbridge – the pale green field in the middle foreground

(left of the white van) has been re-profiled with surplus soil and integrates well into the local

landscape 78

Figure D.8 – FYA (May 2012) central reserve grassland slow to establish as expected on substrate but clear

of weeds although gorse establishing between the barriers. Planting establishing

satisfactorily. 78

Figure D.9 – OYA (July 2008) Looking towards Narroway Farm from earth mounding adjacent to approach

road to the overbridge. Travelodge is behind trees on left 79

Figure D.10 – FYA (May 2012) well established planting and no evidence of noxious weed 79

Figure D.11 – OYA (July 2008) Looking east along the A30 with overbridge on horizon visually closing the

‘notch’ in the cutting 79

Figure D.12 – FYA (July 2012) planting has not yet matured sufficiently to visually reduce the width of the

bridge 79

Figure D.13 – OYA (July 2008) Wide verge on approach to Whiddon Down services from the A30 80




Figure D.15 – OYA (July 2008) View of attenuation pond, dry at time of site visit, with distant views to

Dartmoor National Park beyond. Textmour reinforced soil slope was use 80

Figure D.14 – FYA (May 2012) Grass verge at edge of loop road carriageway, providing safe crossing of the

A30 80

Figure D.16 – FYA (May 2012) Vegetation including Gorse will require cyclical maintenance and

management to ensure attenuation pond continues to function as intended. 80 Figure D.17 – OYA (July 2008) Looking from A382. Counterfort drains visible on cutting slope. 81

Figure D.18 – FYA (May 2012) similar view with Counterfort drains still visible. Slow grassland

establishment visible on verge in foreground. Good plant growth in small island planting (to

left of mobile sign). 81

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