Transport Scotland Scottish Trunk Road Infrastructure Project Evaluation Evaluation Report for Trunk Road Projects Opened between April 07 and March 09
A APPENDIX A: EVALUATIONS FOR PROJECTS THAT OPENED BETWEEN APRIL 07 AND MARCH 09
Project Overview
The project involved the construction of a 5.4 kilometre bypass to the north of Dalkeith between the A68(T) at Fordel Mains and the A720(T) Edinburgh City Bypass, with 2.6 kilometres of single carriageway and a 2.8 kilometre southbound climbing lane between the junctions with the A6094 Salters Road and A6106 Fordel Mains.
In parallel and on completion of the bypass construction, Midlothian Council were expected to implement a full closure of Dalkeith High Street to traffic and pedestrianise the historic town centre. Subsequently, however, this did not happen. Following public consultation by the council, the implemented measures included public realm enhancements and traffic calming measures whilst maintaining a through route for traffic.
The general location of the project is shown in Figure A.6a.
The A68(T) Dalkeith Bypass project was officially opened to traffic on 23rd September 2008.
Project Objectives
The objectives of the A68(T) Dalkeith Bypass project were set as follows:
- to provide good quick and reliable inter-urban road links;
- to improve accessibility from Edinburgh to the Central Borders and the North of England;
- to aid economic prosperity and development by reducing travel costs particularly for business and commercial traffic serving existing and proposed business and commercial developments (including tourism and service industries);
- to improve road safety and contribute towards the Government's overall target of reducing road casualties;
- to minimise the intrusion of roads and traffic on communities and on the environment; and
- to use the limited resources available as effectively as possible to achieve good value for money for both taxpayers and transport users.
Figure A.6a A68(T) Dalkeith Bypass
Evaluation Methodology
The A68(T) Dalkeith Bypass project has been evaluated against the above objectives and the following criteria:
- Environment;
- Safety;
- Economy;
- Costs to Government; and
- Value for Money.
As the evaluation focuses on impacts relating to the project objectives, specific evaluations against the Integration and Accessibility & Social Inclusion criteria have not been undertaken.
The evaluation is supported by the consideration of network traffic indicators, including traffic volumes and travel times presented in the following section.
As noted above, the decision to proceed with the project was based on the assumption that there would be a full closure of the High Street in Dalkeith, in line with the proposals of Midlothian Council at that time. Subsequent to public consultation by the council, the implemented measures included public realm enhancements and traffic calming measures, while maintaining a through route for traffic.
For the purposes of evaluation, therefore, the predicted traffic flows and journey times are taken from a model developed during the preparation of the project which better reflects the improvements that were implemented within Dalkeith town centre. This alternate model predicted economic benefits that did not outweigh the cost of the project and was used instead of the main model on which the decision to proceed with the project was based.
A.6.2 Network Traffic Indicators
Traffic Volumes
The locations of Automatic Traffic Counters (ATCs) within the study area are shown in Figure A.6a.
Comparison Between Pre and Post Opening Traffic Flows
The Annual Average Daily Traffic (AADT) flows pre and post project opening on the key routes within the study area are presented in Table A.6.1.
Table A.6.1: A68(T) Dalkeith Bypass - ATC Data
| ATC Reference | AADT by Year | |||||
|---|---|---|---|---|---|---|
| 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | |
| A68(T) Dalkeith Bypass | ||||||
| JTC00506 | - | - | Year of Opening | 10,492 | 10,580 | 11,615 |
| JTC00505 | - | - | 8,675 | 8,935 | 10,030 | |
| A68(T) South of Dalkeith Bypass | ||||||
| ATCSE014 | 11,390 | 11,927 | Year of Opening | 11,707 | 11,988 | 12,536 |
| Bypassed Route through Dalkeith | ||||||
| ATC05078 | 15,464 | 15,328 | Year of Opening | 10,212 | 10,339 | 10,573 |
| ATCSE005 | 16,320 | 15,589 | 8,461 | 8,582 | 9,416 | |
| A720(T) Edinburgh City Bypass (West of Sheriffhall Rb) | ||||||
| JTC00300 | 42,492 | 42,724 | Year of Opening | 43,940 | 43,093 | N/A |
| A720(T) Edinburgh City Bypass (Between Sheriffhall Rb & A68(T) Junction) | ||||||
| JTC00251 | 37,273 | N/A | Year of Opening | 40,121 | 41,123 | 40,652 |
A comparison between the pre and post opening traffic volumes on the bypassed route through Dalkeith, presented in Table A.6.1, indicates that traffic flows in 2009 were 7,100 vehicles per day (vpd) lower compared with 2007 levels within Dalkeith and 5,100 vpd lower south of Sheriffhall Roundabout, suggesting that approximately 45% of traffic previously travelling via Dalkeith town centre now uses the Dalkeith Bypass.
The traffic data indicates that the A68(T) Dalkeith Bypass, between the A720(T) Edinburgh City Bypass and the A6094, carried approximately 10,500 vpd in 2009, 10,600 vpd in 2010 and 11,600 vpd in 2011. To the south of the A6094, the Dalkeith Bypass carried approximately 8,700 vpd in 2009, 8,900 vpd in 2010 and 10,000 vpd in 2011.
Traffic data on the A68(T) to the south of the Dalkeith Bypass indicates that the route carried approximately 11,700 vpd in 2009 and that the traffic flows in 2009 were approximately 200 vpd lower compared with 2007 levels, however, 2010 flow levels were consistent with flow levels in 2007. Traffic flows in 2011 increased by around 550 vpd (approximately 5%) compared to 2010 flow levels.
Traffic flows on the A720(T) Edinburgh City Bypass, between Sheriffhall Roundabout and the A68(T) Dalkeith Bypass, were approximately 37,200 vpd in 2007 and increased to approximately 40,100 vpd in 2009 and 41,100 vpd in 2010 before reducing to approximately 40,700 vpd in 2011. Variations in traffic flows on this section of the A720(T) Edinburgh City Bypass are not unexpected given changes to the pattern of traffic entering and exiting the A720(T) Edinburgh City Bypass from the A68(T) Dalkeith Bypass rather than the bypassed route through Dalkeith.
Traffic flows on the A720(T) Edinburgh City Bypass to the west of Sheriffhall Roundabout were approximately 42,700 vpd in 2007 and increased to approximately 43,900 vpd in 2009, before reducing to approximately 43,100 vpd in 2010.
A comparison of the bypassed route through Dalkeith with the combined Dalkeith bypass and bypassed route traffic flows pre and post opening (i.e. 15,600 vpd vs 19,000 vpd) indicates an overall increase in traffic following opening of 3,400 vpd 22%. The data on the A68(T) trunk road south of the bypass, however, has remained consistent pre and post opening of the A68(T) Dalkeith Bypass which suggests that the increase in combined traffic is due to changes in local traffic patterns within the Dalkeith locality and is not a result of induced traffic on the bypass.
Comparison Between Predicted and Actual Traffic Flows
The opening year flow comparisons for the A68(T) Dalkeith Bypass project is based on AADT flows from 2009 as this was the first full year of reliable traffic data available from Transport Scotland's traffic counters within the study area.
Predicted traffic flows for 2009 were derived by extrapolating from the modelled assessment year, design network flows.
A summary of the actual and predicted traffic data is shown in Table A.6.2 below.
Table A.6.2: A68(T) Dalkeith Bypass - Traffic Analysis Summary
|
ATC Ref |
Actual AADT* | Predicted AADT |
% Difference (Predicted - Actual) / Actual |
|---|---|---|---|
| A68(T) Dalkeith Bypass | |||
| JTC00506 | 10,492 | 10,755 | 2.5% |
| JTC00505 | 8,675 | 8,527 | -1.7% |
| A720(T) Edinburgh City Bypass (West of Sheriffhall Rb) | |||
| JTC00300 | 43,940 | 40,402 | -8.1% |
| A720(T) Edinburgh City Bypass (Between Sheriffhall Rb & A68(T) Junction) | |||
| JTC00251 | 40,121 | 40,877 | 1.9% |
* 2009 flows (first full year of ATC data available)
The comparison between predicted and actual AADT flows in Table A.6.2 indicates that the predicted 2009 flow (derived by extrapolating from the modelled assessment year traffic flows) was between 2% lower and 3% greater than the observed 2009 flow on the A68(T) Dalkeith Bypass, which is well within accepted limits.
Similar comparisons demonstrate that the predicted 2009 flow was 2% greater than the observed 2009 flow on the A720(T) Edinburgh City Bypass between Sheriffhall Roundabout and the A68(T) Dalkeith Bypass and 8% lower than the observed 2009 flow on the A720(T) Edinburgh City Bypass to the west of Sheriffhall Roundabout.
Carriageway Standard Assessment
A single 2-lane carriageway with a climbing lane was constructed to bypass Dalkeith as part of a series of improvements along the A68(T) route, providing dedicated overtaking opportunities between the junctions with the A6094 Salters Road and A6106 Fordel Mains to help reduce journey times and improve journey time reliability.
An assessment of the carriageway standard according to TA 46/97 - Economic Assessment and Recommended Flow Ranges for New Rural Road Links, which applied at the time of the project design, is shown in Table A.6.3 based on the traffic flows observed on the bypass in 2009.
Table A.6.3: A68(T) Dalkeith Bypass - Assessment of Carriageway Standard (TA 46/97)
| Opening Year AADT* | TA 46/97 Standard | Constructed Standard |
|---|---|---|
| 8,675 to 10,492 | Single 2-Lane | Single 2-Lane & Climbing Lane |
* 2009 flows (first full year of ATC data available)
The carriageway assessment indicates that the observed 2009 flow lies within the flow range appropriate for a single 2-lane standard of carriageway. There are no specific flow ranges for the justification of a climbing lane given in TA 46/97 and, given the nature of improvements along the A68(T) route, the constructed carriageway standards are considered appropriate.
Travel Times
Comparison Between Pre and Post Opening Travel Times
Journey time surveys were carried out for the A68(T) Dalkeith Bypass project in September 2005 and March 2012, during the AM and PM survey periods, to provide an indication of the changes in average journey times between Fordel Mains and Sheriffhall Roundabout.
The average post opening savings in travel times between Fordel Mains and Sheriffhall Roundabout using:- (a) the A68(T) Dalkeith Bypass (& A720(T) Edinburgh City Bypass); and (b) the bypassed route through Dalkeith (compared with travel times along the A68(T) route through Dalkeith in 2005) are shown in Tables A.6.4a and A.6.4b respectively.
Table A.6.4a: A68(T) Dalkeith Bypass - Travel Time Savings: A68(T) Dalkeith Bypass
| Direction | AM Peak | PM Peak | ||
|---|---|---|---|---|
| Time Savings (mins / secs) | % Saving | Time Savings (mins / secs) | % Saving | |
| Northbound | - 3m 45s | 40% | - 1m 46s * | 21% |
| Southbound | - 4m 18s | 46% | - 3m 21s | 41% |
* Value may be low due to signal timings at Sheriffhall Roundabout.
Table A.6.4b: A68(T) Dalkeith Bypass - Travel Time Savings: Bypassed Route Through Dalkeith
| Direction | AM Peak | PM Peak | ||
|---|---|---|---|---|
| Time Savings (mins / secs) | % Saving | Time Savings (mins / secs) | % Saving | |
| Northbound | - 13s | 2% | + 14s | -3% |
| Southbound | - 1m 38s | 18% | - 34s | 7% |
The post opening savings in travel times presented in Table A.6.4a indicate the following travel time savings between Fordel Mains and Sheriffhall Roundabout for vehicles using the A68(T) Dalkeith Bypass:
- savings of around 3.5 minutes and 2 minutes during the AM and PM peak periods respectively in the northbound direction of travel; and
- savings of around 4 minutes and 3.5 minutes during the AM and PM peak periods respectively in the southbound direction of travel.
The travel time savings presented in Table A.6.4b indicate that pre and post opening travel times on the bypassed route through Dalkeith are broadly consistent.
Comparison Between Predicted and Actual Travel Times
The available predicted 2011 AM peak journey times have been compared with the post opening journey times collected in March 2012. The comparison between the available predicted and actual journey times indicates that:
- predicted AM peak journey times on the A68(T) Dalkeith Bypass, between Fordel Mains and the A720(T) Edinburgh City Bypass, were consistent with actual journey times in both directions of travel ;
- predicted AM peak journey times on the A720(T) Edinburgh City Bypass, between Sheriffhall Roundabout and the A68(T) Dalkeith Bypass, were significantly longer than the actual journey times in both directions of travel; and
- predicted AM peak journey times on the bypassed route through Dalkeith, between Fordel Mains and Sheriffhall Roundabout, were broadly consistent with the actual journey times in both directions of travel.
The predicted AM peak journey times may be significantly longer than actual times on the A720(T) Edinburgh City Bypass due to improvements implemented at Sheriffhall Roundabout in 2008 that were not considered as part of the modelling.
Review of Environmental Mitigation Measures
The environmental mitigation measures originally proposed for the A68(T) Dalkeith Bypass project were obtained from the project's Environmental Statement.
A review of the environmental mitigation measures was carried out in March 2011, which confirmed that the majority of measures committed within the Environmental Statement were in place and were providing appropriate levels of mitigation. The key mitigation measures implemented as part of the project are as follows:
- use of the existing landscape and topography to fit the project into the wider landscape;
- noise mitigation measures within the vicinity of Smeaton Burn;
- Sustainable Urban Drainage Systems (SUDS);
- hedgerow and woodland planting; and
- specific measures for the protection of mammals including badgers and otters.
As part of the review the following areas were identified that require maintenance:
- gaps beneath the acoustic barrier at Smeaton Burn;
- mammal fencing along the route; and
- the hedgerow planting at Fordel Mains.
Noise and Air Quality
The comparison between pre and post opening traffic flows within the study area (discussed in Section A.6.2) indicates that post opening traffic volumes through Dalkeith town are significantly lower, which will have reduced local noise levels and improved air quality.
Noise surveys were undertaken for the A68(T) Dalkeith Bypass project between January and March 2009 to assess the level of noise impact on properties within the vicinity of the bypass and to establish whether any noise insulation measures were required.
The survey indicated that, of the twenty-one properties identified as potentially being subject to changes in noise levels as a result of the project, fourteen properties had experienced a reduction in ambient noise levels with five properties having experienced a slight to moderate increase in ambient noise levels, however, the increase in noise was within the acceptable limits.
Two properties experienced substantial increases in ambient noise levels and an acoustic barrier was provided to limit the impact of this increase. As a result, the recorded increase in noise was within the acceptable limits.
The survey also indicated that none of the properties identified satisfied the criteria where noise insulation compensation would be required.
Environment: Key Findings
The review of the mitigation measures implemented for the A68(T) Dalkeith Bypass project confirmed that the majority of mitigation measures committed within the Environmental Statement were in place.
Whilst areas were identified that require maintenance, the project is considered to fit well within the existing open landscape.
Mitigation measures to reduce the impact of increased levels of noise within the vicinity of the bypass were implemented and are operating successfully.
Accidents
Comparison Between Pre and Post Opening Personal Injury Accident Numbers
The locations and severities of personal injury accidents occurring within the vicinity of the A68(T) Dalkeith Bypass project 3 years before and 1 year after project completion are shown in Figures A.6b and A.6c.
A summary of the personal injury accident data is shown in Table A.6.5.
Table A.6.5: A68(T) Dalkeith Bypass - Personal Injury Accident Data Summary
| Period | Fatal | Serious | Slight | Total Accidents |
|---|---|---|---|---|
| 3 Years Before | ||||
| A68(T) | 0 | 9 | 48 | 57 |
| 1 Year After | ||||
| A68(T) | 0 | 1 | 1 | 2 |
| Bypassed Route | 0 | 1 | 12 | 13 |
| Total | 0 | 2 | 13 | 15 |
As can be seen in Table A.6.5, two personal injury accidents (one serious and one slight) occurred on the A68(T) Dalkeith Bypass in the 1 year period following the opening of the project. In addition, thirteen personal injury accidents (one serious and twelve slight) occurred on the bypassed route through Dalkeith, resulting in a total of fifteen personal injury accidents (two serious and thirteen slight) occurring in the 1 year period following the opening of the project. This is in comparison to fifty-seven personal injury accidents (nine serious and forty-eight slight) in the 3 years before opening, which indicates a reduction in the number and severity of personal injury accidents occurring post opening of the project.
Road Safety Audits
The Stage 4 Road Safety Audit (RSA) was carried out in June 2010 and examines the accidents which occurred on the bypass and in the vicinity of the tie-ins to the existing road network during the period 1st January 2009 to 31st December 2009. This period differs with the summary of pre and post opening accidents presented in Table A.6.5, which covers the 1 year period following the opening of the project from 23rd September 2008 to 22nd September 2009.
Figure A.6b A68(T) Dalkeith Bypass
Figure A.6c A68(T) Dalkeith Bypass
The RSA report indicates that three personal injury accidents (one serious and two slight) occurred on the A68(T) Dalkeith Bypass, one personal injury accident (slight) occurred on a section of realigned local road and a further four personal injury accidents (slight) occurred on the A720(T) Edinburgh City Bypass, near to its junction with the A68(T).
The RSA report notes that two of the three personal injury accidents which occurred on the A68(T) Dalkeith Bypass involved vehicles performing u-turn manoeuvres and the remedial works undertaken at the Fordel Mains junction in March 2010 should address the issue.
The report also notes evidence of recent accidents which may have been unreported non-injury accidents or may have occurred outwith the period examined.
The RSA report concludes that the recorded accident records on the A68(T), A720(T) and local road network within the vicinity of the project did not highlight any common accident factors and that there was no further evidence of an accident problem that warranted further engineering work.
Safety: Key Findings
An assessment of the 1 year post opening personal injury accidents and a review of the Stage 4 RSA report, suggests that the A68(T) Dalkeith Bypass project is operating safely.
Transport Economic Efficiency
The decision to proceed with the project was based on the assumption that there would be a full closure of the High Street in Dalkeith, which was in line with the proposals of Midlothian Council at that time. Subsequent to public consultation by the council, the implemented measures included public realm enhancements and traffic calming measures, while maintaining a through route for traffic.
As noted above, for the purposes of evaluation, the predicted traffic flows and journey times are those from the model developed during the preparation of the project which best reflects the improvements that were implemented within Dalkeith town centre. This model predicted economic benefits that did not outweigh the cost of the project.
The comparisons of predicted and actual traffic flows and travel times, presented in section A.6.2, can be considered a proxy for whether the predicted economic benefits of the project are likely to be realised.
Comparison Between Predicted and Actual Traffic Flows
The comparison between predicted and actual traffic flows indicates that the predicted 2009 flows were within 3% of the observed 2009 flows on the Dalkeith Bypass, which is well within accepted limits.
Comparison Between Predicted and Actual Travel Times
The comparison between predicted and actual travel times indicates that the predicted journey times on the A68(T) Dalkeith Bypass are longer than the average observed journey times on some sections of the routes within the study area.
Economy: Key Findings
The comparison of predicated and actual traffic flows and journey times confirms that the predicted economic benefits from the model that best reflects the improvements that were implemented within Dalkeith town centre may be exceeded.
Investment Costs
Comparison Between Predicted and Out-turn Costs
The out-turn and predicted project costs are shown in Table A.6.6.
Table A.6.6: A68(T) Dalkeith Bypass - Project Cost Summary
| Out-turn Cost | Predicted Cost | Difference (Out-turn - Pred.) | |||
|---|---|---|---|---|---|
| @ April 10 |
Mid 02 Prices in 2002 at 3.5% Discount |
Q3 05 Prices |
Mid 02 Prices in 2002 at 3.5% Discount |
Mid 02 Prices in 2002 at 3.5% Discount |
|
| Total | £40,605,719 | £29,421,520 | £33,394,000 | £26,480,007 |
£2,941,512 (11%) |
Cost to Government: Key Findings
The out-turn cost of the A68(T) Dalkeith Bypass project is approximately £2.9m (11%) greater than was predicted cost at the time of assessment.
Initial Indications
The economic appraisal results from the model developed during the preparation of the project, which best reflects the improvements that were implemented within Dalkeith town centre, predicted a Net Present Value (NPV) of -£4.42m and Benefit to Cost Ratio (BCR) of 0.88.
Based on the comparisons presented in sections A.6.5 and A.6.6, which confirm that the predicted economic benefits from this model may have been underestimated and indicate that the cost is greater than predicted, the NPV and BCR of the project may be greater than expected.
Value for Money: Key Findings
The NPV and BCR relating to the alternate model (which better reflects the improvements that were implemented within Dalkeith town centre) may be greater than predicted at the time of assessment.
This will not have affected the decision to proceed with the project as the main model developed during the preparation of the project (which reflected current thinking at the time in regards to improvements within Dalkeith) would have continued to provide value for money.
A.6.8 Achievement of Objectives
As specific indicators to measure the performance of the A68(T) Dalkeith Bypass project against its objectives have not been developed, an initial indication of how the project is progressing towards achieving its objectives is based on the pre opening data available, supplemented by post opening data collected as part of the evaluation.
Initial Indications
A summary of the evaluation, providing an indication of how the A68(T) Dalkeith Bypass project is progressing towards achieving its objectives, is presented in Table A.6.7.
Table A.6.7: A68(T) Dalkeith Bypass - Progress Towards Achieving Objectives
| Objective | Commentary | Progress | |||
|---|---|---|---|---|---|
| To provide good quick and reliable inter-urban road links. | Average journey times for strategic traffic using the A68(T) Dalkeith Bypass in both directions of travel have reduced significantly in the peak periods as a result of the project. | +ve | |||
| To improve accessibility from Edinburgh to the Central Borders and the North of England. | The significant reduction in average journey times for strategic traffic using the A68(T) Dalkeith Bypass support the conclusion that the project has contributed towards an improvement in accessibility from Edinburgh to the Borders and the North of England. | +ve | |||
| To aid economic prosperity and development by reducing travel costs particularly for business and commercial traffic serving existing and proposed business and commercial developments (including tourism and service industries). | The project reduces journey times for strategic road users, providing travel cost benefits to transport users, which is expected to help encourage economic development within the Lothian, Borders and wider area. | +ve | |||
| To improve road safety and contribute towards the Government's overall target of reducing road casualties. | A comparison between 3 years before opening and 1 year after opening personal injury accidents occurring within the vicincity of the project indicates that 57 accidents (9 serious and 48 slight) occurred prior to the opening of the project in comparison to 15 accidents (2 serious and 13 slight) occuring in the 1 year period following the opening of the project suggesings that the project is operating safely and that the bypass is safer than the bypassed route. | +ve | |||
| To minimise the intrusion of roads and traffic on communities and on the environment. | Environmental and landscaping measures have been implemented to help the project fit within the existing open landscape. | +ve | |||
| To use the limited resources available as effectively as possible to achieve good value for money for both taxpayers and transport users. | As a result of the improvements in Dalkeith town centre that were implemented subsequent to public consultation, the full economic benefits of the project as anticipated during its preparation are unlikely to be realised. | = | |||
Key:
+ve Initial indication(s) that objective may be achieved
= Progress towards achievement of objective cannot be confirmed
O Initial indication(s) that objective may not be achieved