Transport Scotland Scottish Trunk Road Infrastructure Project Evaluation Evaluation Report for Trunk Road Projects Opened between April 07 and March 09
4 Key Findings
This chapter provides a summary of the key findings from the evaluations undertaken for the ten trunk road infrastructure projects that opened between April 07 and March 09, highlighting any trends and stand-out issues.
- The evaluations undertaken indicate that the projects are generally operating as expected.
- The standards of carriageway constructed are appropriate.
- The available survey information for projects that increase overtaking opportunities on the A75(T), A76(T) and A77(T) routes indicates that, in the direction of the dedicated overtaking opportunity, these projects have facilitated safe overtaking opportunities, the dispersal of vehicles in platoon and generally improve travel times. In the direction of restricted overtaking, the impact on platooning and travel times can be negative.
- Predicted traffic flows for bypass projects, which are commonly estimated using wide area traffic models, can vary significantly from actual flow levels due to the complex interaction between transport and land use.
- Whilst there appears to be a general bias towards the over prediction of traffic flows for carriageway improvement projects that opened between April 07 and March 09 (due to the economic downturn, changes in Sea Ferry operations, etc.), predicted flows are (with a few exceptions) within accepted limits, which suggests that the forecasting techniques used for appraising these types of projects are generally appropriate.
- A review of the proposed mitigation measures contained in the environmental reports for each of the projects opened between April 07 and March 09 confirmed that the majority of measures committed within the Environmental Statement were in place and were providing appropriate levels of mitigation.
- Whilst some mitigation measures were not evident on site, these may be due to variations and/or separate arrangements with the relevant landowners. Transport Scotland is looking at ways to improve the environmental review process to provide a better record of the mitigation measures that have been implemented, including details of any agreed variations.
- Areas that require maintenance were identified as part of the environmental mitigation measures review undertaken for A68(T) Dalkeith project.
- Initial indications from the available personal injury accident data are that the projects opened between April 07 and March 09 are contributing towards an overall improvement in road safety.
- Stage 4 RSA reports for projects that opened between April 07 and March 09 have (with one exception) been available and provide evidence supporting this apparent improvement in road safety.
- One slight accident occurred on the A77(T) Glen App project during the 1 year period following project opening compared with no personal injury accidents in the 3 years before opening, although a review of the personal injury accident data suggests that the accident was not attributable to the design or layout of the project.
- The RSA for the A75(T) Planting End to Drumflower project raises concerns over vehicle speeds, although there is no evidence to suggest that the project is not operating safely.
- As a result of the general bias towards the over prediction of traffic flows for projects that opened between April 07 and March 09, the economic benefits of a number of projects may have been overestimated.
- The over prediction of economic benefits due to external factors that could not readily have been seen at the time of the assessments supports the need for appropriate sensitivity testing to understand the range of possible economic outcomes.
- The projects evaluated against the Integration criteria generally support Local and Central Government policy.
- A review of the proposed measures for cyclists and pedestrians indicates that the measures are generally being delivered.
- The projects (particularly bypass projects) provide lower journey times for public transport.
- The bypass projects provide an alternative to the bypassed routes, which has resulted in improvements to pedestrian accessibility in town centres.
- There appears to be a slight bias towards the under prediction of project costs for projects that opened between April 07 and March 09.
- Whilst the overall total cost of projects evaluated using a 1998 present value year were under predicted, the overall total cost of projects evaluated using a 2002 present value year were overestimated by a similar amount.
- Based on the evaluation of economic benefits and project costs, the value for money associated with a number of projects that opened between April 07 and March 09 are unlikely to be as great as predicted, although it is judged that they will continue to provide a benefit to road users.
- The majority of objectives for projects that opened between April 07 and March 09 have not been expressed with SMART (Specific, Measurable, Attainable, Relevant and Timed) principles in mind having been set prior to the publication of the Scottish Transport Appraisal Guidance (STAG).
- The majority of objectives where progress could not be confirmed relate to Value for Money. It is not always possible to confirm whether projects are likely to deliver value for money at an early stage after opening for a number of reasons, which may include uncertainty regarding future traffic flow trends, the magnitude of benefits attributable to after opening traffic conditions, etc.
- Overall, the projects that opened between April 07 and March 09 are generally progressing towards achieving their objectives.