Transport Scotland Trunk Road Project Evaluation - Report for Trunk Road Projects Opened between April 05 and March 07
The aims of Project Evaluation for trunk roads reflect those set out in the Design Manual for Roads and Bridges (DMRB), Volume 5, SH 1/97 'Traffic and Economic Assessment of Road Schemes in Scotland'. These are as follows:
- to satisfy the demands of good management and public accountability by providing the answers to questions about the effects of a new or improved road;
- to identify the strengths and weaknesses in the techniques used for appraising projects, so that confidence in the roads programme is maintained;
- to allow the predictive ability of the traffic or transport models used to be monitored to establish whether any particular form of model is consistently more reliable than others when applied to particular types of projects; and
- to assist in the assessment of compensation under Part 1 of the Land Compensation (Scotland) Act 1973 for depreciation due to the physical factors caused by the use of public works.
Transport Scotland currently undertakes a reporting system of 'Project Evaluation' for all trunk road projects costing over £5m. This compares the:
- traffic flows resulting from the implementation of a trunk road project with those predicted during the project's preparation;
- carriageway standard provided with that required by observed flows;
- estimated project cost with the actual out-turn cost;
- accident statistics before and after project opening; and
- environmental mitigation measures put forward in the project's Environmental Statement with those actually included as part of the project's construction.
With the exception of the environmental mitigation measures, these comparisons are undertaken as proxies for the economic performance of the project as the time and resource implications of re-running full economic assessments with actual costs, traffic flows and accidents for all projects would be excessive. The evaluation of the environmental mitigation measures monitors the implementation and success of the measures proposed within the original Environmental Statement.
The Evaluation Report for Trunk Road Projects Opened between April 05 and March 07 presents the evaluation undertaken for projects completed and opened to traffic in the 2005/06 and 2006/07 financial years.
The projects evaluated in this report are listed in Table 1.1 and their locations are shown in Figure 1.1.