Introduction
Introduction
Background to Project Evaluation
Road infrastructure projects normally take a minimum of 5 to 7 years to plan prior to the commencement of construction. It is not possible to know exactly what will happen when a project is opened, nor what would have happened had the project not been built. This is particularly applicable when the project is opened a number of years after its original assessment.
The aims of evaluation, as 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’, 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.
The evaluation of trunk road projects is evolving as Transport Scotland improves its process and reporting to reflect the principles of monitoring and evaluation set out in the Scottish Transport Appraisal Guidance (STAG).
STAG advocates evaluation against indicators and targets derived for the Transport Planning Objectives (TPOs) originally set for the project, STAG criteria (Environment, Safety, Economy, Integration and Accessibility and Social Inclusion) and relevant policy directives, the aim of which is to identify:
- Whether the project is performing as originally intended;
- Whether, and to what extent, it is contributing to established policy directives; and
- Whether the implemented project continues to represent value for money.
Furthermore, Scottish Trunk Road Infrastructure Project Evaluation (STRIPE) by Transport Scotland sets out the requirements for evaluation which draws on DMRB and STAG. This document was finalised in 2013 and acts as a guide to evaluation for relevant projects. STRIPE states that two programmed evaluations should be carried out on relevant schemes, as follows:
- A 1YA Evaluation – prepared one year after opening, this report should “provide Transport Scotland with an early indication (as far as is practicable) that the project is operating as planned and is on-track to achieve its objectives. The 1YA evaluation also provides a Process Evaluation including an assessment of actual vs. forecast project cost and programme together with reasons for variance”. STRIPE also states that a stand-alone report should be prepared on each individual project. Information gathering should be supported by a site visit and stakeholder interviews.
- A Detailed Evaluation – undertaken 3 and / or 5 years after opening. This second evaluation “considers a project’s impacts, whether it has achieved its objectives and reviews the actual impacts against forecasts and determines the causes of any variances”.
Evaluation Reporting
As recommended in STRIPE, this report constitutes a 1YA Evaluation Report. It is a standalone report on the M8 M73 M74 Motorway Improvements Project. This project fits the criteria for evaluation at this stage, as a major infrastructure project. Table 1 summarises the characteristics of the project. The location of the project is presented in Figure 1.
Route | Project Name | Standard | Length (km) | Open to Traffic |
M8 | Baillieston to Newhouse | D2 / D3 / D4 Motorway | 12 | 30 April 2017 |
A725 | Raith Junction | Junction Improvement | 1.8 | 16 February 2017 |
M8 / M73 / M74 | Associated Network Improvements | D3 / D4 Motorway | 13 (Combined distance of additional lanes provided on M8 / M73 / M74) | 1 June 2017 |

Project extents on M8 from Baillieston to Newhouse, M74 from Cambuslang to Hamilton, and M73 from Uddingston to Mollinsburn.
< Previous | Contents | Next >