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
The project involved the construction of a grade separated junction, including two new slip roads on the western side of the A9(T) at Ballinluig and improvements to the A9(T) carriageway, which enabled the removal of the temporary 50mph speed limit within the vicinity of the junction.
The general location of the project is shown in Figure A.4a.
The A9(T) Ballinluig Junction Improvement was officially opened to traffic on 26th May 2008.
The objectives of the A9(T) Ballinluig Junction Improvement project were set as follows:
- to contribute to Government Safety Objectives for the reduction of fatal and serious accidents of 40% by 2010;
- to achieve good value for money;
- to maintain through movement on A9(T);
- to be able to be maintained and operated safely;
- to minimise disruption during construction;
- to incorporate measures for non motorised users;
- to avoid impacts on environmentally designated areas (Special Area of Conservation (SAC) and Site of Special Scientific Interest (SSSI));
- to minimise environmental impact; and
- to be consistent with local planning objectives and policies.
The A9(T) Ballinluig Junction Improvement project has been evaluated against the above objectives and the following criteria:
- Accessibility & Social Inclusion;
- Costs to Government; and
- Value for Money.
The evaluation is supported by the consideration of network traffic indicators, including traffic volumes and travel times presented in the following section.
The locations of Automatic Traffic Counters (ATCs) within the study area are shown in Figure A.4a.
Traffic counters ATC03021 and JTC00500 both experienced operational issues during the period 2006 to 2011. As such, to provide a robust assessment, traffic flows for 2006 and 2007 have been derived from ATC03021 and traffic flows for 2009 to 2011 have been derived from JTC00500.
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.4.1.
|ATC Reference||AADT by Year|
|ATC03021 / JTC00500||13,559||13,849||Year of Opening||13,705||13,463||13,311|
|A827 West of Ballinluig Junction|
|JTC00141||3,092||3,085||Year of Opening||3,165||3,319||3,066|
A comparison between pre and post opening traffic volumes on the A9(T) mainline indicates that traffic flows in 2009 were around 150 vehicles per day (vpd) (approximately 1%) lower than 2007 flow levels. Over the same period, traffic flows on the A827 west of Ballinluig junction have seen a marginal increase of approximately 100 vpd or 3%.
The comparison also indicates that traffic flows on the A9(T) mainline have decreased with annual reductions of approximately 150 vpd to 250 vpd (1% to 2%) between 2009 and 2011. Traffic flows along the A827 west of Ballinluig junction increased by approximately 150 vpd (around 5%) between 2009 and 2010 and decreased by approximately 250 vpd (8%) between 2010 and 2011.
Given the nature of the A9(T) Ballinluig Junction Improvement project, changes in traffic levels are not likely to be as a consequence of changes to the junction layout and carriageway.
Comparison Between Predicted and Actual Traffic Flows
The opening year flow comparisons for the A9(T) Ballinluig Junction Improvement project are based on AADT flows from 2009 as this was the first full year of reliable traffic data available from Transport Scotland's traffic counter within the study area.
As part of the project's appraisal, National Road Traffic Forecasts (NRTF) central growth factors were applied to the observed 2004 base year traffic flows to derive opening and future modelled assessment year traffic flows.
Predicted traffic flows for 2009 were derived by factoring the 2004 base year flows used in the economic assessment with NRTF 97 central growth factors.
A summary of the actual and the predicted traffic data is shown in Table A.4.2 below.
|Actual AADT*||Predicted AADT||
(Predicted - Actual) / Actual
* 2009 flows (first full year of ATC data available)
The comparison between predicted and actual AADT flows in Table A.4.2 indicates that the predicted 2009 flow is 7.3% lower than the observed 2009 flow, which is within accepted limits.
Carriageway Standard Assessment
Whilst the 2-lane carriageway section on the A9(T) at Ballinluig was extended south as part of the Ballinluig Junction Improvement project, the works principally involved the construction of a new grade separated junction, therefore, it has not been necessary to carry out a carriageway standard assessment.
Change in Travel Times
As a result of the grade separated junction on the A9(T) which facilitates the through movement of traffic, the temporary 50mph speed limit enforced on the A9(T) within the vicinity of the junction has been removed. Whilst journey times have not been measured, it can be expected that journey times on the A9(T) will have reduced.
Review of Environmental Mitigation Measures
The environmental mitigation measures originally proposed for the A9(T) Ballinluig Junction Improvement project were obtained from the project's Environmental Statement.
A review of the environmental mitigation measures was carried out in May 2010, which confirmed that the majority of measures committed within the Environmental Statement were in place and were providing appropriate levels of mitigation.
Noise and Air Quality
As no significant impact on noise and air quality is expected as a result of the A9(T) Ballinluig Junction Improvement project, it is not appropriate to evaluate the project's impact on noise and air quality.
Environment: Key Findings
The review of the mitigation measures implemented for the A9(T) Ballinluig Junction improvement project indicated that, overall, the mitigation had been successful, particularly the provision of ecological mitigation and the integration of many of the engineering works into the landscape when viewed from Ballinluig Village.
Comparison Between Pre and Post Opening Personal Injury Accident Numbers
The locations and severities of personal injury accidents occurring within the vicinity of the A9(T) Ballinluig Junction Improvement project 3 years before and 1 year after project completion are shown in Figures A.4b and A.4c.
A summary of the personal injury accident data is shown in Table A.4.3.
|3 Years Before|
|1 Year After|
As can be seen in Table A.4.3, no personal injury accidents have occurred in the 1 year period following the opening of the project in comparison to three personal injury accidents (one fatal and two serious) in the 3 years before opening, suggesting a potential improvement in road safety.
Road Safety Audits
The Stage 4 Road Safety Audit (RSA) was carried out in June 2009. The RSA report confirmed that no personal injury accidents had occurred within the vicinity of the project within the 1 year period after opening. The report, however, did note that there was evidence of an accident occurring on the southbound entry to Ballinluig Village but no record of this accident had been received.
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 A9(T) Ballinluig project is operating safely.
Transport Economic Efficiency
Comparison Between Predicted and Actual Traffic Flows
The comparison of predicted and actual traffic flows, presented in section A.4.2, can be considered a proxy for whether the predicted economic benefits of the project are likely to be realised.
The comparison indicates that the predicted 2009 flow was 7.3% lower than the observed 2009 flow on the A9(T). The project may, therefore, deliver additional benefits to road users than those predicted as part of the project's appraisal.
Economy: Key Findings
The difference between predicted and actual AADT flows is likely to have resulted in an underestimation of road user benefits.
The Local Plan relevant at the time that the project was progressed does not contain any Local Government policies specific to Ballinluig Junction, the project supports Central Government policy through its objective of reducing accidents.
Integration: Key Findings
The project contributes to Government Safety Objectives for the reduction of fatal and serious accidents.
The following observations, relevant to community accessibility, were made during the environmental mitigation site visit in May 2010.
To the east of the A9(T), provision has been made for cyclists within the local access road and through segregated cycleways incorporated into the project design. Signs are present along the access road denoting the presence of cyclists and the road also incorporates several passing places to allow for traffic to pass safely.
Accessibility & Social Inclusion: Key Findings
Observations from the environmental mitigation site visit indicate that the project incorporates measures for both cyclists and walkers.
Comparison Between Predicted and Out-turn Costs
The out-turn and predicted project costs are shown in Table A.4.4.
|Out-turn Cost||Predicted Cost||Difference (Out-turn - Pred)|
|@ April 10||
Mid 02 Prices in
2002 at 3.5% Discount
|July 05 Prices||
Mid 02 Prices in
2002 at 3.5% Discount
Mid 02 Prices in
2002 at 3.5% Discount
Cost to Government: Key Findings
The out-turn cost of the A9(T) Ballinluig project is approximately £2.1m (23%) greater than was predicted at the time of assessment.
The economic appraisal results for the A9(T) Ballinluig Junction Improvement project predicted a Net Present Value (NPV) of £9.92m and Benefit to Cost Ratio (BCR) of 1.95 under the NRTF central traffic forecast scenario.
Based on the comparisons presented in sections A.4.5 and A.4.8, which suggest that the benefits are likely to have been underestimated and indicate that the cost is greater than predicted, the NPV and BCR of the project are unlikely to be as great as predicted.
Value for Money: Key Findings
Although the NPV and BCR are unlikely to be as great as predicted at the time of assessment, it is judged that the project will continue to represent value for money.
As specific indicators to measure the performance of the A9(T) Ballinluig Junction Improvement 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.
A summary of the evaluation, providing an indication of how the A9(T) Ballinluig Junction Improvement project is progressing towards achieving its objectives, is presented in Table A.4.5.
|Contribute to Government safety objectives for the reduction of fatal and serious accidents of 40% by 2010||No personal injury accidents were recorded in the 1 year period following the opening of the project in comparison to 1 fatal and 2 serious accidents in the 3 years before opening suggesting an improvement in road safety.||+ve|
|Achieve good value for money||
The economic assessment undertaken for the project indicates that the Ballinluig Junction improvements could deliver significant travel time and accident reduction benefits to road users.
Whilst the out-turn costs were greater than the predicted project costs, a review of the economic assessment indicates that even with this increase the project would still have provided a benefit to road users and the project would continue to represent value for money.
|Maintain through movement on A9(T)||The new grade separated junction on the A9(T) facilitates the through movement of traffic through the removal of vehicles turning on the mainline. As the temporary 50mph speed limit on the A9(T) within the vicinity of the junction has been removed, journey times of through traffic are likely to have reduced.||+ve|
|Be able to be maintained and operated safely||A servitude right of access is available along the surfaced track to the south of the A9(T), beyond the trunk road boundary. Whilst there are a few local issues being addressed, the junction can generally be maintained and operated safely.||+ve|
|Minimise disruption during construction||
Controls / conditions were imposed through the contract to minimise disruption and these were monitored during construction.
The traffic management arrangement adopted to slow traffic through the works and provide access to Ballinluig village is considered to have worked well.
|Incorporate measures for non motorised users||Several measures were incorporated for non motorised users including a signed cycleway along the eastern access road, and dedicated cycleways and footpaths elsewhere within the project.||+ve|
|Avoid impacts on environmentally designated area (SAC and SSSI).||The site visit did not identify any significant impacts occurring to the SAC and SSSI, although no dedicated ecological surveys were undertaken. Cut-off lighting on the new roundabout adjacent to the River Tummel helps in minimising light affecting the interests of the designations.||+ve|
|Minimise environmental impact.||
The design of the project has helped to minimise the environmental impact.
The only residual impacts remaining are as a result of the materials and design of the wing walls and Network Rail safety barriers, which adversely affect views and also the quality of the planting on site.
|Be consistent with local planning objectives and policies.||The Local Plan relevant at the time that the project was progressed does not contain any Local Government policies specific to Ballinluig Junction.||=|
+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