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
A.5 A9(T) HELMSDALE PHASE 2
Project Overview
Improvements to the A9(T) between Helmsdale and the Ord of Caithness were carried out in two phases.
The Phase 1 improvements were largely on-line and involved the construction of 2.5 kilometres of 7.3 metre-wide single carriageway and included the provision of a 515 metre-long, 10 metre-wide section of climbing lane for northbound traffic to the north of the Phase 2 works.
The Phase 2 improvements were largely off-line and involved the construction of 2.1 kilometres of 6 metre-wide single carriageway and a 280 metre-long, 10 metre-wide section of climbing lane for northbound traffic at the northern extent of the project to tie into the Phase 1 works.
The general location of the project is shown in Figure A.5a.
The A9(T) Helmsdale Phase 2 project was officially opened to traffic on 21st August 2008.
Project Objectives
The objectives of the A9(T) Helmsdale Phase 2 project were set as follows:
- to improve safety on the A9(T);
- to improve through movement of traffic on the A9(T);
- to minimise environmental impact;
- to be promotable to the local community;
- to minimise disruption during construction; and
- to be maintainable and operable.
Evaluation Methodology
The A9(T) Helmsdale Phase 2 project has been evaluated against the above objectives and the following criteria:
- Environment;
- Safety;
- Economy;
- Costs to Government; and
- Value for Money.
Figure A.5a A9(T) Helmsdale Phase 2
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.
A.5.2 Network Traffic Indicators
Traffic Volumes
The location of Transport Scotland's Automatic Traffic Counter (ATC) within the study area is shown in Figure A.5a.
Traffic counter JTC08226 was superseded by 104890 in 2007 which provided a more detailed classification of vehicles using the A9(T) at Berriedale.
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.5.1.
Table A.5.1: A9(T) Helmsdale Phase 2 - ATC Data
| ATC Reference | AADT by Year | |||||
|---|---|---|---|---|---|---|
| 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | |
| A9(T) at Berriedale | ||||||
| JTC08226 / 104890 | 1,950 | 1,953 | 2,068 | Year of Opening | 2,084 | 1,936 |
A comparison between pre and post opening traffic volumes on the A9(T) at Berriedale indicates that traffic flows in 2009 were consistent with 2007 flow levels, however, traffic flows between 2009 and 2010 have reduced marginally by around 100 vehicles per day (vpd), approximately 7%.
Given the nature of the A9(T) Helmsdale Phase 2 project, changes in post opening traffic levels are not likely to be as a consequence of changes to the carriageway standard and may be as a result of reductions in traffic volumes across the wider trunk road network due to the economic downturn experienced during the evaluation period.
Comparison Between Predicted and Actual Traffic Flows
The opening year flow comparisons for the A9(T) Helmsdale Phase 2 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 counter within the study area.
As part of the project's appraisal, National Road Traffic Forecasts (NRTF) low and high growth factors were applied to the observed 2002 base year traffic flows to derive opening and future modelled assessment year traffic flows.
Predicted traffic flows for 2009 were derived by factoring the 2007 opening year flows used in the economic assessment with NRTF 97 low and high growth factors.
A summary of the actual and predicted traffic data is shown in Table A.5.2 below.
Table A.5.2: A9(T) Helmsdale Phase 2 - Traffic Analysis Summary
|
ATC Ref |
Actual AADT* | Predicted AADT |
% Difference (Predicted - Actual) / Actual |
||
|---|---|---|---|---|---|
| Low | High | Low | High | ||
| A9(T) at Berriedale | |||||
| 104890 | 2,084 | 1,904 | 1,977 | -8.6% | -5.1% |
* 2009 flows (first full year of ATC data available)
The comparison between predicted and actual AADT flows in Table A.5.2 indicates that the predicted 2009 flow was 8.6% and 5.1% lower than the observed 2009 flow under low and high traffic forecast scenarios respectively.
Whilst this comparison indicates that actual traffic growth has exceeded the NRTF low and high growth factors used within the economic assessment, the difference is within the accepted limits.
Carriageway Standard Assessment
A single 2-lane carriageway with a climbing lane (tying into the existing climbing lane that was constructed as part of the Phase 1 works) was constructed on the A9(T), north of Helmsdale, improving the alignment of the route and providing dedicated overtaking opportunities to help reduce accident numbers, 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.5.3 based on the observed 2009 traffic flow.
Table A.5.3: A9(T) Helmsdale Phase 2 - Assessment of Carriageway Standard (TA 46/97)
| Opening Year AADT* | TA 46/97 Standard | Constructed Standard |
|---|---|---|
| 2,084 | 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 the surrounding topography and the existing climbing lane constructed as part of a previous improvement, the constructed carriageway standards are considered appropriate.
Travel Times
Change in Travel Times
As the Helmsdale Phase 2 project has extended the climbing lane and resulted in a significant reduction in the overall length of the A9(T) route (by approximately 1 kilometre), it can be expected that journey times on the A9(T), over the extent of the project are highly likely to have reduced.
Review of Environmental Mitigation Measures
The environmental mitigation measures originally proposed for the A9(T) Helmsdale Phase 2 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 the A9(T) Helmsdale Phase 2 project has resulted in a significant reduction in the overall length of the A9(T) route, it is likely that the overall impact of noise and air quality over the extents of the project will have reduced.
Given the rural nature of the A9(T) Helmsdale Phase 2 improvements, no significant impact on noise and air quality is expected. It is therefore not appropriate to evaluate the project's impact on noise and air quality.
Environment: Key Findings
The review of mitigation measures implemented for the A9(T) Helmsdale Phase 2 project confirmed that the majority of measures committed within the Environmental Statement were in place. Whilst some variations from the proposed mitigation measures had been identified, these were not considered to have had a material detrimental impact on the general integration of the project into its surrounding.
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 A9(T) Helmsdale Phase 2 project 3 years before and 1 year after project completion are shown in Figures A.5b and A.5c.
A summary of the personal injury accident data is shown in Table A.5.4.
Table A.5.4: A9(T) Helmsdale Phase 2 - Personal Injury Accident Data Summary
| Period | Fatal | Serious | Slight | Total Accidents |
|---|---|---|---|---|
| 3 Years Before | ||||
| A9(T) | 0 | 2 | 3 | 5 |
| 1 Year After | ||||
| A9(T) | 0 | 0 | 1 | 1 |
| Bypassed Sections | 0 | 0 | 0 | 0 |
As can be seen in Table A.5.4, one personal injury accident (slight) occurred in the 1 year period following the opening of the project in comparison to five personal injury accidents (two serious and three slight) 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 November 2010. The RSA report confirmed that only one personal injury accident (slight) occurred during the period 1 year after project opening and involved a cyclist travelling southbound on a downhill section. The RSA report also noted that the cyclist may simply have been travelling too fast resulting in a loss of control.
Figure A.5b A9(T) Helmsdale Phase 2
Figure A.5c A9(T) Helmsdale Phase 2
The report concluded that the safety record over the length of the project has improved significantly following the opening of the project and given the singular nature of the accident involving a single cyclist, there is no common factor or trends.
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) Helmsdale Phase 2 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.5.2, 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 up to 8.6% lower than the observed 2009 flow on the A9(T), which may have resulted in an underestimation of the road user benefits of the project.
Economy: Key Findings
The difference between predicted and actual AADT flows is likely to have resulted in an underestimation of road user benefits.
Investment Costs
Comparison Between Predicted and Out-turn Costs
The out-turn and predicted project costs are shown in Table A.5.5.
Table A.5.5: A9(T) Helmsdale Phase 2 - Project Cost Summary
| Out-turn Cost | Predicted Cost | Difference (Out-turn - Pred) | |||
|---|---|---|---|---|---|
| @ April 10 |
Mid 98 Prices in 1998 at 3.5% Discount |
Q2 04 Prices |
Mid 98 Prices in 1998 at 3.5% Discount |
Mid 98 Prices in 1998 at 3.5% Discount |
|
| Total | £7,108,640 | £4,003,546 | £6,116,158 | £4,070,280 |
-£66,734 (2%) |
Cost to Government: Key Findings
The out-turn cost of the A9(T) Helmsdale Phase 2 project is around £0.1m (2%) lower than was predicted at the time of assessment.
Initial Indications
The economic appraisal results for the A9(T) Helmsdale project predicted a Net Present Value (NPV) of £2.27m and Benefit to Cost Ratio (BCR) of 1.65 based on an average of the results from the economic assessments carried out under NRTF low and high traffic scenarios.
Based on the comparisons presented in sections A.5.5 and A.5.6, which suggest that the benefits are likely to have been underestimated and indicate that the cost is marginally lower than predicted, the NPV and BCR of the project is likely to be greater than predicted.
Value for Money: Key Findings
It is judged that the project is likely to deliver value for money over and above that predicted as part of the project's assessment.
A.5.8 Achievement of Objectives
As specific indicators to measure the performance of the A9(T) Helmsdale 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 A9(T) Helmsdale Phase 2 project is progressing towards achieving its objectives, is presented in Table A.5.6.
Table A.5.6: A9(T) Helmsdale Phase 2 - Progress Towards Achieving Objectives
| Objective | Commentary | Progress | |||
|---|---|---|---|---|---|
| Improve safety on the A9(T). | A comparison between 3 years before opening and 1 year after opening personal injury accidents occurring within the vicincity of the project indicates that 5 accidents (2 serious and 3 slight) occurred prior to the opening of the project in comparison to 1 personal injury accident (slight) occuring in the 1 year period following the opening of the project suggesting an improvement in road safety. | +ve | |||
| Improve through movement of traffic on the A9(T). | Although pre and post opening journey time surveys have not been carried out for the A9(T) Helmsdale Phase 2 Improvements (and, therefore, actual changes in vehicle speeds and journey times can not be quantified), it can be expected that, as a result of the significant improvements in vertical and horizontal geometry shortening the route, any impacts on vehicle speeds and journey times are likely to be positive. | +ve | |||
| Minimise environmental impact. |
No significant adverse environmental impacts were identified during the site visit. Changes to the design of the project occurred between the publishing of the Environmental Statement and the as-built project, however, these changes are not deemed to have resulted in a detrimental effect on the integration of the project into the wider landscape or upon receptors surrounding the A9(T) route, the use of the existing landform and the provision of new planting along the length of the route helps to create a 'visual fit' within the wider landscape whilst still maintaining open views to the east. |
+ve | |||
| Be promotable to the local community. | During the public consultation exercise undertaken during the development and selection of the preferred scheme, the alignment adopted was favoured by 87% of respondents. | +ve | |||
| Minimise disruption during construction. | Controls / conditions were imposed through the contract to minimise disruption and these were monitored during construction. | +ve | |||
| Be maintainable and operable. | Whilst there are a few local maintenance issues, the project can generally be considered to be maintainable and operable. | +ve | |||
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