Chamber and committees

Transport Scotland conducts machine-based surveys using specialist vehicles each year to gather information on the surface integrity of the road; the friction characteristics of the surface; and the structural capacity (strength) of the underlying road construction. The data obtained provides an annual snapshot of the road condition across the network and is used to determine a Road Condition Index for each section of road. The Index values can then be used to identify where detailed engineering investigations should be focused in order to determine maintenance requirements.

The proportion of the A90 that has been assessed as requiring further preliminary investigation to determine whether structural maintenance is required is currently 18%. This compares with 17% across the whole of the trunk road network.

There have been no official complaints logged regarding the overall condition of the A90 in the last five years. However, there has been a total of 171 individual complaints with resulting reports:

This information is not held by the Scottish Government. The member may wish to contact Network Rail.

Transport Scotland’s trunk road maintenance budget is not allocated on a route or part-route basis. It is distributed based upon need and prioritisation of schemes developed from regular inspections and condition surveys.

Please see below for maintenance spend for all trunk roads in the north east of Scotland over the last 5 full financial years.

Transport Scotland contracts for the management, maintenance and operation of the trunk road network contain highly prescriptive requirements to keep drainage assets working and trunk road traffic moving safely. For example, the contracts contain annual routine and cyclic maintenance requirements that are designed to ensure drainage assets are working and checked for deterioration. Transport Scotland contracts also contain requirements for Operating Companies to complete weekly driven inspections of all trunk roads to identify safety critical defects. If any are identified, they are required to address the issue or make it safe within set timescales. In addition to this, Transport Scotland's Operating Companies are required to maintain Disruption Risk Management Registers to identify vulnerable locations subject to frequent disruption. Where such sites are identified, the Operating Companies are required to investigate the issue and look to deliver solutions to improve journey time reliability.

I refer the member to the answer to question S6W-33187 on 23 January 2025. All answers to written Parliamentary Questions are available on the Parliament's website, the search facility for which can be found at https://www.parliament.scot/chamber-and-committees/written-questions-and-answers.

Transport Scotland’s trunk road maintenance budget is not allocated on a route or part-route basis. It is distributed based upon need and prioritisation of schemes developed from regular inspections and condition surveys.

Current best practice for the management of large infrastructure networks is set out in the international standard for the management of assets ISO 55001, which requires organisations to adopt a formal asset management approach. Transport Scotland is the first UK trunk road authority to reach this standard demonstrating that public funds are being spent in the most efficient and effective manner.

We have developed and implemented a formal value management process for roads structural maintenance schemes for assessing the benefits of undertaking maintenance and the associated risks of not undertaking maintenance. Each scheme in the one-year maintenance programme is scored against a range of criteria:

a. Safety – to maintain a safe network and assess the level of risk to the road user. Those schemes that are safety critical or have a high level of risk will have the highest priority scoring.

b. Journey Time Reliability – to assess the level of risk to the service, e.g. route availability.

c. Environment and Sustainability – to assess the impact of a scheme on the environment, noise reduction, carbon factor, recycling and sustainability.

d. Value for Money – to consider the economic efficiency of the scheme and seek to minimise the whole life costs (i.e. invest now to deliver savings later).

The scores are used to determine which schemes should remain in the current year and which can be deferred until the following year. This ensures that those parts of the network with the greatest need are addressed and that the available funds are allocated in a fair, objective and transparent manner.

The prioritisation of bridges and structures maintenance follows as similar process with a Value Management Risk Approach using the following four criteria:

a. Safety – the overall effects on the end user, including fatalities and injuries that would be caused by a failure.

b. Functionality – the impact of a loss or reduction in service. This may be considered at route, structure or component level.

c. Environment – Environmental impacts, such as pollution caused through traffic delay, the sensitivity of the route/area, etc.

d. Sustainability – of both expenditure and workload, where the aim is to reach a state of steady expenditure and workload, avoiding the build-up of a backlog of unavoidable, essential work by doing effective, targeted preventative maintenance.

The tool includes work identified from inspections, structural capacity assessments, “At-Risk” supports, sub-standard parapets, flood risk, scour risk, environment and local factors for all structure types. It does not yet include other risk programmes, such as hidden defects or safety-critical fixings.

The mainline of the A90 trunk road has been closed to facilitate road maintenance on 12 occasions over the following 5 full financial years:

2019-20 - 0

2020-21 - 2

2021-22 - 0

2022-23 - 5

2023-24 - 5

These closures took place overnight and averaged 13.5 hours per night in duration.

Additionally, there has been 53 slip road closures on the A90 trunk road over the same period. These overnight closures averaged 12.5 hours in duration. During these closures the mainline A90 remained open.

The A90 is a trunk road with considerable history having been periodically improved over the last 60 years to its current alignment and arrangement. The various improvements will have been designed in accordance with design standards that were in force at that time. As standards evolve they are not retrospectively applied to existing sections of road, unless changes or improvements at a given location are considered necessary.

This information is not held by the Scottish Government and responsibility for such rests with the British Transport Police and Police Scotland respectively.