Summary of impacts

This section provides a short summary of the key elements contained within this One Year After (1YA) Evaluation report of the M8 M73 M74 Motorway Improvements Project.

Project Description – What was the purpose of the project?

The project comprises the construction of three separately developed schemes:

the M8 Baillieston to Newhouse;
the M74 Junction 5, Raith; and
the M8, M73, M74 Network Improvements.

The three separate schemes were combined into a single contract for procurement purposes. The project was procured using a Design Build Finance Operate (DBFO) model and includes the delivery, management and maintenance of this section of the Central Scotland motorway and trunk road network until 2047. The specific improvements provided as part of the project were as follows:

a new motorway between Baillieston and Newhouse, completing the M8 between Glasgow and Edinburgh
improvements to Raith Junction on the M74, including an underpass for A725 traffic
a new, all-purpose A8 between Baillieston and Newhouse
upgrading the existing M8 between Easterhouse and Baillieston to incorporate an additional eastbound lane
upgrading the M73 between Baillieston and Maryville that links the M8 and M74, incorporating an additional lane on both northbound and southbound carriageways
upgrade of the M74 between Daldowie and Hamilton, incorporating an additional lane on both northbound and southbound carriageways between Daldowie and Raith Junction and an additional lane on the southbound carriageway between Raith Junction and Hamilton

The project was developed to complete the Central Scotland motorway network, to reduce delays and congestion prevalent at certain locations, such as at Raith Junction and to integrate the benefits realised from other recent motorway improvements, such as the M74 Completion and the M80 Stepps to Haggs project.

Operational Indicators – How is the project operating?

Based on the limited post-opening traffic flow information available at the time of the 1YA Evaluation, it is considered that traffic volumes across the upgraded road network have generally increased (in some locations significantly) following opening of the project. Post-opening annual average daily traffic (AADT) volumes within the M8 Corridor (between Baillieston and Newhouse) are up to around 27,000 vehicles per day (vpd) greater than pre-opening levels. Similar increases are observed on the M74 (post-opening volumes up to approximately 23,000 vpd greater than pre-opening levels) and on the M73 (post-opening volumes up to around 11,000 vpd greater than pre-opening levels). Significant increases have also been observed within the A725 Corridor, with an additional 13,700 vpd using the A725 to the south of Raith Junction.

While the available information suggests that traffic volumes have increased over the evaluation period, cognisance of the timescales for the comparison of pre and post-opening traffic volumes should be taken. This covers a period of five to seven years (between 2011 / 2013 and 2019) with an element of background traffic growth to be expected over this period. It is considered that the reductions observed in queuing and congestion and improvements in the reliability of journey times across the study area following opening of the project has played a part in increasing the volume of traffic using the road network, particularly in specific locations / on certain routes.

Through the mitigation of the most severe instances of the delays and congestion previously inherent on sections of the motorway network during peak periods, the project has resulted in significant reductions in journey times across the upgraded road network. Significant savings in journey time of up to 9 to 10 minutes within the M8 Corridor, up to 30 minutes within the A725 Corridor and up to 11 minutes within the M73 / M74 Corridor may have been realised following opening of the project. Journey times are now also more reliable compared to pre-opening conditions, with significant reductions in the variability of journey times observed within the M8 and A725 Corridors.

Initial indications suggest the project may have resulted in an overall improvement in road safety within its extents. The total number of personal injury accidents (PIAs) occurring on an annual basis has reduced (from seventy-seven to sixty-one) following project opening. Further investigation of the data, however, suggests that the number of fatal and serious PIAs may have increased following opening of the project (an increase from zero to two fatal and three to nine serious PIAs).

It is too early, at the 1YA Evaluation stage, to make any firm conclusions surrounding the impact of the project on road safety. The project’s impact on the number and severities of PIAs occurring within the vicinity of the upgraded sections of the motorway network will be confirmed as part of the project’s three year after (3YA) and / or five year after (5YA) Evaluation. At that point, longer term data will be available on which more robust comparisons of pre and post-opening data can be undertaken.

As a result of the new and improved pedestrian and cycle routes provided, it is judged that, based on the information available at the time of the 1YA Evaluation, the project is facilitating active travel within its vicinity. The measures provided link with existing walking and cycling routes and improve the connections between local communities, businesses and areas of employment. It can be concluded that the infrastructure provided is providing a means to access areas of employment within the wider study area for those without access to a car. However, no conclusions can be drawn about the journey purpose of observed trips in the absence of survey data. Also, no comparisons can be made with the pre-opening period as there is no data available on trip levels or whether any trips have been displaced from outside the study area. Furthermore, the project appears to be providing opportunities for active travel for leisure purposes, potentially providing additional benefits not measured as part of the project’s assessment, in terms of health and well-being.

Process Indicators – How well was the project implemented?

Process Indicators provide evaluation across the key elements of programme, project cost and process.

Construction commenced in February 2014 and the project was opened to traffic in phases – the upgraded Raith Junction, including the A725 underpass through the junction, opened to traffic on the 16^th February 2017. The westbound carriageway of the M8, between Baillieston and Newhouse, was opened to traffic on the 23^rd April 2017, with the eastbound carriageway opened to traffic a week later. The combined project, including the M8 / M73 M74 Associated Network Improvements element of the works, was opened to traffic on 1^st June 2017, with the overall project officially opened by The First Minister in August 2017.

Project final completion extended over a somewhat longer period than was predicted – extending into summer 2019. The project was, however, fully opened to traffic on 1st June 2017. Snagging and finishing works for the project were ongoing until 20th June 2019, which was dependent on a number of factors including weather, traffic management and minimising the impact on road users.

The project was taken forward under a DBFO contract – a full financial evaluation was undertaken by Transport Scotland prior to the award of the project’s DBFO contract. Details of project costs are, therefore, confidential and are not presented as part of the 1YA Evaluation. As such, a comparison of predicted and out-turn construction costs has not been undertaken a part of the 1YA Evaluation.

In terms of process, the mitigation which was included in the Environmental Statement (ES) has been implemented on site. Some aspects of the mitigation require attention or investigation, however, and further action may be required. Recommendations have been made in relation to certain areas of planting that may require re-planting or re-seedings, replanting of marginal vegetation at certain Sustainable Urban Drainage System (SUDS) locations to aid the ES commitments relating to wetland habitat extension. Responsibility for the removal of fly-tipped waste also needs to be established and a monitoring regime instituted to avoid further deposits of waste within the vicinity of the project.

The as-built drawings for the project were not available at the time of the site visits undertaken to inform the 1YA Evaluation. These were obtained following completion of the site visits. As a result, several ecological mitigation items were not inspected during the site visits, as these were not included in the ES mitigation drawings.

A Stage 4 Road Safety Audit (RSA) was not available at the time of the 1YA Evaluation.

A post-opening (Stage 3) Cycle Audit and an Accessibility Audit was not available at the time of the 1YA Evaluation.

Forecasting – How accurate were predictions?

The traffic volumes predicted by the traffic model, developed to support the project’s assessment, are broadly accurate, and well within the acceptable thresholds (+ / - 20%). Whilst there has been a slight overestimation of the volume of traffic using the M8 and A725 Corridors within the traffic model (up to 8% and 15% greater than actual traffic levels, respectively) and an underestimation of traffic using the M73 / M74 Corridor (between 7% and 17%) the magnitude of the variance is such that it is unlikely to have significantly impacted the project’s assessment.

The predicted average journey time savings, derived from the traffic models developed to support the project’s assessment, do not vary considerably from observed average journey time savings. It is worth noting, however, that actual average journey time savings tend to be greater when compared to predictions (most notably within the A725 Corridor).

Objectives – Is the project on track to meet its objectives?

The project’s objectives, in relation to its operation, focussed on reducing delays and improving travel time reliability within the M8 / A8 Corridor, at Raith Junction and within the M73 / M74 Corridor and on improving safety within the M8 / A8 Corridor.

The project has mitigated the most severe occurrences of congestion and delays occurring during peak periods over the extents of the upgraded road network. Significant savings in journey time of up to 9 to 10 minutes within the M8 Corridor, up to 30 minutes within the A725 Corridor and up to 11 minutes within the M73 / M74 Corridor may have been realised following opening of the project. While average journey time savings are of a lower magnitude, the available journey time data points to significant reductions in delays across the upgraded road network. Journey times are now more reliable compared to pre-opening conditions, with significant reductions in the variability of journey times observed within the M8 and A725 Corridors.

Initial indications, at the time of the 1YA Evaluation, suggest that the project may have resulted in an overall improvement in road safety within its extents, with the total number of PIAs occurring on an annual basis potentially having reduced (from seventy-seven to sixty-one) following project opening. Further investigation of the data, however, suggests that the number of fatal and serious PIAs may have increased following opening of the project (an increase from zero to two fatal and three to nine serious PIAs). It is too early, however, to make any firm conclusions surrounding the impact of the project on road safety, at the time of the 1YA Evaluation. Instead, the project’s impact on the number and severities of PIAs occurring within the vicinity of the upgraded sections of the motorway network will be confirmed as part of the project’s 3YA and / or 5YA Evaluation, at which point, longer term data will be available on which more robust comparisons of pre and post-opening data can be undertaken.

Costs to Government – Is the project delivering value for money?

The economic appraisal results for the project (as presented within the project’s Strategic Business Case (SBC)) predicted a Net Present Value (NPV) of £785.35m and Benefit to Cost Ratio (BCR) of 3.14.

Based on the comparisons of actual and predicted traffic volume and journey time savings, which suggest that the TEE benefits could be greater than expected (due to the project returning larger journey time benefits than predicted as part of the project’s assessment) the NPV and BCR of the project could, potentially, be greater than predicted.

Due to the nature of the project’s contract (as detailed in the Value for Money section) investment costs have not been reviewed as part of the 1YA Evaluation.

The likely benefits of the project extend beyond those quantified as part of the project’s assessment process. As such, it can be expected that the project is contributing towards the delivery of significant wider economic benefits at a regional and national economic level.

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