Impact assessment
The option has been appraised in alignment with Scottish Transport Appraisal Guidance (STAG). This is the guidance used by the Scottish Government to assess transport interventions.
Proposed Change to National Speed Limits – All Users
Extensive research has been undertaken within the Milestone 3 Report to explore the impact of a reduction from 60 mph to 50 mph in the national speed limit on single carriageway roads in Scotland. Key findings from this are set out below.
Impact on Road Safety
In 2023, on Scottish single carriageway roads with a national speed limit there were 77 fatalities and 677 serious injuries. Preliminary data up to October 2024 indicates that road fatalities in Scotland are tracking 23% higher than 2023 levels.
An assessment of the road safety benefits of option 1 has been undertaken. This has identified that:
- After the first year of implementation there could be a reduction of at least 4 fatal, 14 serious and 6 slight injury collisions;
- over the 60-year assessment period there could be a reduction of at least 170 fatal, 720 serious and 378 slight injury collisions.
This outcome is supported by international research which shows that each 1 km/h reduction in traffic speed can lead to an 8% decrease in road fatalities and a 6% reduction in total casualties.
This strong correlation between lower speeds and reduced collision rates and severity indicates that the impact of this option is likely to lead to a safer driving environment.
Impact On Journey Times
Most journeys in Scotland cover a short distance and therefore the option under consideration is expected to have a minimal impact on typical travel times.
Industries that rely on time-sensitive transportation, such as those handling perishable goods including the fisheries industry, may experience slightly longer journeys. An example would be the journey from Scrabster to Gretna. Currently, for a goods vehicles over 7.5 tonnes this is a journey which would take approximately 6-7 hours. Under option 1, this would increase by approximately 4 minutes (less than 1% increase). However, as a result of narrowing speed limit differences and reducing driver frustration, option 1 is expected to enhance journey time reliability and reduce instances of disruptive road closures.
Impact on the Economy
As assessment was undertaken using the Transport Economic Efficiency (TEE) to assess the financial benefits and costs associated with option 1. This considered the economic value of people’s time, and the costs of running vehicles for various activities such as commuting and business logistics. This found a minor economic disbenefit arising from option 1.
Impact on the Environment
The environmental assessment considered impacts upon noise and vibration, local air quality and greenhouse gas emissions. While reduced speeds from Option 1 can lead to lower fuel consumption and emissions, contributing to improved air quality and reduced environmental impact it found that this would deliver minimum environmental impacts.
Proposed Changes to Speed Limits – Goods Vehicles over 7.5 tonne
Extensive research has been undertaken to understand the impacts of increasing goods vehicles over 7.5 tonnes speed limits from 40 mph to 50mph on single carriageway roads and from 50mph to 60mph on dual carriageways. Key findings from this are set out below.
Impact on road safety
In April 2015 in England the speed limits for goods vehicles (>7.5t) was increased from:
- 40mph to 50mph on single carriageways
- 50mph to 60mph on dual carriageways
An evaluation was undertaken which concludes that there has been no impact to safety as a result of the policy.
When goods vehicles over 7.5 tonnes travel significantly slower than other traffic, it can lead to frustration for other drivers, often resulting in unsafe manoeuvres. A higher speed limit of 50 mph on single carriageways for goods vehicles has been in place on parts of the A9 since 2014. Since this time there has been a reduction in collision trends often associated with driver frustration on that route, such as those involving overtaking manoeuvres. Therefore, increasing speed limits applying to goods vehicles (>7.5t) on single and dual carriageway roads may reduce instances of driver frustration and associated collision trends.
Impact On Journey Times
Experiences from other countries shows that raising the speed limit on single carriageways and dual carriageways for goods vehicles over 7.5 tonnes will likely lead to a small increase in actual speeds on these vehicle types.
Increasing the speed limits for goods vehicles over 7.5 tonnes will reduce the speed differential with other vehicles and could lead to improved journey time reliability for all road users.
Impact On The Economy
Increasing speed limits for goods vehicles over 7.5 tonnes can lead to reduced travel times, making the transport of goods more efficient. This can improve the logistics chain, allowing for more timely deliveries, especially important for perishable goods and time-sensitive shipments.
Impact On The Environment
Smoother traffic flow with fewer stops and starts, combined with reduced instances of harsh braking and acceleration, can lead to more fuel-efficient driving for goods vehicles over 7.5 tonnes (although it may lead to increased particulate matter in the air). This can reduce fuel consumption and associated emissions, albeit the impacts are expected to be minimum.
Impacts of Compliance with Speed Limits
The impacts described above would be dependent on the level of compliance with any change to speed limits.
Impact assessments
A pre-screening for the Strategic Environmental Assessment (SEA) has been undertaken with no responses received from statutory consultees and therefore has satisfied requirements. Following the consultation, an Equality Impact Assessment (EQIA), Childs Rights and Wellbeing Impact Assessment (CRWIA) and Business and Regulatory Impact Assessment (BRIA) will be undertaken.