We attended the latest 20’s Plenty Conference in Edinburgh, focussing on the challenges and opportunities of appropriate roads in built-up areas having a speed limit of 20mph by 2025default 20mph speed limit across Scotland. In 2021, the Scottish Government and the Scottish Green Party published a policy programme with the commitment of a reduction in speed limits as part of the Bute House agreement. .
The strategy seeks to improve road safety and reduce casualties as well as encourage people to walk and cycle more. Implementing the reduction in the speed limit to 20mph in appropriate roads will be beneficial for both the community and the environment., However it will bring some key challenges for local authorities such as its significant impact on existing traffic elements.
The Conference – implementing a 20mph speed limit
The 20’s Plenty’s Edinburgh Conference was a great event for networking and best practice sharing. Our team themed their presentation around the practical issues that Scotland’s road authorities will need to address when implementing a potential change to a 20mph speed limit.
Reviewing speed limits
A misconception around the default 20mph limit is that the 30mph speed limits will no longer exist as the 20mph zones will take its place on all restricted roads. Not all roads with a 30mph limit are suitable to change to 20mph. Exceptions may need to be applied on these roads. This highlights the importance of clear communication, ensuring that drivers understand what limit applies.
This also includes reviewing all current Speed Limit Orders as well as the Highway Code, to appropriately reflect the road function and speed limit.
Application of the Safe System approach
Traffic speed management is a key element to improving road safety, which often results in a new set of expectations amongst residents. With lower speed limits, authorities must consider if communities will expect more enforcement, and if there are robust policies to support this.
Capturing this national strategy within a Safe System approach to road safety management is a key opportunity to reduce casualties. A Safe System approach recognises that human beings’ lives and health should never be compromised by their need to travel. The reduction of casualties is a shared responsibility for designers, contractors, network managers and users. All parts of the system must be strengthened so that the combination of measures introduce ‘layers’ to protect road users. Setting appropriate speed limits according to the features of the road helps to ensure that the body’s limit for physical trauma is not reached in the event of a crash.
Planning changes on roads
The National Strategy implementation will certainly mean a substantial change in existing speed limit signing regimes. Much of Scotland already has an advisory 20’s Plenty initiative in place, indicating which signing networks will need to be replaced, whilst adhering to streetscape principles. 
If roads were originally designed for 30mph or 40mph speed limits, these will carry specific geometry elements and visibility distances. When the lower speed limit is applied, if no changes are made to the road geometry, the risk is that people might feel safe to drive at higher speeds. And therefore be drawn to not adhering to the new speed limits.
At Project Centre, we have extensive experience in managing the re-design of roads for local authorities and private sector clients. Our consultants can assess what implications the change in speed limit would have on existing road features. Subsequently design the implementation of traffic calming measures, such as speed bumps, footways build outs, raised tables etc. Our engagement team is also experienced in gathering the thoughts and local knowledge of the public and stakeholders. This is paramount to understand specific challenges and design and build the right interventions at each location.
Increasing enforcement around 20mph zones
Wales became the first UK nation to decrease the default speed limit to 20mph in autumn 2023, followed by a three-month grace period. The Welsh Government established an approach towards enforcement that focused on education. Offending road users were given a choice between a fine and points, or roadside engagement during this period. Changing people’s hearts and minds is a key element to ensure long-term compliance. Enforcement will start from January 2024 following the end of the grace period.
As it stands, Police Scotland has no plans to alter their deployment model. Increased enforcement would require significant additional funding to promote the new default limit. 
Monitoring
The national strategy’s objectives suggest creating more pleasant streets and neighbourhoods. Monitoring those objectives will help us prioritise interventions.
The monitoring phase is paramount for the success of a scheme where a change to the speed limit is proposed. For example, if monitoring data showed speeding continuing on a specific location, authorities should implement additional measures.
The location of the speed cameras also plays a key role. These should be installed where collision risk is highest with the aim of improving road safety not catching people up.
The monitoring phase allows local authorities to better understand the actual impact of the 20mph strategy on local economies, as traders and service providers often perceive these schemes as a catalyst that could lead to a loss of business. 
How to ensure a smooth implementation of the 20mph speed limit
Local authorities must be very clear in their approach to the national 20mph strategy. Comprehensive and accessible engagement strategies can help authorities identify current challenges and ensuring the planning of targeted interventions that respond to the public’s needs.
Our team is expert in developing early engagement strategies to scope the public’s perception of their road environment. Our multi-disciplinary team collects the responses and develops 20mph zones designs that align to the community’s views. We also carry out the assessment of traffic elements that will be affected by the implementation of the new policy. These include, among others, the review and design of traffic signs, road markings, crossings and Traffic Regulations Orders.