Organisation: Parliamentary Office of Science and Technology (POST)
Date of Publication: April 2025
Uploaded to Knowledge Centre: 20 May 2025
This report says there is strong evidence that 20 mph limits and zones are associated with reduced road casualties and fatalities. After Wales introduced a default national speed limit of 20 mph on restricted roads, casualties on 20 mph and 30 mph roads in Wales declined by 24% in April to June 2024 compared to the same period in 2023 (before the national default 20 mph speed limit was introduced).
The report goes on to say that Introducing 20 mph limits and zones may have wider benefits to physical and mental health, including encouraging active travel (such as walking and cycling), improving air quality and reducing noise pollution. However, very few evaluations measure health outcomes directly, which can make it difficult to attribute health benefits directly to the introduction of 20 mph interventions.
Access the report via the link below:
https://researchbriefings.files.parliament.uk/documents/POST-PB-0065/POST-PB-0065.pdf