Maps Show the Impact of 20mph Speed Limit on Journey Times in Wales
An analysis of the first six months since the implementation of the 20mph speed limit in Wales has revealed that journey times have been affected. While journeys have become slower, there has been an improvement in journey time reliability, providing greater certainty on the duration of driving a specific route. Out of 60 points where data was examined, average journey times have increased in 55 cases. However, the majority of these increases have been less than 2 minutes, with over half of them being less than a minute.
Research indicates that vehicle speeds on main 20mph roads have decreased by an average of 4.3mph since the introduction of the speed limit on September 17, 2023. The purpose of the 20mph default speed limit was to reduce the likelihood and severity of road collisions, promote walking, cycling, and other forms of active transport, and contribute to overall mental and physical health benefits.
While it is too early to assess changes in casualty rates and CO2 emissions, the report highlights the need for three years of collision data post-implementation for meaningful comparisons. Public attitudes towards 20mph speed limits, including perceptions of traffic speeds, noise, and impacts on communities, will be evaluated through future research.
Data also shows a shift in the proportion of vehicles travelling at or below 24mph before and after the new law came into effect. Various monitoring sites across Wales recorded changes in vehicle speeds, with significant increases in compliance with the lower speed limit. Examples include Allt-yr-yn (Newport) where compliance rose from 43% to 68%, and Peniel, where it increased from 10% to 70%.
In conclusion, the data from the first six months of the 20mph speed limit in Wales indicates a mixed impact on journey times, vehicle speeds, and compliance. While journeys have become slower, there is increased reliability and adherence to the new speed restrictions. Further assessment over time will provide a more comprehensive understanding of the long-term effects of the speed limit on road safety and travel patterns in Wales.