Organisation: Transport for Wales
Date of publication: February 2024
Uploaded to Knowledge Centre: 5 March 2024
This data covers peliminary weighted mean speed (mph) changes on main through roads following the national 20mph default speed limit on restricted roads.
Transport for Wales monitored millions of vehicle speeds in nine different communities across Wales before and after implementation.
Data gathered shows the average speeds on main roads dropped by an average of 4mph – from 28.9mph to 24.8mph. The report says this provides ‘clear evidence that speeds are moving in the right direction’.
These data are preliminary. Further post-implementation data will be collected during 2024, so post-implementation speeds presented here will be subject to change. For this reason, caution is recommended when interpreting. The data are representative of the areas monitored but may not be representative of all of Wales.
The data were collected on main through roads at 43 locations in nine settlements. All roads monitored had a 30mph speed limit before 17 September 2023 and a 20mph speed limit from 17 September 2023 onwards. All roads were largely free from physical restrictions that reduce traffic speeds at the time of monitoring.
Access the data via the Transport for Wales website:
https://tfw.wales/about-us/transparency/publications/default-20mph-speed-limit