Organisation: Transport for London
Date of Publication: May 2025
Uploaded to Knowledge Centre: 28 May 2025
This research shows that the number of people killed and seriously injured on borough roads in London reduced by 34% following the implementation of the 20mph speed limit between 1989 and 2013.
The report, the first of its scale in London, analyses more than 150 20mph schemes between 1989 and 2013, examining the three-year periods surrounding the implementation of each 20mph scheme.
TfL carried out the analysis to fully understand the impact of road safety measures across the city over a longer time span. The report shows that, with the exception of motorcycle fatalities, which did not change, 20mph schemes led to fewer fatalities and less severe injuries across every mode of travel.
The report shows that 20mph schemes significantly reduced the number of deaths and serious injury, including:
- A 40% reduction in the number of people killed (from 15 to 9), compared against the background trend of 7% fewer fatalities across borough roads
- A 34% reduction in the number of people killed or seriously injured (from 395 to 260), compared against the background trend of a 15% fall in people killed or seriously injured across borough roads
- A 75% reduction in the number of children killed (from 4 to 1), compared with no change across the control group. Additionally, a 50% reduction in children’s casualties (from 517 to 280), against the background trend within the control group of 20%.
- A 35% reduction in collisions and 36% reduction in casualties on borough roads, against a background trend of 12% fewer collisions and casualties across all borough roads
The report acknowledges other road safety improvement measures implemented between 1989-2013 and recognises that the implementation of 20mph schemes on borough roads is not the sole cause of improved road safety in this time.
For this reason, the report compares against the background trend seen across all borough roads in this period to provide ‘compelling evidence’ that 20mph schemes reduce the number of casualties regardless of all other road improvement.
TfL says the report demonstrates the positive impact of slower speeds on safety and supports the importance of similar measures in future plans to further improve safety in the capital.
Click the link below to access the full report:
https://tfl.gov.uk/corporate/safety-and-security/road-safety/safe-speeds