A TfL Study Confirms that 20mph Speed Limit Saves Lives

A long-term study by TfL shows that the number of deaths and serious injuries on borough roads caused by accidents significantly dropped in areas with a 20mph speed limit. The study was conducted between 1989 and 2013 and analysed three-year periods surrounding the implementation of more than 150 20mph schemes.

This data will help TfL to work towards achieving the Mayor’s Vision Zero plan. The plan aims to completely eliminate deaths and serious injuries caused by road accidents in London by 2041 while encouraging walking, cycling, and the use of public transport to reduce reliance on private hire vehicles.

The report shows reduced fatalities and severe injuries across every mode of transportation, except motorcycles, which did not change. Here are some key stats:

• A 40% reduction in the number of deaths (from 15 to 9) caused by accidents compared to all borough roads, where the number of deaths only declined by 7% over the same period.
• A 34% decrease in the number of deaths or serious injuries (from 395 to 260) compared to only 15% fall across other borough roads.
• A 75% reduction in child deaths (from 4 to 1) compared to no change across the control group.
• A 50% reduction in children’s casualties compared to only a 20% drop in the control group.
• Overall, a 35% reduction in collisions and 36% reduction in casualties were observed in the areas with 20mph speed limit, compared to only 12% drop in collisions and casualties across all borough roads.

The research shows that road safety and slow speeds are directly linked with each other. As a result, the local authorities are planning to implement similar measures in future throughout the capital. In fact, 21 out of 33 boroughs already have a default 20mph speed limit. The rest is expected to follow suit soon.

Source:https://tfl.gov.uk/info-for/media/press-releases/2025/may/powerful-new-long-term-tfl-research-shows-20mph-speed-limits-save-lives-on-london-s-roads