Slower speeds, safer streets: 20mph schemes improve road safety

New research by Transport for London (TfL) has revealed that 20mph schemes have significantly reduced the number of people killed or seriously injured on London roads.

Aiming to assess the long-term impact of road safety measures, the research analysed over 150 20mph schemes introduced between 1989 and 2013, comparing data from the three years before and after implementation. And, with the exception of motorcyclists, the data reveals that there were fewer fatalities and injuries among all other road users.

According to the report, road fatalities fell by 7% across all London borough roads but dropped by a striking 40% on roads where the 20mph schemes were introduced. Similarly, collisions fell by 35% and casualties by 36%, compared to a just 12% reduction on other London borough roads.

The research recognises that other road safety measures implemented during this time are likely to have also contributed to the improvements.

Chief Safety Health and Environment officer at TfL, Lilli Matson, said: “It is brilliant to see the long-term analysis in this report. It contains hugely important findings which show the difference that 20mph speed limits have made to road safety in London, and we are able to fully understand the impact of road safety measures across the city over a longer time span. Lower speed limits save lives.”

In light of this research, it is expected that more boroughs will adopt similar measures to improve safety. Currently, twenty-one of the thirty-three boroughs in London have a default 20mph speed limit and there are plans to expand the scheme to more areas.

The Welsh government reduced the default speed limit in late 2023 and has revealed similar findings – recording a 28% drop in the number of people killed or seriously injured on 20mph and 30mph roads year-on-year.

Speaking on the research, Will Norman, walking and cycling commissioner, said: “This compelling new analysis shows clearly that lowering speeds is saving lives. Slower speeds not only protect the most vulnerable, they also help create safer, more welcoming streets, and are a vital part of building a safer London for everyone.”