Newly published data has shown that the introduction of the 20mph (30km/h) speed limit across the London Borough of Richmond has improved road safety. This has wider implications for other countries also, showing that lower speed limits can save lives, while making little difference to journey times for drivers.
The borough’s 20mph (30km/h) speed limit was implemented in March 2020 and covers 97% of the borough’s roads. Taking speed recordings at 152 locations over a one-week period in May 2024, the researchers found that the measures introduced have produced a noticeable drop in overall traffic speeds, with average speeds on all the borough’s roads reducing by 2.6mph (4.2km/h). The story on Richmond's roads recording the highest speeds, saw average speeds reduce by an even greater margin of 4.4mph (7km/h).
Our data shows that significant speed reductions were achieved without causing delays for drivers. Research showed that journey times remain largely unchanged. For example, driving along Kew Road in 2023 took only 14 seconds longer than it did in 2019.
Councillor Alexander Ehmann, Lead Member for Transport and Air Quality said: "We are thrilled with the positive impact the 20mph limit has had on our communities. This latest data shows that our residents are at a lower risk of being involved in a collision than when our roads had 30mph limits. There was some considerable opposition to the change at the time of implementation, but these results more than justify the leadership this Council took on the issue."
Since the introduction, the average number of collisions per year has gone down from 338 before the 20mph limit was introduced to 301. At the same time, the number of pedestrian incidents has decreased, with the number recorded, falling by 24% making the borough’s streets safer for active travellers.
