Fewer accidents and lower speeds in first year of 20mph limit

Published: Friday, February 15, 2019

The borough-wide 20mph speed limit on residential roads has led to a nine per cent reduction in accidents, figures suggest.

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Now, following the success of the scheme, councillors this week agreed to consider extending it to some main roads, subject to the support of local people.

The 20mph limit was introduced in June 2017 following public consultation that showed the majority of local residents were in favour.  Automatic traffic counters were installed at 88 sites which showed that traffic speeds in some roads went down by as much as six miles per hour.

An analysis of accident data showed that the total number of accidents on roads that had the lower speed limit fell from 195 in 2017 to 187. Accidents involving pedestrians, bikes and motorbikes fell by 19 per cent.

Accidents involving collisions between pedestrians and vehicles are three times less likely to be fatal if the speed of the impact is 20mph compared to 30mph. Studies have shown that at 30mph, 55 per cent of collisions result in pedestrian fatalities while at 20mph this figure drops dramatically to just 17 per cent.

Research carried out at Community Roadwatch events, at which police, the council and residents work together to use speedguns to check the speed of thousands of vehicles, found that more than 80 per cent of motorists are sticking to lower speed limits.

As well as being safer and encouraging other healthier modes of transport, slowing vehicle speeds reduces noise levels and helps improve air quality.

Since the 20mph limit was introduced on residential roads, there have been several requests made to the council to include main roads. At a meeting of the Strategic Planning and Transportation Overview and Scrutiny Committee on Tuesday, councillors agreed to consider introducing the limit to Northcote Road, Bolingbroke Grove, Bellevue Road, Putney High Street, Rectory Lane and Silverthorne Road if they meet certain criteria.

These criteria include whether traffic travels at an average of 24mph or more, if no additional traffic calming measures are required, if there is an additional benefit, such as improving safety on a busy shopping street, and if the proposal has local ward councillor and resident support. 

The council has also bought some speed indicator signs which it will deploy on roads where speeding is perceived to be a problem to remind drivers of the 20mph limit. It will continue to work closely with the police on the Community Roadwatch programme and further measures, such as more enforcement and speed awareness courses, are also being explored.

The council’s transport spokesman Cllr Jonathan Cook said: “It’s good news that the rollout of 20mph speed limits have helped reduce accidents. I’m especially pleased that accidents involving bikes and pedestrians have fallen so much, because one of the aims of the scheme was to make more active forms of travel safer so that local people are more likely to use them.

“We will continue to work with the local community and the police to keep an eye on traffic speeds and will consider extending the scheme to other roads that could benefit.”

Read the report

Read more about the 20mph speed limit in Wandsworth