Queen's Policy Engagement

London is proposing 20mph speed limits – here’s the evidence on their effect on city life

Following the recent decision to lower speed limits in central London to 20mph, Dr Ruth Hunter looks at similar schemes across the UK to see what London can learn from other cities.

London is proposing 20mph speed limits – here’s the evidence on their effect on city life

A new speed limit of 20mph has been proposed for roads in central London. The plans, which would reduce the limit to 20mph within the Congestion Charging Zone, are part of the “Vision Zero” strategy, which aims to “eliminate deaths and serious injuries from London’s transport network by 2041”.

The main reason for reducing traffic speed is to lessen the likelihood of a collision – and to reduce the severity of road traffic casualties. Research indicates that if a pedestrian is struck by a vehicle at 24mph, they have a 10% risk of dying. This goes up to 25% at 32mph, and 50% at 41mph. A reduction in speed of as little as 1mph is associated with a reduction in casualties of up to 6%.

Yet plans for the 20mph limit in London have been controversial. Some question the impact it will have on increased traffic congestion and air pollution. Retailers are concerned it will discourage customers from visiting the city centre due to increased congestion. Others question the need for a 20mph limit in areas where congestion means it is rarely possible to go any faster than that. So what’s the evidence on 20mph limits so far?

To continue reading the article please click here. 


The featured image has been used courtesy of a Creative Commons license. 

Article first appeared in The Conversation.

Dr Ruth Hunter
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Dr Ruth Hunter is a lecturer and Research Fellow in the School of Medicine, Dentistry and Biomedical Sciences. Her research interests are in physical activity and public health, particularly regarding the development and evaluation of complex interventions for behaviour change at the individual, community and population level.

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