20mph zones effective in reducing road casualties

20mph zones are effective in reducing the number and severity of traffic collisions and casualties – according to a review involving researchers from the University of East Anglia.

The research, led by Queen’s University Belfast and published today, provides important evidence to support the implementation of 20mph speed zones across the UK and Europe.

Funded by the National Institute for Health Research (NIHR), the research is part of the largest and most comprehensive study to date into the effects of 20mph speed limits and speed zones to be undertaken in the UK.

Speed limits typically involve legislation and road signage whereas speed ‘zones’ also involve the use of physical traffic calming measures such as road narrowing and speed humps.

Road traffic injuries are a leading cause of preventable death globally. According to the WHO, the tenth leading cause of death worldwide is a result of road injury.

Dr Ruth Hunter, Reader from the Centre for Public Health at Queen’s University Belfast explains: “The primary reason for the introduction of interventions to reduce traffic speed is to lessen the likelihood of a collision occurring, and to reduce the severity of road traffic casualties.”

Dr Karen Milton, from UEA’s Norwich Medical School, said: “Our review looked at the effectiveness of 20mph speed interventions. We found that 20mph ‘zones’ which include physical traffic calming measures such as speed bumps and chicanes are associated with a reduction in the number and severity of collisions and casualties.

“There was insufficient evidence to draw conclusions on the effectiveness of 20mph ‘limits’ which include signs only and no physical infrastructure.

“Our ongoing research, which is evaluating 20mph speed limits in Edinburgh and Belfast, will help in understanding the effectiveness of signs only interventions.”

The research was led by Queen’s University Belfast and conducted in partnership with researchers from UEA, the University of Edinburgh, University of Cambridge, University of Exeter and NHS Health Scotland.

‘Effects of 20 mph interventions on a range of public health outcomes using the meta-narrative method’ is published in the Journal of Transport and Health on October 4, 2019.

Study Medicine at UEA

More world-leading research