Twenty's not plenty as effectiveness of 20mph speed limit without humps brought into question

Drivers ignoring 20mph speed limit where no physical infrastructure is present

With cities around the UK having their speed limits reduced to 20mph on the grounds of safety, a review involving researchers from the University of East Anglia (UEA) has revealed that 20mph zones are effective in reducing the number and severity of traffic collisions and casualties. 

The research, which was led by Queen’s University Belfast and published on 4 October, provided evidence to support the implementation of 20mph speed zones across the UK and Europe. 

The review was funded by the National Institute for Health Research (NIHR) and 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. According to the report, road traffic injuries are a leading cause of preventable death globally. However, the research showed that drivers are ignoring 20mph speed limits where there is no physical supplement to the signage. 20mph zones which are supported by physical infrastructure such as speed humps or chicanes have reduced accidents by around 46%. Dr Ruth Hunter, Reader from the Centre for Public Health at Queen’s University Belfast explained: “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.” Image Sources: Pixabay