20 mph zone work
Study reveals enforcement is key to speed limits
An academic survey backs calls for law enforcement of 20 mph zones.
Researchers at Queen’s University Belfast (QUB) found that enforcement nearly halve the number of crashes. The report was initially published in 2019, and was often misquoted to show the failure of 20 mph zones. However, the report has resurfaced as the campaign for more 20 mph zones gains traction.
The report reveals that roads which enforce ‘speed zones’ – using humps and/or chicanes as well as 20mph signage – reduce collisions by 41%. Furthermore, serious and fatal injuries drop by up to 46%. However, studying the data from the Department of Transport has suggested that road signs alone are not proving a sufficient deterrent for speeders.
QUB reviewed DfT studies showing little evidence for the safety benefits of roads with 20mph signs only. The new findings from nine 20mph zones suggest signs alone are largely ignored by drivers. Speed ‘zones’, however, which feature physical traffic calming measures are showing some promising signs.
The DfT’s end of year report in 2018, however, found that 20mph zones in England failed to reduce air pollution or increase the uptake of walking or cycling over a four year- period. However, critics of the report cited the lack of enforcement including police forces unwilling and unable to enforce local schemes that lack legal force.
The Welsh government is looking to impose a blanket 20mph limit on all residential roads. However its consultation found less than 50% of respondents backed the plan. Despite this, the Welsh authority believes it improves safety and the environment and will push forward with plans.
The walking and cycling charity Sustrans welcomed the research.
20 mph zones work
Dr Ruth Hunter, of the Centre for Public Health at QUB, said:
“Our findings show a growing body of evidence to support the use of 20mph zones, showing them to be effective in reducing the number and severity of collisions and casualties. Our research also found an increase in participants walking and children cycling spontaneously in 20mph zones, indicating the potential indirect positive impact on physical activity.”
Director of insight Dr Andy Cope said:
“Lowering vehicle speed in residential areas to 20mph not only improves safety for our most vulnerable road users, but it can also help to reduce the dominance of vehicles making our streets and places more attractive to walk, cycle and enjoy.”