Cutting speeds to 20mph ‘doesn’t stop car crashes’
CUTTING speed limits to 20mph in town and city centres barely reduces road deaths or crashes, says a study.
It found “little impact on long-term outcomes” after looking at before and after introduction on 76 roads in Belfast in 2016.
Comparisons with streets nearby and elsewhere in Northern Ireland that retained 30 or 40mph limits showed there were “no statistically significant differences”.
Tougher rules of the road led to quieter streets with fewer cars but did not actually cause drivers to slow down much.
Casualty rates fell by 16 per cent one year after the new limit and 22 per cent after three years, but these reductions were not considered “significant”.
Average traffic speed dropped by only 0.2mph after one year and by 0.8mph three years following rollout.
Weekly traffic volume fell by 57 vehicles one year and by 71 three years later, the said the report published in the Journal of Epidemiology and Community Health.
The biggest falls were in the morning rush hour when there were 166 fewer vehicles a week compared with similar streets where the 20mph speed had not been applied.
A significant decrease of 185 vehicles a week was also found when comparing all sites before, and three years after, rollout.
Study author Professor Ruth Hunter at Queen’s University Belfast said: “Future 20mph speed limit interventions should consider the fidelity [enforcement], context and scale of implementation.”
RAC road safety spokesman Simon Williams called the study “surprising”. He said: “It seems there is a serious problem with compliance.”
But he added: “Our research shows drivers are less likely to comply with a lower limit if they don’t believe it’s appropriate for the type of road.”