Question to the Department for Transport:

To ask the Secretary of State for Transport, what recent assessment his Department has made of the effect on the number of accidents of road speed limits in built up areas.

Authorities have been introducing more 20 mph limit and zone schemes across the country, including some which cover very large areas (such as Portsmouth). As the number of zones increase we would expect the number of accidents on 20 mph-limited roads to increase, simply as a consequence of the zones becoming more prevalent. This is not an indication that the 20 mph-limited roads are becoming more dangerous, but rather a reallocation of accidents from 30 mph-limited roads to 20 mph-limited roads. Atkins, and AECOM and Professor Mike Maher from UCL, have been commissioned to carry out research into the effectiveness of 20mph limits. The study will cover many aspects including effects on speed, collisions, casualties and modal shift. The research will also consider best practice, road users’ perceptions and effects on the quality of the environment.

The attached tables show the reported accidents by speed limit, road class and severity in GB for 2010 to 2013.