Chester and Cheshire West (C&CW) has recently undertaken its first review of the 20 mph Speed Limit Programme.
A an overall reduction of 0.4mph in average speed across all schemes after year 1
A 65% reduction in road traffic collisions
A 40% reduction in Killed and Seriously Injured (KSI) road traffic collisions
A 69% reduction in Slight road traffic collisions
A total of 15% less vehicles travelling above 25 mph (based on traffic daily flow)
A total of 17% less vehicles travelling above 30 mph (based on traffic daily flow)
14 scheme areas where speed has increased on 20 mph roads
22 scheme areas where speed has decreased on 20 mph roads
A cost saving to the community in road traffic collisions of £2.6m (based the Department for Transport’s current average cost of a road traffic collision).
Very little complaints from local residents since the 20 mph speed limits were introduced. The few complaints that have been received were predominately why roads within the scheme areas were not included in the 20 mph programme
It should be stressed that data collected after 1 year is weak evidence on such schemes. After 3 years the evidence one way or another will be stronger.
An initial overview is that the picture is positive. The low decease in overall speed (0.4mph) in the Speed Limit zones is very typical. In some zones the reaction of drivers was very encouraging but in other areas it had a negative effect. Changing driver culture is very difficult and takes time.