The first city in the UK to introduce 20mph limits on almost all residential streets has seen very encouraging results published in an interim report (Surveyor 1/10/09).
In March 2008, Portsmouth completed a nine-month programme to implement signed-only 20mph speed limits on 410 of its 438km road network.
A report commissioned by the DfT has revealed that on roads where the average speed before the scheme was above 24mph, a reduction of seven mph has been achieved. This change was described in the Atkins report as ‘statistically significant’.
The report also found collisions dropped by 13% and the number of casualties by 15%.
Duncan Price, branch head of road safety at the DfT, said there was ‘general support’ for a ‘substantial expansion of 20mph areas’.
Simon Moon, Portsmouth’s head of transport and street managements, said: “This interim report is limited in what it can say about the 20mph scheme – we’ll have to wait until it has been running for three years before we get the full picture.
“But there are some encouraging signs, especially on roads where speeds were significantly higher than 20mph when we imposed the new limit.”