Reducing the speed limit to 20 mph in urban areas

Traffic accident casualties fall with lower speed limits

The evidence of increased pedestrian safety at 20 mph is strong. The chance of a pedestrian being seriously injured orkilled if struck by a car is 45% if the car is travelling at 30 mph but only 5% at 20 mph.6 Government research showed that 20 mph zones reduced the incidence of traffic accidents by 60% and cutchild pedestrian and child cyclist accidents by 67%, while overall vehicle speeds fell by an average 9.3 mph (14.9 kph).7 There was no evidence that accidents increased on surroundingroads. Research by local councils produces similar results. For example, Havant Borough Council has imposed a 20 mph limit on 20 miles of road and has seen traffic accident casualties drop by a significant 40%.8

There are signs too that a policy of reduced urban speed limits would be acceptable to the public. Among viewers of a Carlton Television programme who responded to a survey, over 80% favoured a 20 mph limit on all residential roads in London.8 In continental Europe the public response has been largely positive. Graz, in Austria, adopted a 30 kph (18 mph) limit through most of the city, cutting serious casualties by over a quarter and dramatically reducing noise and air pollution. Fewer than 5 people out of 10 supported the initiative when it was first introduced, but 8 out of 10 support it now.8

The Association of British Drivers has, however, warned about the dangers of allowing local authorities to set their own 20 mph limits. The association thinks that decisions about where to implement slower speed limits will be made on a political basis, resulting in inappropriate limits on some roads. Inappropriate limits, it argues, will mean that drivers will be more distracted as they focus their attention on the speedometer and not the road ahead.9 It has called for limits to be “reasonable, consistent and above all, based on sound,established road safety principles.”9

Certainly there is a danger in focusing solely on lower speed limits as a means of reducing accidents. Other factors that contribute to road related deaths and injuries include alcohol, tiredness, and poor driving skills. Traffic calming measures and education to improve driver behaviour5 are also an essentialparts of road safety. Education should focus not only on drivers but also on parents and children.

Courts are too lenient

Moreover, imposing lower speed limits in isolation will have only limited impact. The fact that 70% of all drivers currently exceed the 30 mph limit reflects the relatively lenient attitude of the courts towards driving offences.4 Proper enforcement is as important as setting the limits in the first place. Nevertheless, if local authorities use lower speed limits sensibly, as part of an overall strategy, then the 20 mph speed limit offers a new opportunity for tackling the problem of child deaths and injuries on the road.