To ask the Secretary of State for Transport, what assessment he has made of the effect of local authorities enforcing 20mph zones in built-up areas on the level of pedestrians involved in traffic accidents.

The Department has not carried out a study on the effect of speed enforcement in 20mph zones (which have traffic calming measures such as chicanes and speed humps) or on 20mph limits (which have signs only).

DfT guidance recommends that successful 20 mph zones and 20 mph speed limits are mutually reinforcing, i.e. the existing conditions of the road together with measures such as traffic calming or signing, publicity and information as part of the scheme, lead to a mean traffic speed compliant with the speed limit. Within this approach, to achieve compliance there should be no expectation on the police to provide additional enforcement beyond their routine activity, unless this has been explicitly agreed with the local traffic authority.