Question to the Department for Transport:

To ask the Secretary of State for Transport, whether it is his policy that speed restrictions on national roads can be introduced for reasons other than vehicle safety.

Traffic authorities, including National Highways for the strategic road network, set local speed limits in situations where local needs and conditions suggest a speed limit which is lower than the national speed limit. The Department issues guidance to English authorities on setting local limits.

Enforceable speed limits can be set for reasons other than road user safety: for example, variable mandatory speed limits can smooth traffic flow and reduce congestion. And where limits for air quality are in danger of being exceeded, compliance with those air quality limits could be an important factor in the choice of speed limit.

To achieve compliance with a new speed limit there should be no expectation on the police to provide additional enforcement beyond their routine activity, unless this has been explicitly agreed.