This paper examines the relationship between enforcement activity, vehicle speeds and injury crashes in New Zealand. Enforcement activity taken into account includes speeding infringements (camera and non-camera), visible speed camera activity and the introduction of marked State Highway Patrol cars. Estimated reductions in open road mean speeds of 0.7 per cent and 0.8 per cent were found, associated with each increase of 10 000 speed camera infringements and 10 000 other speed infringements respectively. Higher reductions, of 1.1 per cent and 1.6 per cent, were found in the 85th percentile speeds. An estimated injury crash reduction of 12 per cent was found to be associated with a 1 kilometre per hour reduction in mean open road speed during low alcohol hours. The relationships between enforcement, speeds and crashes apply to the systems in place in New Zealand over the study period of 1996-2002 and should not be assumed to apply beyond the range of the enforcement practices studied. (Author/publisher) For the covering entry of this conference, please see ITRD abstract no. E213669.
Abstract