Witnesses' estimates of the speeds of traffic accidents.

Using as data base the fatal pedestrian accidents occurring in London in 1970-71, the usefulness of police reports for estimating the speeds of road traffic accidents was investigated. Two approaches were used: correlating estimates by different witnesses of the speeds, and relating vehicle damage to estimated impact speed. The aim of this paper has been to show that police reports, when used with care, can provide an estimate of speed that is sufficiently accurate at least for comparative purposes within the sample of accidents studied.