The aim of the research reported is to provide an understanding of the causes of urban road accidents. The work comprises 'in-depth' studies of the contributory factors in road accidents with emphasis on the role of the human factor. It is hoped that by determining the causes of accidents perhaps appropriate policies can be introduced for accident prevention and also for informing those at risk about accident prevention measures. A total of 1000 accidents was examined which had occurred in an area of Leeds, outside the central business district on roads with a speed limit of 40 mph or less. The study consisted of: collecting accident information; interviewing participants; visiting sites; assessing contributory factors; analysing information; and, interpreting results for policy implications. It is concluded that the study has provided new insights into accident causation and the database produced is likely to be a useful source for further research into factors affecting accidents.