This monograph examines the involvement of four wheel drive (4WD) vehicles in fatal crashes. It reports on the characteristics of fatal crashes involving 4WDs and compares them with the characteristics of crashes involving other passenger vehicles. The popularity of 4WDs has increased significantly over the last decade. In 1990 4WDs made up 12 per cent of all new car sales and by 1998 this had increased to 17 per cent. 4WDs are also starting to replace more traditional passenger cars on urban roads. This increase in popularity has given rise to an interest in the implications of 4WD safety in the road environment.