This study deals particularly with off-road accidents; defined as accidents in which a vehicle is damaged and occupants may be injured after the vehicle leaves the road. These include most single vehicle accidents, those involving fixed object located off the road, and those in which vehicles overturn after leaving the road. A mathematical model is used to establish the frequency and severity of off-road accidents on rural roads in michigan, usa, using accident data from the files of the michigan department of state highways. The model ignores alignment and assumes that the effect of traffic volume on accidents is proportional to the average daily traffic. In this study the effect of adt was found to decrease with increasing volume. It was also shown that a curved alignment has a large effect on the rate and severity of off-road accidents.
Abstract