Data from the National Crash Severity Study automated data file shows that the probability of fatality for victims of traffic accidents is strongly influenced by both the severity and the number of injuries received. This analysis classifies the occupants of towaway passenger cars into groups according to the severity level of the two most serious injuries, as defined by the Abbreviated Injury Scale. For each group, the fatality rate is computed as the proportion of each group which died within thirty days of the accident as a result of injuries received in the accident.

These fatality rates can be used to estimate the potential fatality reduction associated with a proposed regulation if appropriate assumptions of specific injury mitigation are made. This study gives an example of the process that uses this data to estimate the fatality reduction benefit of an hypothesized safety regulation.