Comparison of Severity Affecting Factors between Young and Older Drivers Involved in Single Vehicle Crashes

Single vehicle crashes contribute to a significant amount of fatalities in the United States. At the same time, fatality crash involvement rates of young and older drivers are well above the average and both groups are identified as critical groups when it comes to highway safety. Therefore, the study described in this paper developed separate models to predict crash severity of single vehicle crashes by young and older drivers. By using the models, factors affecting towards increased crash severity were identified for each group and comparisons were made. Almost all the common identified factors influenced both driver groups in the same manner except in the case of alcohol and drug usage, which indicated an interesting finding in the case of crash severity of older drivers. Speeding and non-usage of a restraint device were the two most important factors affecting towards increased crash severity for both driver groups at all severity levels. Additionally, ejection and existence of curve/grade were determinants of higher young driver crash severity at all levels. For older drivers, having a frontal impact point was a severity determinant at all levels. County of residence and weather condition were not effective in making any changes with respect to crash severity at any level, while some other factors had a minimal affect. Findings of this study are beneficial in investigating the potential ways of reducing crash severity, which could also be influential in reducing the occurrence of crashes as well.