| Roadside safety appurtenances, including flexible longitudinal barriers, end terminals, and crash cushions, are designed to protect errant vehicles from roadside hazards. However, in order to design, test, and determine appropriate warrants, the real-world ran-off-road impact conditions must be identified. Most importantly, this includes the distribution of the angles and speeds at which vehicles exit the roadway. This requires the reconstruction of ran-off-road crashes.; However, reconstruction procedures for longitudinal barriers, crash cushions, and many other roadside hazards are not available in literature. This dissertation details the development of reconstruction procedures for ran-off-road crashes and illustrates its implementation through the development of procedures for flexible longitudinal barriers, end terminals, and crash cushions.; These procedures will be used in NCHRP Project 17–22, entitled “Identification of Vehicular Impact Conditions Associated with Serious Ran-Off-Road Crashes” in order to determine the angles and speeds during an off-road excursion. This information will then be used for refining the guidelines for roadside safety countermeasures and for calibrating roadside safety simulation models, as well as identifying the roadside features involved in the greatest number of serious crashes. This will help designers spend safety dollars on improvements that will have the greatest likelihood of reducing serious injuries and fatalities. |
