Crashworthiness evaluation of an intercity coach against rollover accidents

Rollover accidents can result in serious consequences to vehicle occupants if necessary safety measures are not taken. Two significant measures that can be implemented to minimise occupant injury risk during vehicular rollover events are structural adequacy of the vehicle against crushing and occupant protection by using passive protective devices, such as safety belts and air bags. The aim of this study is to evaluate the structural resistance and passenger injury risks and compare the effectiveness of safety belt usage during a simulated rollover event. In this study, a 13 m long TEMSA bus was used as the vehicle. A total of eight occupants were placed in the critical places of the bus by considering the structurally weakest sections. Three different occupant protection cases were considered: (i) no safety belt; (ii) two-point safety belt and (iii) three-point safety belt. A standard rollover procedure was simulated using non-linear finite element code LS-DYNA. Head and neck injury criteria were used for all three cases to evaluate the effectiveness of seat belt usage on occupant protection. Simulation results clearly illustrated that if occupants had no seat belt protection they suffered serious risk of injuries. Moreover, two- and three-point safety belts provided somewhat similar protection levels for most of the occupants. On the basis of findings, use of two-point safety belts in all the seats of the TEMSA buses was recommended because of their ease of handling.