Analysis of Vehicle Kinematics, Injuries and Restraints in DRoTS Tests to Match Unconstrained Rollover Crashes

Multiple laboratory dynamic test methods have been developed to evaluate vehicle crashworthiness in rollover crashes. However, dynamic test methods remove some of the characteristics of actual crashes in order to control testing variables. These simplifications to the test make it difficult to compare laboratory tests to crashes. One dynamic method for evaluating vehicle rollover crashworthiness is the Dynamic Rollover Test System (DRoTS), which simulates translational motion with a moving road surface and constrains the vehicle roll axis to a fixed plane within the laboratory. In this study, five DRoTS vehicle tests were performed and compared to a pair of unconstrained steering-induced rollover tests. The kinematic state of the unconstrained vehicles at the initiation of vehicle-to-ground contact was determined using instrumentation and touchdown parameters were matched in the DRoTS tests. This study was performed to (1) evaluate the ability of the DRoTS to mimic the conditions of unconstrained rollover inside a laboratory, (2) demonstrate the repeatability of the DRoTS, and (3) to assess differences in ATD motion and related injury criteria for different vehicles with various combinations of safety features applied to different vehicles. All five DRoTS tests closely matched the first touchdown conditions of the unconstrained tests but the kinematics differed throughout the roof to ground contact. Some of these differences included vertical velocity and the magnitude of roll rate attained by the vehicles. In the three DRoTS tests that used driver and passenger ATDs, HIC and Nij values were found to be below IARV threshold values.