Supplementing Future Occupant Safety Assessments with Severe Intersection Crashes Selected Using the SAFER Human Body Model

Five intersection crashes between two vehicles, one autonomous and one manually driven, were investigated to identify the most severe crash scenarios for occupants in autonomous vehicles. The SAFER human body model and models of a semi-rigid seat and a triple-pretensioned, load-limited belt system were used to calculate occupant kinematics and injury metrics for the five scenarios. Both driver and passenger positions and upright and reclined postures were investigated. The kinematics and injury metrics were compared to those of traditional full-frontal crashes at 40 km/h and 56 km/h, with the purpose of complementing current frontal safety assessments with additional scenarios for assessing automated vehicle safety. The intersection crash with a vehicle turning left across the path of a vehicle arriving from the opposite direction (“left turn across path opposite direction” with velocities of 19 km/h and 66 km/h, respectively) was found to be the most severe of the five in terms of loading on the head, neck, pelvis, and lumbar spine. In fact, in the upright posture the lumbar spine loading was equal to that in the full-frontal 56 km/h crash. A second intersection crash, with the vehicle struck perpendicularly by another vehicle (“straight crossing path” with velocities of 63 km/h and 58 km/h, respectively) was found to be the most severe in terms of loading on the chest and the risk of slipping out of the belt due to oblique, far-side occupant kinematics. Notably, the full-frontal 56 km/h crash did not reproduce this kinematics. In all other respects, all of the intersection crashes were less severe than the full-frontal 56 km/h crash. The “left turn across path opposite direction” and “straight crossing path” crashes were identified as low velocity crash scenarios to be considered in the development of countermeasures and in future legislation and rating programs together with more stringent requirements in injury assessments.