Safety Performance of Rear Seat Occupant Restraint Systems

Research was undertaken to determine the effectiveness of rear-seat outboard occupant restraint systems in passenger cars, focusing on the overall efficacy of two-point rear-seat occupant restraint systems and comparing the relative performance of two-and three-point rear-seat occupant restraint systems. While a significant body of literature exists comparing the safety performance of various types of front-seat occupant restraint systems, very little comprehensive accident data analysis (i.e., using large volumes of data) has been conducted to date comparing the safety performance of rear-seat occupant restraint systems.

For the study, the motor vehicle accident databases from five states were examined to determine the reduction in rear-seat occupant injuries associated with two-point and three-point rear-seat occupant restraint systems. Confounding factors such as accident type and rear-seat occupant age were examined to identify differences between front-seat and rear-seat environments. The National Accident Sampling System (NASS) was also examined, to determine the injury distribution of occupants and belted occupants in front and rear seats. Two independent analysis approaches were used to assess the overall safety performance of rear-seat occupant restraint systems. Neither approach showed a measurable difference between the safety performance of two-point and three-point rear-seat occupant restraint systems.