Biomechanical Assessment of a Rear-Seat Inflatable Seatbelt in Frontal Impacts

The biomechanical performance of a rear-seat inflatable seatbelt system was evaluated and compared with a 3-point seatbelt system which has a long history of good real-world performance. Frontal impact sled tests were conducted with Hybrid III anthropomorphic test devices (ATDs) and with post mortem human subjects (PMHS) using both restraint systems and a generic rear-seat configuration. Test results demonstrated: (a) reduction in forward head excursion with the inflatable seatbelt system when compared to that of a 3-point seatbelt; (b) a reduction in ATD and PMHS peak chest deflections and the number of PMHS rib fractures with the inflatable seatbelt system; and (c) a reduction in PMHS cervical-spine injuries due to the interaction of the chin with the inflated shoulder belt. These results suggest that an inflatable seatbelt system can offer additional benefits to some occupants in the rear seats. Future research should assess the field effectiveness, customer comfort and acceptance, and change in the belt usage rate with the inflatable seatbelt system.