Senior Impact Protection Systems

To assess elderly occupant protection in frontal as well as near-side impacts two restraint systems were designed to reduce loading of the chest and thereby reduce the risk of rib fractures which are common among the elderly population. The frontal protection system is called the split buckle (SB) system, and the side impact protection system is a pre-crash dual airbag (Pre-Crash SAB). The split buckle system comprised a separated diagonal and lap portion of the belt with the aim to add more load to the upper part of the body such as the clavicle and hence reduce the load on the lower part of the chest. The system was evaluated using a 50% THOR and PMHS tests in a generic sled test setup at 35 km/h. The side airbag system comprised a dual bag design mounted in the seat. One pre-crash airbag with 10l volume triggered at -25ms pre-crash and one standard side airbag with 22l volume triggered at +3ms. The dual bag system was evaluated in a Euro NCAP and a high speed IIHS side impact sled configuration (64km/h, IIHS+) with the 50%-ile WorldSID. For the split buckle system in frontal crash significant reductions in chest deflections was obtained compared to a state of the art belt system used in vehicles on the market today. Peak resultant chest deflection for the 50%-ile THOR dummy was reduced from 46mm to 32mm. Peak diagonal force with the reference belt was 4000N and for the SB system it was 5200N. For a 65 year old 46mm chest deflection corresponds to and injury risk of 77% and 32mm corresponds to 24% risk for an AIS3+ chest injury. For the pre-crash dual airbag system in the lateral crash configuration significant reductions in rib deflection was obtained. For the WorldSID 50%ile dummy the peak chest deflection was reduced from 34mm to 12mm in the Euro NCAP configuration. In the IIHS+ from 52mm to 29mm. For WorldSID 52mm chest deflection corresponds to 86% risk for an AIS 3+ chest injury for a 65-year-old occupant, while 29mm chest deflection corresponds to 7%. Using crash test dummies with a large measurement range, and assessing injury with age appropriate risk functions, show the need for improved restraint systems. The two systems evaluated in this study show good potential for addressing the issue with the fragility and frailty of the elderly population while maintaining good protection also for the younger population.