Influence of Complying with FMVSS 226 (Ejection Mitigation) on Side Airbag Occupant Out of Position Injury Assessment

The National Highway Traffic Safety Administration (NHTSA) has identified ejection mitigation as a top priority, issuing a final rule for FMVSS 226, Ejection Mitigation, in January of 2011 to set performance standards for a vehicle's ejection mitigation countermeasures to mitigate the risk of ejection through a vehicle's side window openings. The most likely countermeasures to be used for compliance with this standard are rollover activated curtain airbags that deploy from a vehicle's roof rail. However, this rule will most likely result in increases in the coverage area and inflator outputs of the curtain airbag; which may influence out-of-position occupant injury as measured in the test methods that have been outlined by the Side Airbag Out-of-Position Injury Technical Working Group (TWG). This paper presents a case study in which the out-of-position performance of a curtain airbag optimized for both ejection mitigation and side impact protection, as outlined per FMVSS 226 and FMVSS 214 respectively, is compared with that of one developed for side impact protection only for the same vehicle. Furthermore, the authors present a design concept that can be used to balance the requirements of FMVSS 226 with the injury risk from the deploying curtain airbag for out-of-position occupants.