Seat belts have been shown to provide excellent protection for occupants of modem passenger cars. Yet, seat belts have also been shown to cause some injuries, albeit generally less severe and not normally life threatening. Supplementary airbags in combination with seat belt webbing clamps are expected to reduce seat belt injuries by spreading the deceleration load on the torso and improving occupant kinematics during a crash. To date, however, there has been little scientific evidence in terms of field accident investigations to support this contention. The Monash University Accident Research Centre (Australia) has undertaken several case-control studies of crashed vehicles equipped with airbags. Vehicles have been inspected and occupants interviewed using the National Accident Sampling System (NASS) format. Data were available for 140 belted drivers involved in frontal crashes (delta Vs (velocity changes) between 21 and 60 km/h), including 71 airbag and 69 control cases. The results showed indications of overall benefits from the combination of airbags and webbing clamps, particularly in terms of a reduction in moderate and severe injuries and their associated costs. Indications of similar but smaller reductions were found when seat belt injuries only were considered. As expected, airbags reduced chest injuries across a range of severities. However, an increase in minor shoulder injuries was found among the airbag cases. This may result from changes to the occupant kinematics during a crash that stem from the combination of seat belt webbing clamps and supplementary airbags. (A)
Abstract