The objective of this analysis is to evaluate the effectiveness of restraints in preventing injury-producing contacts of specific body regions, such as the head or chest, with specific interior components. In order to make comparisons by restraint use, an injury rate is calculated as the number of injury-producing contacts per hundred involved occupants. Data, including the Occupant Injury Classification (OIC), are from the 1988-92 National Accident Sampling System (NASS) Crashworthiness Data System (CDS). The analysis presented is limited to passenger vehicle drivers in towaway, frontal impacts.
Injury-producing contact rates are compared for four restraint configurations: unrestrained, three-point belted, driver airbag alone, and driver airbag plus three-point belt. For each restraint configuration, contact rates are compared by three categories of injury severity, AIS 1, AIS 2, and AIS 3-6, body region injured, and contact area producing the injury. The three-point belt provides substantial reductions in driver injury rates for head/face and torso contacts with the glazing, pillar/rails, and steering assembly. The addition of the driver airbag to the three-point belt appears to offer further reductions in these injury rates. The driver airbag alone did not show similar reductions, although sample size was very limited. Also, the injury rate for airbag contacts is more than three times the rate for belt contacts. The effects of occupant age, gender, and stature are identified as areas for further study.