Deaths among Drivers and Right-Front Passengers in Frontal Collisions: Redesigned Air Bags Relative to First-Generation Air Bags

摘要

Objective. After automakers were allowed the option of using sled tests for unbelted male dummies to certify the frontal crash performance of vehicles, most frontal air bags were depowered, starting in model year 1998, to reduce deaths and serious injuries arising from air bag deployments. Concern has been expressed that depowering air bags could compromise the protection of adult occupants. This study aimed to determine the effects of changes in air bag designs on risk of death among front-seat occupants. Methods. Deaths among drivers and right-front passengers per involvement in frontal police-reported crashes during calendar years 1998-2004 were compared among vehicles with sled-certified air bags (model years 1998-2004) and first-generation air bags (model years 1994-97). Frontal crash deaths were identified from the Fatality Analysis Reporting System. National estimates of police-reported crashes were derived from the National Automotive Sampling System/General Estimates System. Sled certification status for model years 1998-2004 was ascertained from published federal data and a survey of automobile manufacturers. Passenger cars, pickup trucks, sport utility vehicles, and minivans were studied. Stratified analyses were done to compute risk ratios (RR) and 95% confidence intervals (95% CI) for driver and right-front passenger deaths by air bag generation and crash, vehicle, and driver characteristics. Results. In frontal crashes, overall RRs were 0.89 for driver deaths (95% CI=0.74-1.08) and 0.89 for right-front passenger deaths (95% CI=0.74-1.07) in sled-certified vehicles compared with first-generation air bag-equipped vehicles. Child right-front passengers (ages 0-4, 5-9) in vehicles with sled-certified air bags had statistically significant reductions in risk of dying in frontal collisions, including a 65% reduced risk among ages 0-4 (RR=0.35; 95% CI=0.21-0.60). No differences in effects of sled-certified air bags were observed between drivers ages 15-59 and 60-74 in sled-certified vehicles, both of whom had RRs slightly below 0.90 (non-significant). Among occupants killed in sled-certified vehicles, police-reported belt use was somewhat higher than in first-generation vehicles. Conclusions. No differences in risk of frontal crash deaths were observed between adult occupants with sled-certified and first-generation air bags. Consistent with reports of decreases in air bag-related deaths, this study observed significant reductions in frontal deaths among child passengers seated in the right-front position in sled-certified vehicles. Higher restraint use rates among children in sled-certified vehicles and other vehicle design changes might have contributed partially to these reductions.