Real-Life Fatal Outcome in Car-to-Car Near-Side Impacts-Implications for Improved Protection Considering Age and Crash Severity

摘要

Objective: Recent studies have shown that current side airbags, protecting head and chest, are saving lives in near-side impacts (Kahane 2007; McCartt and Kyrychenko 2007). The aim of this study was to analyze NASS/CDS real-life data on fatal trauma in near-side car-to-car crashes, stratified by age into non-senior and senior occupants. Furthermore, a hypothetical model explaining side airbag effectiveness as a function of lateral delta-v was presented. The model together with the field data was then used to demonstrate further enhancement of side airbag restraint performance. Method: Weighted NASS/CDS data from 1994 to 2006 for front seat occupants in near-side car-to-car impacts was used to calculate the exposure, incidence, and risk of fatal trauma with respect to lateral delta-v. The dataset was also divided into non-senior (10-59 years) and senior (age ≥ 60 years) occupants. The hypothetical model was created to adjust the NASS/CDS data to represent a car fleet fully equipped with current side airbag protection. The model was then used to evaluate the increase in effectiveness of improved side airbag protection achieved by increasing the lateral delta-v in the range where the airbag have most mitigating effect, increasing the airbag protection level within the delta-v range currently tested, and a combination of the two approaches. Results: From the NASS/CDS data, the median delta-v for fatal injury was 37 km/h for the total sample. When stratified with respect to age, the median delta-v for fatal injury was 41 km/h for non-seniors and 28 km/h for senior occupants. The exposures for both age groups were similar. However, the fatal incidence showed a difference in delta-v range between non-senior and senior occupants. Applying the airbag model increased the median delta-v to 40 km/h for the total sample and 47 and 30 km/h for non-seniors and seniors, respectively. Conclusions: Current side airbag systems offer very good protection for non-senior occupants up to delta-v 40 km/h. Though still high, the protection for senior occupants is lower. To enhance side airbag protection, the side airbag performance should be maximized where the fatal incidence is high. Therefore, to further reduce non-senior fatalities, the test speed should be increased. To further reduce senior fatalities, the protection level within severities currently tested should be increased. A combination of the two approaches would result in about a 40 percent increase of the side airbag effectiveness.