Automobile injury trends in the contemporary fleet: Belted occupants in frontal collisions

Objective: As vehicle safety technologies and evaluation procedures advance, it is pertinent to periodically evaluate injury trends to identify continuing and emerging priorities for intervention. This study examined detailed injury distributions and injury risk trends in belted occupants in frontal automobile collisions (10 o’clock to 2 o’clock) using NASS-CDS (1998–2015). Methods: Injury distributions were examined by occupant age and vehicle model year (stratified at pre- and post-2009). Logistic regression models were developed to examine the effects of various factors on injury risk (by body region), controlling for delta-V, sex, age, height, body mass index (BMI), vehicle model year (again stratified at 2009). Results: Among other observations, these analyses indicate that newer model year vehicles (model year [MY] 2009 and later) carry less risk of Abbreviated Injury Scale (AIS) 2+ and AIS 3+ injury compared to older model year vehicles, with odds ratios of 0.69 (AIS 2+) and 0.45 (AIS 3+). The largest reductions in risk between newer model year vehicles and older model year vehicles occur in the lower extremities and in the risk of skull fracture. There is no statistically significant change in risk of AIS 3+ rib fracture or sternum injury between model year categories. Females are at greater risk of AIS 2+ and AIS 3+ injury compared to males, with increased risk across most injury types. Conclusions: For belted occupants in frontal collisions, substantial reductions in injury risk have been realized in many body regions in recent years. Risk reduction in the thorax has lagged other body regions, resulting in increasing prevalence among skeletal injuries in newer model year vehicles (especially in the elderly). Injuries also remain common in the arm and hand/wrist for all age ranges studied. These results provide insight into where advances in the field have made gains in occupant protection and what injury types remain to be addressed.研究目的：随着汽车安全技术与评价规程的迭代升级，定期评估损伤趋势以明确持续存在及新兴的安全干预重点颇具必要性。本研究依托美国国家汽车采样系统碰撞调查数据库（NASS-CDS，1998—2015年），针对10点至2点方位的正面汽车碰撞中使用安全带的乘员，详细分析其损伤分布与损伤风险变化趋势。 研究方法：本研究按乘员年龄与车辆生产年份（以2009年为界分为前后两组）对损伤分布开展分层分析；构建逻辑回归模型，以碰撞速度变化量（delta-V）、乘员性别、年龄、身高、身体质量指数（BMI）以及车辆生产年份（再次以2009年为界分层）作为控制变量，探究各因素对不同身体部位损伤风险的影响。 研究结果：本次分析的核心发现包括：与旧款车辆相比，2009年及之后生产的新款车辆（车型年[MY] 2009及以后）中乘员的简明损伤定级标准（AIS）2级及以上、AIS 3级及以上损伤风险更低，优势比分别为0.69（AIS 2+）与0.45（AIS 3+）。新款车辆与旧款车辆相比，下肢损伤风险与颅骨骨折风险的降幅最为显著。不同生产年份车辆的乘员发生AIS 3级肋骨骨折或胸骨损伤的风险无统计学显著性差异。女性乘员的AIS 2+及AIS 3+损伤风险均高于男性，且在多数损伤类型中风险均有所升高。 研究结论：对于正面碰撞中使用安全带的乘员而言，近年来多个身体部位的损伤风险已得到显著降低。但胸部损伤的风险改善进度落后于其他身体部位，导致新款车辆（尤其针对老年乘员）中骨骼损伤的占比有所上升。此外，所有受试年龄组的乘员仍普遍存在手臂、手部及腕部损伤。本研究结果可为汽车乘员安全领域的技术进步带来的防护增益提供科学参考，并明确了当前仍需解决的损伤类型。