Fatal side impact crash scenarios for rear seat and seat belt–restrained occupants from vulnerable populations

<b>Objective:</b> Previous studies have revealed vulnerability of school-age children and older adults in rear seats in motor vehicle crashes. Detailed information about crashes in which these fatalities occur could help improve vehicle and restraint design. <b>Methods:</b> Police accident reports were obtained for crashes from the Fatality Analysis Reporting System data set. Inclusion criteria were crashes in which there was at least one fatally injured restrained rear seat occupant between the ages of 6 and 12 or 55 and older in a passenger vehicle no older than 10 years at the time of the crash. Reports were reviewed for key crash data. Side impacts were selected for analysis. <b>Results:</b> Thirty-nine side impact crashes met the inclusion criteria, resulting in 46 fatalities of interest. Far-side or nondirect impact cases outnumbered near-side cases by 15–11 for juvenile occupants. Sixty-one percent of occupants were in vehicles with side airbags (SABs), all of which deployed for their position, although torso SABs were only present in 3 cases. Head injuries were present in all juvenile cases with injury data available and older occupants suffered equally from head and torso injuries. Impacts with pickup trucks and heavy trucks made up 31 and 22% of all cases, respectively. Three-quarters of cases were judged as survivable for the fatally injured occupant(s), and 5 of 7 cases deemed unsurvivable involved juvenile decedents. Further, of those deemed survivable, two-thirds had damage comparable in magnitude with the same vehicles in consumer information crash tests, evaluated by photo comparison. <b>Conclusions:</b> Older adults suffered thoracic injuries at a higher rate than older children—who suffered predominately head injuries—and most vehicles did not have torso SABs installed, which could have mitigated thoracic injuries. Side impacts in which younger occupants were killed were more severe than impacts that resulted in the death of an older occupant; however, vehicle damage and intrusion in many fatal impacts for both age cohorts appeared similar to that of consumer information testing. Large pickups and heavy vehicles were the striking vehicle in over half of all fatalities; vehicle designs and crash tests should continue to take this into consideration. This research highlights the need for continued work as the automotive safety community seeks to eliminate fatalities in motor vehicle crashes.

**研究目标**：既往研究表明，学龄儿童与老年人在机动车碰撞事故的后排座椅中易受伤害，伤亡风险较高。对这类致死碰撞事故的详细信息进行分析，可为车辆及乘员约束系统的设计优化提供科学依据。
**研究方法**：本研究从死亡分析报告系统（Fatality Analysis Reporting System）数据集获取了相关碰撞事故的警方事故报告。纳入标准为：事故中至少存在1名年龄介于6~12岁或55岁及以上的、已使用乘员约束装置的后排座椅乘员，且事故发生时搭载该乘员的乘用车车龄不超过10年。研究人员对报告中的关键碰撞数据进行审阅，并选取侧面碰撞事故开展针对性分析。
**研究结果**：共有39起符合纳入标准的侧面碰撞事故，涉及46名目标致死乘员。对于青少年乘员而言，远侧或非直接碰撞的案例数（15起）多于近侧碰撞案例（11起）。61%的乘员所在车辆配备了侧面安全气囊（side airbags, SABs），且所有适配位置的侧面安全气囊均正常触发，但仅3起案例配备了躯干侧面安全气囊。所有具备损伤数据的青少年乘员案例均存在头部损伤，而老年乘员则同时遭受头部与躯干损伤。碰撞对方为皮卡与重型货车的案例分别占总案例的31%与22%。经评估，四分之三的案例中致死乘员本可幸存；而7起被判定为无生还可能的案例中，有5起的死者为青少年。此外，在可幸存的案例中，经照片比对评估，三分之二案例的车辆损伤程度与消费者信息碰撞测试中同款车型的损伤程度相当。
**研究结论**：老年乘员的躯干损伤发生率高于年长儿童——年长儿童以头部损伤为主，且大多数车辆未配备躯干侧面安全气囊，此类气囊本可有效缓解躯干损伤。导致青少年乘员死亡的侧面碰撞事故严重程度高于导致老年乘员死亡的碰撞事故；但两类年龄组的致命碰撞事故中，多数车辆的损伤与侵入程度与消费者信息碰撞测试结果相近。超过半数的致死事故中，碰撞对方为大型皮卡与重型车辆，车辆设计与碰撞测试应持续考虑这一因素。本研究表明，在汽车安全领域致力于消除机动车碰撞致死事故的背景下，仍需开展进一步的相关研究，以推进相关安全优化工作。