Injury Patterns Among Belted Drivers Protected by Air Bags in 30 to 35 mph Crashes 1999-01-1062
The University of Miami's William Lehman Injury Research Center at the Jackson Memorial Medical Center conducts interdisciplinary investigations to study seriously injured restrained occupants in frontal automobile collisions. Engineering analysis of these crashes is conducted in conjunction with the National Crash Analysis Center at the George Washington University. The multi-disciplinary research team includes expertise in crash investigation, crash reconstruction, computer graphics, biomechanics of injuries, crash data analysis, emergency trauma care, and all of the medical specialties associated with the Ryder Trauma Center at Jackson Memorial Hospital. More than 300 injured occupants and their crashes have been studied in depth.
By careful study of injured crash victims, their vehicle and the crash scene, injury patterns emerge. These patterns form the basis for hypotheses which can be explored further by analysis of mass accident data, crash tests, and computer modeling. As a consequence, recommendations are provided for injury control measures.
One issue associated with second generation air bags is the concern that the performance in higher severity crashes may be reduced. The purpose of this study is to examine the kinds of injuries sustained by belted drivers in the higher severity crashes, based on cases from the Lehman Injury Research Center. The crash severity range examined is the upper limit anticipated by the tests required by the Federal standard for air bags, and for consumer information. These tests are at 30 and 35 mph, respectively.
Among the Lehman cases with the crash severity around 30 mph, impacts with narrow objects were over-represented. The common injury mode for the narrow object impact was liver laceration. These injuries were attributed to the safety belt rather than the air bag.
In the higher severity crashes, there were no head injuries. The chest injuries were the most life threatening. These injuries included rib fractures, and injuries to the liver, spleen, heart and lungs. Injuries to lower and upper limbs were also present in the higher severity crashes.
All cases had liver lacerations. Two different crash conditions may contribute to liver injury. They are: (1) a shoulder belt only, without the lap belt fastened and (2) a centerline crash with a narrow object at a crash speed around 30 mph. In the centerline pole crashes, the belt loading appears be the initial source of injuries to the liver.
The air bag and three point belt system appears to be providing high levels of protection to belted drivers in car-to-car crashes for the severity range of 30 to 35 mph. However, the combined belt and air bag loading may be excessive in some centerline crashes with narrow objects.