Intrusion and Lower Extremity Injury Risk In Offset Frontal Test Crashes

Lower extremity injuries resulting from motor vehicle crashes are both frequent and associated with considerable long-term impairment. Deformation of a vehicle's occupant compartment resulting in intrusion into the foot area is often cited as a source of many of these injuries. Similarly, collisions involving only a portion of a vehicle's front structure are typically said to produce greater intrusion than fully engaged crashes. The relationship between occupant compartment intrusion and the risk of lower extremity injuries was examined through a series of offset frontal crash tests of 1984-89 Oldsmobile Cieras. Results from both car-to-car and car-to-barrier test crashes with instrumented dummies confirm that there is a relationship between occupant compartment deformation and the loads acting on the lower extremities of vehicle occupants, even when crash severity has been controlled. Several of the measured relationships mimic biomechanical mechanisms that have been hypothesized to explain lower leg injury in real-world crashes. The results indicate that crash testing to assess the risk of lower leg injuries will need to focus on intrusion as well as injury measures from instrumented test dummies.