Lower extremity (LE) injuries sustained in side impact car crashes are debilitating due to the loss of weight bearing function and long rehabilitation times. In Australia such injuries rank third in terms of Harm after the head and thorax. Moreover, it is estimated around 20% of the total annual motor vehicle trauma treatment costs are devoted to rehabilitation of such injuries.

Regulatory design rules protecting the knee, lower leg and ankle/foot in side-impact crashes do not exist. However, in order to adopt sensible mitigation strategies and appropriate design rules, it is essential to identify and validate injury mechanisms.

While considerable work has been carried out identifying lower limb injuries occurring in frontal crashes, little work has been carried out regarding side-impacts. Three injury mechanisms, identified from a real-world side-impact case-study analysis carried out at Monash University were proposed at a Melbourne crashworthiness conference in 2002 [2]. MADYMO computer models simulating nearand far-side occupants in three typical crash scenarios were constructed. Occupant kinematics and force outputs from the models were compared with the injuries and hence the mechanisms identified in the study.

Results from the simulations were compared to published, known injury tolerances and are presented in this paper. Injury countermeasures for these three side-impact configurations are also discussed.