Motor vehicle crashes are a major cause of lower extremity trauma, especially leg/foot fractures. Leg/foot fractures occur frequently, are costly, and often result in lifetime impairments. Although current information on the biomechanics of these injuries is limited, it is known that they occur more often in frontal motor vehicle collisions, and that vehicular intrusions of the toe pan and instrument panel have been implicated as possible causes. Current motor vehicle safety standards are designed to protect vehicle occupants from serious injury in collisions with a change in velocity (▵V) of less than 30 mph. Preliminary evidence suggests that collisions resulting in these injuries may occur at delta V's well within the purview of current regulatory standards.This study was designed to develop a data collection instrument with which to capture detailed information on the crash reconstruction, biomechanics, engineering, and orthopaedic aspects of leg/foot fractures. Data are being collected on patients admitted to a Level 1 trauma center so that postulates can be developed regarding mechanisms of injury such as axial loading, translation, dorsiflexion, inversion, eversion, and bending. To be included in this study, the patient must have been a front seat occupant (restrained or unrestrained) of a late-model passenger vehicle or light truck/van involved in a collision, must not have been the victim of a rollover or ejection type crash, and must have sustained a lower extremity fracture distal to the femur.To date, data have been obtained for 42 trauma patients (22 men and 20 women). The mean Injury Severity Score for this group was 16, with an average of 2.2 lower extremity fractures distal to the femur per patient. The mean delta V was 28.4 mph (n = 39). Preliminary findings, including postulated patterns for mechanism of injury, are described.