The University of Virginia is investigating the biomechanical response and injury tolerance of the lower extremities in a vehicle crash environment. Studies of accident databases have shown that the widespread use of seat belts and airbags has increased the relative importance of debilitating lower limb injuries significantly. This paper discusses the methods used to address this problem, which include accident investigation, computer simulation, and laboratory testing. A representative accident case has been selected for simulation with the ATB occupant simulator. The results indicate that a strong correlation may exist between foot position on the brake pedal and the load transmitted to the heel of the braking foot. The results are less conclusive with regard to the effects of moderate amounts of intrusion (less than 20 cm). These simulations have set the stage for upcoming laboratory work involving an impact sled fitted with a special buck which provides toe pan intrusion, as well as a compound pendulum which will be used to perform highly controlled, component tests of lower limbs. The laboratory tests will make extensive use of the new Hybrid III Advanced Lower Limb.