Impacts of bumpers on the legs of pedestrians are analysed by simulating accidents using comprehensively instrumented adult and child dummies with free-standing ability. The friction force between the feet and ground is found to be a significant factor in the kinematics of the pedestrian and his interaction with the bumper, vehicle and ground. The effects of bumper height, lead and deflection characteristics are evaluated experimentally in conjunction with a mathematical model of leg impact. Bumper impacts are not considered in isolation; results indicate that bumper positional requirements for reduced leg injury would be 12-14 in height and 5 in lead, but vehicle front end height is a more important factor in determining critical impacts of other body areas with the vehicle and ground. An energy absorbing bumper system with the facility to lift the leg on impact presents further possibilities of reducing loads on the leg.