Tests using dummies to simulate real world accidents are very important to study the mechanism of impacts, particularly pedestriancar accidents. Since only the dummy has been fitted with measuring devices like accelerometers, it is highly difficult to estimate the interaction between the dummy and the car to a fair degree of accuracy, using the measured acceleration-time histories. Therefore, it is necessary to measure the body forces in addition to the dummy accelerations in order to explain the impact mechanism more precisely. For this purpose, a body force measuring test vehicle has been developed at the Institute of Automotive Engineering, Berlin. A deformable unit which simulates the stiffness and geometrical measurements of a vehicle front is supported on load cells. This complete assembly is fixed on a very stiff chassis which allows to measure the magnitude and direction of forces during the impact.

To evaluate the results of the tests, certain criteria for estimating the severity of leg injuries were derived from the data of earlier investigations on cadavers. Both, the definition of a tolerance limit and a severity index, are given and their advantages and limits are discussed. Subsequently, the force measurements can be correlated to those of injury criteria in order to establish the validity of injury severity during the simulated accident.