The pedestrian protection given by a vehicle is assessed according to four independent impact test procedures, related to different body segments. Four impactors were developed specifically:​ leg, femur (or upper-leg), child head and adult head. These impactors, which are thrown against specific zones of the front face of the vehicle, allow the measurements of biomechanical criteria simulating the injury risk during the impact

Such test procedures are used by Euro NCAP and by the European regulation on pedestrian protection.

Concerning the upper-leg impactor, two biomechanical criteria are analysed:​ the sum of force and the three femur bending moments. A specific study has been carried out on the scatter of upper-leg tests by PSA Peugeot Citroën in cooperation with UTAC in order to assess the scatter of this set of biomechanical criteria in different laboratories.

In order to reduce the number of parameters of scatter and to isolate those linked to the upper-leg impactor, these tests have not been made on a full vehicle but on a simplified sub-system which permits to obtain biomechanical criteria very close to those obtained with a complete vehicle.

Tests conditions of the upper-leg impactor (weight and speed) vary in protocols (Euro NCAP as well as regulation) according to the vehicle style. About forty tests have been carried-out in each laboratory according to two different impact energies and with two different upper-leg impactors.

Results of those tests have enabled us to better understand and to quantify the scatter of the upperleg impactor and to improve the design of our vehicles for the pedestrian protection.