Based on the one hand, on the examination of European statistics giving the distribution of hit areas for vehicles involved in frontal collisions, and, on the other hand, the analysis of two cases of accidents drawn from the Peugeot-Renault association's multidisciplinary survey, we are studying the behaviour of vehicles and occupants in asymmetrical frontal collisions, especially with a fixed, inclined barrier, using a theoretical approach with a mathematical model and a practical analysis.