The statistical study performed aims at quantifying the risks induced by varying levels of aggressiveness between cars involved in collisions with one another.

This aspect of motoring safety is often neglected. Monitoring or comparative evaluations of the protection provided always focus exclusively on interior protection for the model in question and neglect the level of risk imposed on the opposing vehicle.

The data are taken from the computer file of the French National Police. The data processed covers 45,678 drivers (including 8377 fatalities and severe injuries), all restrained occupants aged 65 years or less involved in collisions between accurately identified car models.

The examination covers head-on collisions, frontal impacts, side collisions and the sample as a whole.

The results verify the predominant influence of the aggressiveness of mass on the risks of severe injuries, although it is not always possible to evaluate the role played by associated parameters such as aggressiveness due to architecture or stiffness.

The severe injury rates (((Fatalities + severe injuries) x 100)/total occupants involved) for drivers do not vary in collisions between vehicles of identical mass class.

Finally, the study shows that certain car models reputed safe for the interior protection of their occupants prove on the other hand more dangerous for the occupants of the opposing cars. As a consequence it seems necessary that future ratings of real-world car safety take into account exterior risks observed for the opposing motorists for the model in question.