Beyond the generalization of the belt wearing, the improvement of the frontal impact protection is one of the most efficient action to reduce the number of the severe road victims. However, the attempt to evaluate the potential gains shows some important limitations to this efficiency and indicates the necessity of complementary actions. Among them:​

• the front-end of the trucks needs to be modified to avoid underide and too severe decelerations of car occupants,
• due to the interaction between the protection in frontal and in lateral impact, the gain in frontal could be lost by an increase of the aggressiveness of the impacting car in side collisions,
• in car-to-car head-0n collisions, the gain would be reduced by the increasing aggressiveness of the heavier car.

The author presents the quantification of the expected gains for the most prioritary countermeasures, discusses the major interactions between them, and tries to define the required conditions to optimize the whole safety system.