In car-to-pedestrian collisions the lower limbs are usually struck first and the pedestrian’s head arcs downward to strike the bonnet (hood) surface. Approximately 60% of pedestrian head strikes to vehicle front structures are to the bonnet, often supported by underlying reinforcement and engine bay structures. Pedestrian-friendly engine bay packaging and bonnet design has the potential to reduce the severity of the resulting head injuries. In order to achieve this aim, the important criteria for good pedestrian protection must be identified by understanding the physics of the impact and through impact testing. Much can still be learned from the protection levels offered by current vehicles especially in the bonnet regions where low Head Injury Criteria (HIC) are recorded during a headform impact.

In this paper the results of 70 headform impacts to the bonnets of seven European vehicles are examined. The vehicles represent the current European population and the tests were part of a series commissioned by ACEA (European Automotive Manufacturers Association). The effect of reinforcement and hard contact are described and the general principles of good structural design are given.