The aim of this study is to identify how vehicle safety during side impacts may be enhanced by changes to the structures of bullet vehicles. Side impact tests being conducted around the world are focusing on the improvement of self-protection performance of target vehicles, based on existing vehicle fleets. However, the protection of occupants in the target vehicle is influenced both by the characteristics of the target vehicle and the characteristics of the bullet vehicle. Since test procedures for frontal impact compatibility are currently being planned, those that encourage homogeneity and good structural interaction among vehicles may also be beneficial for side impacts. Thus, it is necessary to investigate the design factors of the bullet vehicle in terms of side impact compatibility.

First, a study using FE simulation was carried out to develop an understanding of the major influencing factors relating to side impact compatibility. From this understanding, concept ideas for enhancing vehicle side impact compatibility were proposed. Second, FE simulation of a Full Width Deformable Barrier test was conducted with unmodified and modified vehicles to check that the test and assessment technique could correctly distinguish the improved performance of the modified vehicle. Finally, vehicle-to-vehicle tests using modified bullet vehicles were performed to demonstrate the principles identified in the FE simulation.

The results showed that the matching of geometry and stiffness in vehicle front-end structure contributes significantly to vehicle safety during side and frontal impacts.