Vehicles in collision can be said to be incompatible if the deformation and structural characteristics mean the occupant loads are unequally distributed between the vehicles. Current crash testing does not consider vehicle safety in terms of the occupants of an opposing vehicle despite the obvious problems associated with incompatible vehicle sizes and structures. Real World accident data can be used to study the effects of vehicle structure on injury outcome in a number of impact types.

This study examines the structural features of car fronts and sides by reviewing real world accident cases Where both vehicles were available for examination. Cases are studied to see how the structures previously classified interact. The residual damage to each vehicle is assessed and the load transmission paths identified. Cases with low injury outcome can be compared to those with more severe injuries to see if the vehicle structure influences injury outcome.