To improve occupant protection in side collisions, it is not sufficient to consider only lateral structures deformation characteristics. It is also necessary to modify frontal structures, which are generally designed for rigid barrier frontal impacts.In the following study, an analytical simulation model is used to optimize lateral as well as frontal deformation structures of passenger cars. The aim of the optimization is to minimize the risk of injuries of passenger car occupants, considering all relevant types of car-to-car and car-to-obstacle accidents.Structures built according to the analytical results are likely to show differences in their dynamic behavior compared with the calculated characteristics. As the analytical optimization yields optimum reduction of occupant loadings, differences of actual structures do not lead to optimally low loadings. Restrictions have to be considered as to what extent nonoptimal reductions in safety can be accepted.In full-scale tests and component tests, the performance of the structures has to be demonstrated.