The objective of designing vehicle structure to minimize restrained occupant responses to multicar collisions requires a detailed study of all elements of the vehicle-occupant system. Two mathematical models, an 8 deg of freedom three-dimensional occupant and a 1500 deg of freedom vehicle structure, have been developed to allow such a detailed investigation. How these two models may be combined into a total system is described, along with initial validation efforts. The validations of the occupant model and the vehicle structure model will be supported by static load tests and two-car vehicle crash data for the particular case of side impact. Validation of the models merely establishes the feasibility of the approach, which is the principal conclusion to be derived from the analytical development to this point.