The simulation model presented in this report is capable of analytically predicting the dynamic responses of the unibody passenger car during a rear-end barrier impact. A 5 degree-of-freedom system consisting of a rigid barrier mass, four vehicle masses, and seven nonlinear resistances represents the vehicle impacting the barrier, or vice versa. Five equations of motion are derived and ten initial conditions are specified for the model to define an initial-value problem. Due to the complexities of force-deformation characteristics of the resistances, the solution is derived by a numerical method. A computer program in PL/I for the IBM 360/65 is developed to perform the solution. Output data are available in both numeric and graphic forms. The simulation results are in good agreement with the results of the actual barrier test. Examples of application are given to demonstrate the usefulness of the simulation model in investigating various problems of practical interest.