The interactive use of a vehicle-trailer handling model is presented. The model is a high resolution simulation of general vehicle (passenger cars to multitrailer) handling, braking, and vehicle-barrier interaction which is exercised interactively with a “human driver” over a realistic road (pavement, shoulder, median strip, etc.). At all times during the simulation, the operator can simulate the use of any normally available controls, i.e., steering, braking, throttle. The model has been developed and/or used over a number of years under various contracts with NHTSA, FHWA, DOD, and a number of industrial companies. Included in the paper are the results of a simulation run involving driver performance, vehicle parameters, and roadway conditions.