During recent years, the Highway Safety Research Institute (HSRI) has developed and validated two- and three-dimensional models describing the motions and forces acting upon an occupant during a collision. These inexpensive-to-operate models are performing with approximately 90% accuracy in parametric studies of classical crash configurations.In our own validation procedures, contacts with automobile development and design groups, and discussions with federal agencies, certain shortcomings of mathematical modeling procedures have been isolated. These include primarily the inability of the user to determine and input data to the computer programs and also to specify force, motion, velocity, and acceleration output data in a form applicable to the various vehicle design, human tolerance, and compliance tasks for which the models have been developed.As a part of the development of a new six-mass, three-dimensional crash victim simulator, a user-oriented interactive input/output language (OVERLORD) has been developed and is operational at HSRI. The objective of this tool is to make use of the HSRI and other similar models accessible to persons not highly trained in computer use. The program itself selects and positions the occupant in the vehicle and then automatically conducts the simulation. This is accomplished in a “conversation” between the user and the computer. The program asks the user certain basic questions such as: 1.What percentile occupant do you desire? 2.What is the impact velocity as well as type and direction of impact? 3.What standard vehicle geometry is desired-standard compact, subcompact? The new three-dimensional model and the OVERLORD program that prepares the input data, executes the computer run, and submits the output back to the user are described in detail in the paper. Comparisons between the predictions of the new model, predictions of the older HSRI three-dimensional crash victim simulator, and experimental data are included in the paper.