Results of Selected Applications to Actual Highway Accidents of SMAC Reconstruction Program 741179

This paper reports the application of the Simulation Model of Automobile Collisions (SMAC) computer program to selected cases of actual highway accidents. Since SMAC was developed to allow accidents to be accurately reconstructed by operators without a detailed knowledge of engineering mechanics, recent developments have concentrated on providing a Start routine. This program automatically generates the inputs required for SMAC, including collision speed estimates, from a minimum amount of information available at the accident scene. A brief summary of how Start works is given, followed by a discussion of actual cases. The sensitivity of the final reconstruction to the various program inputs is discussed; this gives an indication of how the initial Start inputs may be adjusted to obtain a best fit with the minimum number of iterations of the program. Particular emphasis is given to those types of accident that are subject to large errors when reconstructed by the more standard analytical procedures; for example, intersection accidents and accidents involving large spinout trajectories.