Performance Evaluation of Two Computational Approaches for Vehicle Collision Simulation

A vehicle collision can be divided in three distinct time phases, the pre-collision, the collision and the post-collision phase. Usually during a traffic accident reconstruction the collision and post-collision phases are investigated in order for the accident reconstructionist to draw conclusions concerning the causes and the events that lead to the vehicle collision. The investigation of both phases is usually a repetitive procedure which terminates when the investigation results match the physical evidence drawn from the accident scene. The objective of the analysis of the collision phase is the determination of the velocities of both vehicles prior and post collision. For the computational simulation of the collision phase two main approaches exist in the literature, the energy-based approach, developed by McHenry, and the momentum based one, developed by Brach, both in the late 1970s. The objective of the analysis of the post collision phase is the reconstruction of the trajectories of both vehicles from the point of collision to the point of rest. For the computational simulation of the vehicle trajectories different approaches exist, such as their approximation using geometric curves and the application of the equations of motion for each vehicle after collision. In the present paper two algorithms for vehicle collision reconstruction have been set up in Matlab. Each one utilizes a different approach for both the collision and the post collision phase. In more details the momentum-based approach has been coupled with geometric approximation of the trajectories while the energy-based approach has been coupled with the equations of motion for the post-collision phase. Both algorithms incorporate a suitable optimization method in order to provide optimized results in terms of collision geometry, collision physics and post-collisional trajectories of the vehicles. In order to evaluate the performance of both algorithms, the vehicle collisions described in details in the RICSAC database have been used. The results of each algorithm are compared with each other as well as with the measured quantities existing in RICSAC database.