Abstract
In analyzing road accidents, it is important to estimate vehicle behavior based on the final position of the vehicle, damage profiles, tire scuffs, and so on. Consequently, the Collision Analysis and Reconstruction System (CARS) has been developed to improve the reliability of automobile collision analysis.
CARS can reconstruct the pre-impact, impact and post-impact phases of automobile collision and output vehicle accelerations, deformations, trajectories, tire yaw-marks and so on. In the CARS PC program two different impact models, an impulse-momentum impact model and a mass-spring impact model, are used in addition to Sakai's tire model and a tire yaw-mark model. The impulse-momentum impact model is based on the law of conservation of momentum and introduces a normal restitution coefficient and a tangential restitution coefficient at the impact center. The mass-spring impact model uses vehicle deformation characteristics. CARS users can select one of the two impact models according to the input data available and to the output data needed. For example, the impulse-momentum impact model mdy be used when vehicle deformation characteristics are not available.
Thi$,paper outlines the theory and output functions of the CARS PC program and demonstrates its applications to accident analysis.