Pre- and postimpact phase modelling of vehicular collisions

Mathematical models are developed and evaluated in this work for reconstruction of pre- and post-impact trajectory phases of vehicular collisions. These models consist of vehicle dynamic models, tire traction models and tire/road coefficient of friction models. The vehicle dynamic models developed include a two dimensional seven degree of freedom model with constant tire normal loads, a seven degree of freedom model with dynamic tire normal loads and a three dimensional ten degree of freedom model. The tire model is selected among more than a dozen tire traction models based on selection criteria developed in this work for reconstruction of vehicular accidents. Accuracy of this tire traction model is then evaluated with experimental tire data. Two tire/road coefficient of friction models are evaluated and a third is developed in this work. These models are compared with experimental data obtained from publications and friction tests conducted during this research. A series of violent maneuver tests were performed with instrumented passenger cars for the comparison of vehicle dynamic models and the overall evaluation of trajectory models. Sensitivity of the trajectory models to vehicle and tire parameters as well as tire/road coefficient of friction is also analyzed as part of this work.