The Measured Rolling Resistance of Vehicles for Accident Reconstruction

Abstract

<div class="htmlview paragraph">Knowledge about vehicle rolling resistance is required to calculate speed loss of accident vehicles during portions of their pre-impact and post-impact trajectory when they are not braking or sliding directly sideways. The accuracy of assumed rolling resistance values is most important in accidents with long post-impact roll out distances. Very little hard data are currently available<span class="xref"><sup>1</sup></span> and the accident reconstructionist must usually make estimates of drivetrain losses and normal and damaged tire rolling resistance to determine overall vehicle rolling resistance.</div> <div class="htmlview paragraph">In the first part of this study, the rolling resistances of various vehicles with different drive configurations are determined, based on accurate measurements made with a 5<sup>th</sup> wheel. In the second part, sensitivity analyses are done with PC-Crash<span class="xref"><sup>2</sup></span>, a computer simulation program, to determine what effect the error in assumed rolling resistance has on speed calculations for various types of post-impact trajectories.</div>