2024 Volume 29 Issue 1 Pages 13-24
Historically, forensic scientists have used the model proposed by John Searle in 1983 to estimate the car impact speed using the throw distance of a cyclist in an accident reconstruction. However, it has not been verified whether the Searle equation originally developed for application to pedestrian accidents can be accurately applied to bicycle accidents. Furthermore, it was designed to calculate only the lower limit value instead of requiring no variable input of the projection angle that cannot be observed. These issues have long been concerns for the forensic scientists who conduct accident reconstruction for the purpose of proving the facts of a crime.
Therefore we developed a new model for estimating the car impact speed in bicycle accidents using the throw distance of the bicycle and the cyclist. Our model was designed to enable the setting of the projection angle and to calculate the upper and lower bounds so as to include the true value, based on the original equation of the Searle equation. We further verified the suitability and interpretability of the proposed model using data from previously reported crash experiments. Thus the proposed model was consistent with the experimental data, considering the variability of the crash test data, and properly simulated the post-crash motion of the bicycle.
This research will contribute to widen the scope of the inference in the scene of accident reconstruction in forensic science by providing two independent equations for estimating the car impact speed using the throw distance of the bicycle and the cyclist.
