Physical and empirical models for motorcycle speed estimation from crush

Abstract

This paper presents a new physical model for estimating motorcycle speed in motorcycle to car collisions from the motorcycle wheelbase reduction and car deformation depth. This model combines previously published specific energy characteristics of motorcycles and scooters derived from barrier tests with a motorcycle to car interface Force–Balance approach to estimate the collision energy absorbed by the car. This Force–Balance approach and three previously published models for motorcycle speed estimation are compared using a data-set of 107 published staged collisions, over a collision speed range of 30–122 kph. The Force–Balance model and a previously published empirical model were shown to compare well with the available staged tests, with statistically insignificant mean residuals of 0.8 and 0.7 kph for the predicated speed when compared with actual speeds. The corresponding standard errors were 10.3 and 11.2 kph, respectively. Two other previously published physical models were shown to significantly under-predict speed, with mean residuals of 5.6 and 19.5 kph, respectively, with corresponding standard errors of 9.5 and 11.8 kph. An analysis of impacts into hard and soft areas of the car sides show that the presented Force–Balance model is robust when applied to both soft and hard impact locations, while the empirical approach is shown to be robust for soft impact locations but under-predicts collision speed by a mean of 3 kph for hard impact locations.