ROAD ACCIDENT RECONSTRUCTION: THE ROLE OF THE INERTIA PROPERTIES

The reconstruction of car accidents is a critical step in understanding the causes of an accident and, in case, for attributing responsibilities. Therefore, the reconstruction must be realized by considering all of the possible sources of error and misrepresentation. Since such activity relies on dynamic models of the colliding vehicles, mass properties (mass, centre of gravity location, inertia tensor) play a crucial role. The present papers aims to quantify the requirements in the knowledge of the inertia properties for a proper reconstruction of car accidents. The analysis is performed with reference to the case of two colliding vehicles. After a detailed description of the model employed for the reconstruction, dynamic simulation are utilized to assess the required accuracy, with particular reference to the effects of the uncertainty in mass, longitudinal location of the centre of gravity and yaw moment of inertia. It turns out that even relatively small errors in the definition of such parameters can lead to large errors in the reconstruction of the state of the colliding vehicles before the accident. Also, the variation in the inertia properties of the vehicles due to the crash is investigated. Engineers involved in car accident reconstruction should be aware of the importance of correctly estimate the inertia properties of vehicle, both before and after the accident, to obtain a correct estimation of the actual dynamic of the accident.