Analysis of the Influence of Vehicle Dynamic Parameters on Tire Marks

Tire marks play a central role in the reconstruction of traffic accidents, since they can provide valuable information about the vehicle's trajectory, initial speed, or the steering and braking input of the driver. The research project described in this paper focuses on the analysis of tire marks under controlled conditions using a monowheel setup to enable a selective variation of different vehicle dynamic parameters without mutual influence. The long-term goal is to find a model for the development of tire marks to predict the influence of specific vehicle dynamic parameters on the generation of tire marks. This model may be applied in accident reconstruction tools. A literature review has been performed to find evidence for the development of tire marks and to identify relevant parameters for their generation. Currently, no explicit physical or mathematical model showing the influence of tire forces or slip on the generation of tire marks is available. In the literature, it is often assumed that tire marks occur at the limit of traction. A physically motivated formula has been developed to calculate the friction force within the contact patch as a function of the tire forces, the longitudinal slip, and the side slip angle. The main hypothesis deduced from this formula is that the intensity of a tire mark depends on the magnitude of this friction force independent of the varying parameter. To verify this hypothesis, experiments have been conducted with variations in longitudinal slip, side slip angle, and tire type. First results agree with the model, showing a correlation between the intensity of tire marks and friction force, depending on the tribological and optical tire and road properties. This correlation is introduced as tire-marking sensitivity.