Proposal of a New Method to Analyze the Road Safety Conditions Related to Friction

This paper represents a new method to analyze the problem of friction of road vehicles. Starting from the 3rd criterion of Lamm, the new concept of “Friction Capital” was introduced as the limit performance of the road in terms of friction. The method has been implemented in a software package called Design Skid Resistance (DSR), which reliability is tested providing the reconstruction of eight real skidding accidents. The output of the DSR is the Friction Diagram that represents the percentage of “Friction Capital” that a vehicle is using traveling on a given road. This percentage is defined as FUSED. During the design step, the Friction Diagram could be used in order to quantify the risk of skidding related to a given road layout. In this paper, the authors provide an example of DSR application to an Italian rural road, and investigate the influence of the vehicle type on the Friction Diagram, since it was observed that the type of vehicle used in analyzing a road segment makes the values of FUSED change when the boundary conditions and the road geometry change.