The method of the friction diagram: New developments and possible applications

This paper presents an updating and an application of a tool developed by the authors: the Friction Diagram Method. The model on which the Friction Diagram is based was explained in previous papers and here it will be briefly summarized. A sensitivity analysis has been performed in order to establish which input parameters mostly influence the percentage of Friction Capital that a vehicle is using traveling on a given road layout with different boundary conditions. Furthermore, some possible applications of the Friction Diagram to real cases will be shown. In particular, the examples carried out show how the Friction Diagram, together with the speed and visibility diagrams, could be considered an important tool for selecting the speed limits of a road, both in dry and in wet conditions. The implications of the method provide some guidance for both the design of new road infrastructure and the improvement of existing roads.