Friction of Rubber Wheels on Wet Asphalt Surfaces

A reliable online prognosis of the grip between tire and road is a feature with a big potential for further improvements of the automotive safety. Existing grip potential prognosis systems for wet conditions are able only to describe the hydrodynamic decrease of friction at high speeds which depends on vehicle velocity, water film thickness and drainage properties both of the road surface and the tire. The present work deals with the friction at low speeds which depends on the road micro roughness. The experimental investigations are done in laboratory using a small solid rubber wheel and several asphalt samples. All parameters possibly influencing the friction process are varied. The influence of the test surface is found to be related to the micro texture and to be independent of any other parameters.