Abstract: The friction between vehicle wheels provided with rubber tires follows three influence curves (5, 6, 8). The friction between a wheel with rubber tire and a road surface is represented by a measuring result curve (1-4) the shape of which is determined symptotically from the rubber tire influence curve (6). Thus the measuring result curve (1-4) will have a characteristic shape with maximum values (1A-4A). The maximum friction is determined by the influence curve of the rubber tire and the road surface respectively, also denoted the maximum friction influence curve (8). Each influence curve has its mathematical model. In the mathematical model for the maximum friction influence curve (8) there is incorporated a slip speed, properties of the car tire and road surface-to-car tire properties. The car tire properties and the pavement-to-car tire properties can be determined as process parameters by measurement.