Prediction of road surface friction coefficient using only macro- and microtexture measurements

This paper explains the prediction of road surface friction coefficient from macro- and microtexture parameters. Road sections on the Belgian road network with different road surface characteristics are chosen for friction, macrotexture, and microtexture measurements on the Belgian road network for analysis. This study comprises field testing and laboratory testing. In the first step of the field testing, the speed versus friction coefficient relation is established using the side force method. In the second step, macrotexture measurements are made by a laser profilometer. The last step of the field testing covers to take core samples for microtexture measurements. The laboratory testing consists of the establishment of a new microtexture measurement method called the new image analysis system. Finally, after statistically analyzing both measurements, a new model is founded to predict road surface friction coefficients from only macro- and microtexture at all speeds. Results show that at any speed there are strong effects from both macro- and microtexture on road surface friction.