A Contribution of the Analysis of the Road Macrotexture and Microtexture Roles vis-à-vis Skid Resistance

Skid resistance of roads enables drivers to shorten their stopping distances and to follow their desired trajectories on curves, too. The road texture remains the principal parameter governing skid resistance, especially in wet conditions. That texture is composed of a multitude of wavelengths with the microtexture and macrotexture considered to be the most important vis-a-vis to skid resistance. The present work contributes to the numerous analyses of the role of these two texture scales, as many authors have done before. It is based on the physical separation of these two scales of textures using an empirical mode decomposition and systematic identification of their roles on skid resistance using a dynamic friction model. The results found in this present work consolidate well the findings of previous works. Indeed, they show that the higher the microtexture is, the better the skid resistance will be at low speeds. Furthermore, the higher macrotexture is, the better the skid resistance is at high speed. These results have led to the proposal of algebraic relations linking skid resistance to microtexture and macrotexture at all speeds, constituting then a clear step forward compared to previous works.