Determining the Prominence of Texture Scales on Road Skid Resistance

The work described in this paper contributes to the physical separation and systematic identification of the role of the small and large scales on skid resistance. A new signal processing technique termed Empirical Mode Decomposition (EMD) and a skid resistance model named Dynamic Friction Model (DFM) are synergized to evaluate the effects of the small and large road surface texture wavelengths on skid resistance data measured using current technologies (Dynamic Friction Tester (DFT) and Circular Track Meter (CTM)). The influences of the different wavelengths are investigated by first; applying the EMD to separate and synthesize the intrinsic texture scales to gradually and smoothly decompose the original surface textures, and second; to utilize the DFM with the synthesized texture profiles to analyze and discover their relative effects on measured friction. The obtained results show that for two road surfaces (in controlled wet conditions) with the same nominal large-scale texture range, the higher the small-scale texture is, the better the skid resistance will be at low speed. Furthermore, for two wet road surfaces with the same small-scale texture, the higher the large-scale texture is, the better the skid resistance is with increasing speed. In summary, on wet road surfaces, the small-scale texture is key to achieving good skid resistance at low speeds and large-scale texture is crucial to maintaining it when the speed increases.