Towards real-time skid resistance forecast

For any given road layout or curvature skid resistance as property of pavement surface and tyre is a decisive factor limiting the speed threshold for safe driving. Skid resistance is no fixed value and is significantly lowered in case of precipitation depending on form and rate. A further influence factor in such cases is the macro texture of pavements due to their capacity to hold precipitation while maintaining contact with the tyre. Snow and ice on roads are the main factors for lowered skid resistance resulting in elevated road accident levels and economic costs. With new methodologies in weather forecasting and RWIS – sensors better winter forecasting models for winter maintenance are already available. These current models consider different road materials mainly in order to specify parameters for solar flux absorption in energy budget calculations for real time road surface temperature estimation. The main emphasis of the paper lies in a determination of the impact of macro texture and amount of snow and ice on skid resistance of flexible and rigid pavements. Based on extensive field and laboratory research a connection between different texture and skid resistance determination methods could be established. The field tests consisted of film thickness and skid resistance measures among others for different weather situations. In the complementing laboratory tests the road surface texture was determined using high precision laser scanning on sample cores as well as other test methods. Based on the findings a real time skid resistance prediction for an entire road network becomes feasible.