Long-term behaviour model of skid resistance for asphalt roadway surfaces

Skid resistance (SR) is relevant to road safety. Several researchers have showed that SR diminishes its value over time depending on the traffic-aggregated interactions, and the presence of heavy vehicles in the traffic stream. The classical SR model shows that its value drops from a starting value to an equilibrium value over time. However, this behaviour in low-volume roads is not entirely true. In this paper, an SR model in a single mathematic specification is proposed, which considers the polishing effect of heavy traffic through the polishing equivalence factor. The model was calibrated by using data measured with a SCRIM device from 1100 test sections in Chile. Considering speed and temperature factors calibrated for Chile, data were processed and corrected. It was concluded that the model for long-term behaviour of SR is satisfactory, but it is necessary to include the seasonal effects for a more realistic model.