Abstract
Providing adequate skid resistance is essential for road safety. Many transportation agencies measure the skid number using a locked-wheel skid trailer at a reference speed (e.g., 40 mph). The skid number is often measured at lower speeds due to restrictions such as speed limit and road geometry. In addition, some interstate highways have a speed limit up to 80 mph and the skid measurements are collected at lower speeds (e.g., 40 mph) which could impose hazard to motorists. This study developed a statistical model to predict the skid number at a reference speed based on measurements of skid number at any operation speed between 20 and 60 mph. The predicted skid number is a function of the mean profile depth of pavement surface and skid number measured at any operation speed. The results demonstrated a strong correlation between predicted and measured skid numbers. This model can utilize the skid number measured at safe speeds, when field operations do not allow data collection at a reference speed to predict the skid number at a reference speed. In addition, skid resistance can be measured at higher speeds (e.g., 60 mph) and converted to a skid number at a reference speed which could improve the safety of operators and motorists.