Abstract
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). Due to some limitations (e.g., speed limit, road geometry), the skid number is often measured at lower speeds. In addition, some interstate highways have a speed limit up to 80 mph, yet the skid numbers are collected at lower speeds (e.g., 40 mph) which could impose hazard to motorists. This study developed a statistical model to describe the change in skid number with speed. This model can be used to predict the skid number at a reference speed (e.g., 40 mph) based on measurements of skid number at any operation and safe speed between 20 mph to 60 mph and mean profile depth of pavement surface. The results demonstrated good correlation between measured and predicted skid numbers. The developed model can be used to convert skid numbers measured at any operation and safe speeds between 20 mph and 60 mph to a skid number at a reference speed. In addition, this study developed a simple software to facilitate the calculations of skid number at any the desired speed. The software imports the texture and skid data collected using the pavement friction tester and calculates the skid number at a reference speed specified by the user using the developed model. The outcome of this study will improve the safety of the skid crew and motorists, in addition, it will expedite the skid data collection.
Keywords: Skid resistance, skid number, pavements, microtexture, macrotexture, skid truck, mean profile depth