Pavement rutting is a problem that has unknown consequences from a safety-based point of view. It is assumed that the wheel path fills with water in wet-weather situations, thus increasing the potential for a vehicle to hydroplane. The purpose of this study was to quantify how pavement rutting affects accident rates and to evaluate possible safety-based quidelines for the treatment of pavement rutting. A literature review was conducted to gain insight into the problem and to assist in developing an appropriate experimental design. Rut depth, traffic volume, and accident databases maintained by the Wisconsin Department of Transportation for undivided rural highways were then analyzed to identify statistical trends and relationships. Accidents were categorized as rut-related if the prevailing conditions could be potentially associated with the occurrence of hydroplaning. Rut depth measurements were average values for both directions of 0.16 km (0.1 mi) segments, and represent the average elevation difference between the tyre paths and the high point between them. The results of the statistical analyses indicated that the defined rut-related accident rate begins to increase at a significantly greater rate as rut depths exceed 7.6 mm (0.3 inches). Potential accident reductions associated with reductions in the relative amount of rutted pavement were also examined in the context of possible rut treatment guidelines. (A)
Abstract