Potential Safety Cost-Effectiveness of Treating Rutted Pavements

Abstract

Pavement rutting is a problem that has unknown consequences from a safety-based point of view. It is assumed that the wheelpath fills with water in wet-weather situations, thus increasing the potential for a vehicle to hydroplane. A study was conducted to quantify how pavement rutting affects accident rates and to evaluate possible safety-based guidelines for the treatment of pavement rutting. Rut depth, traffic volumes, 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 1.8-km (1.1-mi) segments and represent the average elevation difference between the tire 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 in.). The cost-effectiveness of potential accident reductions associated with reductions in the relative amount of rutted pavement was also evaluated.