Development Of The Unsurfaced Roads Rating Methodology

A method for rating the surface drainage and conditions of unpaved roads has been developed, and a field manual has been prepared to assist county, municipal, military and township highway agencies in managing the maintenance of such roads. The types of distress found in unpaved roads are categorized and listed in the manual. For each type of distress listed, there is a description of the distress and the levels of severity, an illustration, and a measurement method. The manual also includes instructions on how to inspect unsurfaced road conditions, a field inspection work sheet, and a family of deduct value curves for the distress types and associated severity levels. The curves were validated using data gathered during seven field surveys throughout the United States. This report describes the development of the deduct value curves for the seven distresses identified in unsurfaced road maintenance. The development of the original curves and the adjustments after each field trip are described. The surface and drainage rating method and maintenance strategies can be used alone, or they can be adapted for use with any existing computerized pavement management system (PMS). The rating method and strategies are compatible with the PAVER PMS developed by the U.S. Army Corps of Engineers and the American Public Works Association. With appropriate software modifications, an unsurfaced roads component of the PAVER PMS will be available for use, giving local highway agencies a more comprehensive roadway management system. (SDW).