Visual Assessment System for Rating Unsealed Roads

Abstract

During the past decade the Wyoming Technology Transfer Center has developed two complementary guides for visually assessing unsealed roads. The Ride Quality Rating Guide (RQRG) assesses the quality of an unsealed road's ride as perceived by the traveling public. The Gravel Roads Rating System (GRRS) provides standard evaluations of seven distresses, including potholes, rutting, washboards, loose aggregate, dust, crown, and roadside drainage. These guides have been used by many individuals on several projects. The guides described in this paper have been revised, updated, and improved several times. Manual methods are better than automated systems for assessing the condition of unsealed roads because the conditions can change quickly and sensors provide a measurement only for the path or location on which they are placed. Some methods are too simplified, and others are so complex that they require excessive resources to perform. The RQRG and the GRRS rating systems were developed by combining the use of photographs that illustrate the various rating levels resulting from different types and combinations of distresses, rating of seven distresses, use of a rating scale of 1 to 10 (a rating of ≤ 2 equals failed; a rating of ≥ 9 equals excellent), and simplified data collection procedures. The guides described are based most directly on the pavement surface evaluation and rating (PASER) manuals produced by Wisconsin's Transportation Information Center. The primary source is the Gravel PASER Manual, which rates roads as failed, poor, fair, good, or excellent; assigns numerical values of 1 to 5, respectively; and incorporates many of the same distresses as the guides presented in this paper.