Methodology for Evaluation of Seal-Coated, Gravel, and Dirt Roads

Friday, July 12, 2019 - 19:30

The objective of this research project was to develop methodologies for the evaluation of different types of seal-coated, gravel, and dirt roads by using a best-practice-oriented pavement-management system in Illinois. A statewide survey comprised of 13 questions collected 133 responses from county engineers and highway commissioners. Many counties and townships in Illinois performed similar practices to maintain seal-coated, gravel, and dirt roads. The subjective windshield surveys were often conducted on a weekly basis to identify the most common distresses, such as potholes, rutting, and roadside drainage. Several seal-coated, gravel, and dirt roads were evaluated using a field distress-survey manual method based on the newly developed Seal-Coated Road Condition Index (SCRCI)and an Unsurfaced-Road Condition Index (URCI) that was adopted to measure surface conditions of gravel and dirt roads. In addition, some of the commercially available cell phone applications ,or apps, were investigated for their effectiveness next to the use of a rolling or high-speed profilometer for assessing roughness conditions of seal-coated, gravel, and dirt roads in this research study. Future research is recommended to fully establish guidelines about the use of a cell phone app to be adopted by the Illinois Department of Transportation (IDOT)and for use by local agency officials in Illinois. In conclusion, this research project established a database to develop a best-practice guide for effectively evaluating unpaved roads maintained by local agencies. The full paper is online at


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