Synthesis of Information Related to Highway Problems. Topic 46-12. Converting Paved Roads to Unpaved

Current transportation asset management practices assume that roads will either be preserved in their current structural condition or improved to enhance the structural condition. As well, the historic trend is to reduce the number of unpaved system lane-miles. These policies were developed in the last century when both the cost of asphalt and the cost of fuel were low compared to current costs, and the axles loads carried on rural low-volume roads were relatively light. In the past few years, the increased costs of construction and maintenance in combination with insufficient Federal, State, and local funding have resulted in a situation where asset managers are converting the pavements on aging rural roads to unpaved. In addition, failing to maintain a paved surface may lead to degradation in its ability to safely function as the surface becomes rough and slows down the average speed of traffic. At some point, the safe speed will become less than that attainable on a maintained unpaved surface. Local road departments are the most affected by the funding shortfall, as can be evidenced by the increasing amount of news media coverage of the practice. With the costs of maintenance and rehabilitation of aging pavements increasing, continuously shrinking budgets, and increasing loads from agricultural, energy, and freight sectors, the practice of converting pavements to unpaved will continue to grow. These issues make it necessary to identify measures to analyze and objectively determine when to convert to an unpaved surface, and to identify appropriate unpaved road maintenance and management strategies that will cost-effectively keep these converted pavements in a better condition than the original distressed asphalt pavement. Therefore objectives of this synthesis are: (1) to discuss and summarize what is meant by "low volume road" and "unpaved" in different circumstances, (2) to identify agencies that have converted or plan to convert roadways, (3) to identify metrics available to quantify the impact and legal liability of reduced maintenance due to lack of funds, (4) to identify the tools like databases, software, and other instruments that have been effectively used to determine when to convert a paved or hard surfaced road to unpaved surface, (5) to synthesize current decision parameters for asset management for low volume assets, including but not limited to- (a) Traffic volume and classification, (b) Environmental factors, e.g. air quality, water quality, soil contamination, (c) Initial cost vs. life-cycle cost; (d) Public policy concerns, (e) Safety issues, (f) Current pavement condition, (g) Available resources, and (h) Purpose of road (6) to identify documented and undocumented procedures used for converting/recycling pavements based on the type of pavement, (7) identify the state-of-the-practice for design and construction of unpaved roads (crown change ditching, chemical stabilization, dust control, maintenance requirements, etc.), (8) to identify and document proven procedures for providing design parameters on unpaved road preservation and maintenance projects, (9) to identify the impacts of the conversion, including, but not limited to--(a) public reaction, (b) changes in traffic patterns, (c) changes in agency equipment and staffing, (d) environmental impacts; (e) safety, (f) maintenance costs, (g) lessons learned, (10) to identify gaps in knowledge and research needs .


  • English


  • Status: Active
  • Contract Numbers:

    Project 20-05, Topic

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590

    American Association of State Highway & Transportation Officials

    444 North Capitol Street, NW, Suite 225
    Washington, DC  United States  20001

    National Cooperative Highway Research Program (NCHRP) Synthesis

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC    20001
  • Project Managers:

    Williams, Jon

  • Performing Organizations:

    Montana State University, Bozeman

    214 Cobleigh Hall
    Bozeman, MT  United States  59717
  • Principal Investigators:

    Fay, Laura

  • Start Date: 20140930
  • Expected Completion Date: 0
  • Actual Completion Date: 0
  • Source Data: RiP Project 37606

Subject/Index Terms

Filing Info

  • Accession Number: 01543395
  • Record Type: Research project
  • Source Agency: Transportation Research Board
  • Contract Numbers: Project 20-05, Topic
  • Files: TRB, RiP
  • Created Date: Nov 14 2014 1:00AM