To address an increasing backlog of roadways in need of rehabilitation, the Illinois Department of Transportation (IDOT) began use of a standard overlay thickness policy in the early 1980s. On the non-interstate, or primary, system, first resurfacings or overlays over pavements being widened and resurfaced were allowed 2.5 in. (6.35 cm). Subsequent resurfacings were limited to 2 in. (5.08 cm). A provision in the policy allowed for exceptions. This report presents the results of an evaluation of the performance of bituminous overlays constructed on the primary system in accordance with IDOT's overlay policy. Twelve projects were selected for monitoring. The results of visual surveys, deflection testing, and Condition Rating Survey (CRS) histories were analyzed. The standard overlay thickness policy met the FHWA-required minimum 5-year performance period for Federal-aid rehabilitation projects on the primary system. Subsequent overlays were found to have shorter life spans than first overlays. Records of requests for exceptions to the standard overlay thickness policy were also reviewed. Information gathered from the records review was incorporated into the policy and used to create a more efficient process for reviewing requests for exceptions.
In the mid-1980s, the Illinois Department of Transportation (IDOT) found itself challenged to maintain an aging highway network at an acceptable level...
Prioritizing needs and targeting scarce highway funds are critical issues for highway officials. Highway engineers have many valuable tools to assess ...
Links with this icon indicate that you are leaving a Bureau of Transportation
Statistics (BTS)/National Transportation Library (NTL)
Web-based service.
Thank you for visiting.
You are about to access a non-government link outside of
the U.S. Department of Transportation's National
Transportation Library.
Please note: While links to Web sites outside of DOT are
offered for your convenience, when you exit DOT Web sites,
Federal privacy policy and Section 508 of the Rehabilitation
Act (accessibility requirements) no longer apply. In
addition, DOT does not attest to the accuracy, relevance,
timeliness or completeness of information provided by linked
sites. Linking to a Web site does not constitute an
endorsement by DOT of the sponsors of the site or the
products presented on the site. For more information, please
view DOT's Web site linking policy.
To get back to the page you were previously viewing, click
your Cancel button.
United States Department of Transportation
[PDF-1.65 MB]
