Cost-Effectiveness of Converting Signalized Arterials to Free-Flow Facilities

Traffic signals on four-lane divided signalized arterials impair mobility and exacerbate traffic congestion, driver frustration, crash risk, and overall user and community costs. This study examined the economic feasibility of converting this roadway type to free-flow corridors. A free-flowing facility does not refer to a freeway, but rather, a facility that is free of traffic control devices (such as traffic signals and stop signs) on the mainline. At the intersection level, four intersection alternatives were considered: signalized intersection (do nothing), two-way stop-controlled (TWSC) intersection, J-turn and interchange. The study developed a decision framework that evaluates the overall performance of upgrade alternatives at the intersection and corridor levels in terms of the total life-cycle agency and user cost associated with mobility and safety. It was found that when traffic volumes are low, the TWSC intersection has superior mobility performance over J-turn and signalized intersection. Interchange and J-turn exhibited superior safety performance compared to TWSC and signalized intersections. Interchange always has the highest mobility performance particularly where the major and minor road traffic volumes are high. The study also developed nomographs to present rankings of the alternatives and established decision boundaries based on major and minor road traffic volumes. The nomographs can help Indiana Department of Transportation (INDOT) identify the appropriate intersection type based mainly on the major and minor road traffic volumes. At the corridor level, the two conversion alternatives are free-flow corridor (with a mix of TWSC, J-turn and interchanges) and freeway corridor (interchanges only). Overall, the evaluation results were found to be sensitive to traffic volumes and weight ratio of the agency cost to user cost dollar. The study also developed a spreadsheet program to facilitate implementation of the decision support framework.

  • Record URL:
  • Corporate Authors:

    Purdue University

    Joint Transportation Research Program
    West Lafayette, IN  United States  47907-2051

    Indiana Department of Transportation

    100 N Senate Avenue
    Indianapolis, IN  United States  46204

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  United States  20590
  • Authors:
    • Qiao, Yu
    • Shellhamer, Nathaniel
    • Labi, Samuel
    • Fricker, Jon D
    • Sinha, Kumares C
  • Publication Date: 2019-9


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Final Report
  • Features: Appendices; Figures; Maps; References; Tables;
  • Pagination: 37p

Subject/Index Terms

Filing Info

  • Accession Number: 01745587
  • Record Type: Publication
  • Report/Paper Numbers: FHWA/IN/JTRP-2019/18
  • Contract Numbers: SPR-4226
  • Created Date: Jul 7 2020 10:13AM