Operational and Safety Impacts of Directional Median Opening on Urban Roadways: A Case Study in Houston, TX

As a design alternative for a median opening, directional median openings are normally used to restrict crossing and left-turn movements from minor streets to help avoid potential traffic conflicts. While this alternative may provide significant potential for safety benefits, its effectiveness is affected by a series of factors, such as geometry, traffic control, environmental conditions, and the type and placement of the downstream U-turn provisions. Inappropriate use of directional openings can result in extended travel time and worsened operations for minor streets, while providing very limited safety benefits for the whole corridor. The goal of this research was to investigate the operational and safety impacts of directional median openings on urban roadways. For this purpose, a case study was conducted on a 3,000-ft corridor on Jones Road in Houston, Texas, where four full median openings have been installed. The analysis of historical crash data and simulation-based analysis were conducted to investigate the performance of directional median openings compared with full median openings at the corridor. The results of this study showed that full openings should be avoided in the functional areas of signalized intersections and that the use of directional openings significantly reduced crossing-traffic conflicts at the opening locations, while slightly increasing lane-change conflicts in both the downstream and upstream areas. It also was found that use of directional openings may increase the congestion levels at the signalized intersections on the rerouting path.

  • Supplemental Notes:
    • This paper was sponsored by TRB committee AHB65 Operational Effects of Geometrics. Alternate title: Operational and Safety Impacts of Directional Median Opening on Urban Roadways: Case Study in Houston, Texas.
  • Corporate Authors:

    Transportation Research Board

    500 Fifth Street, NW
    Washington, DC  United States  20001
  • Authors:
    • Qi, Yi
    • Chen, Xiaoming
    • Liu, Guanqi
    • Wang, Yubian
  • Conference:
  • Date: 2014

Language

  • English

Media Info

  • Media Type: Digital/other
  • Features: Figures; References; Tables;
  • Pagination: 18p
  • Monograph Title: TRB 93rd Annual Meeting Compendium of Papers

Subject/Index Terms

Filing Info

  • Accession Number: 01516037
  • Record Type: Publication
  • Report/Paper Numbers: 14-4162
  • Files: PRP, TRIS, TRB, ATRI
  • Created Date: Feb 26 2014 12:40PM