Selection of The Optimal Location of A U-Turn Bay for Vehicles Making Right Turns Followed by U-Turns

Florida increasingly uses restrictive medians and directional median openings on multilane highways to manage left-turn egress maneuvers from driveways onto major streets. As a result, drivers desiring to make direct left-turns from a driveway onto a major street would, instead, make Right Turns Followed by U-Turns (RTUT) at a downstream median opening or signalized intersection. This study evaluated the impacts of the separation distances between driveway exits and downstream U-turn bays on the safety and operational performance of vehicles making right-turns followed by U-turns (RTUT). With such results, the optimal location of a U-turn bay can be determined so that drivers have better access to make RTUTs. Two basic research approaches were applied in this study, including crash data analysis and travel time analysis. Crash data were investigated at 179 selected roadway segments, and travel time data were measured at 29 selected sites in the Tampa Bay area of Florida. It was found that the separation distance between a driveway exit and downstream U-turn bay significantly impacts the safety and operational performance of vehicles making right turns followed by U-turns. Based on the research results, the minimum and optimal separation distances between driveways and U-turn bays under different roadway conditions were determined to facilitate driver use of RTUT.


  • English

Media Info

  • Media Type: CD-ROM
  • Features: Figures; References; Tables;
  • Pagination: 16p
  • Monograph Title: TRB 86th Annual Meeting Compendium of Papers CD-ROM

Subject/Index Terms

Filing Info

  • Accession Number: 01049607
  • Record Type: Publication
  • Report/Paper Numbers: 07-1128
  • Files: TRIS, TRB
  • Created Date: Feb 8 2007 5:44PM