ACCIDENT AND OPERATIONAL GUIDELINES FOR CONTINUOUS TWO-WAY LEFT-TURN MEDIAN LANES (DISCUSSION AND CLOSURE)

An investigation was begun to provide highway designers and traffic engineers with more definitive information on the installation of left-turn median lanes. Primary emphasis was on documentation of experiences with continuous two-way left-turn median lanes; however, for purposes of comparison channelized one-way left-turn median lanes (raised and flush markings) were included. This paper presents a summary of the detailed investigation of the literature on left-turn lanes, the results of a survey of current practices and standards in Texas, results of field studies, and guidelines for use. A literature survey and analysis of questionnaires returned by representatives from Texas cities and the Texas State Department of Highways and Public Transportation suggested areas in which definitive guidelines were required. Based on the analysis of these two phases of the study, field studies were conducted that concentrated on operational characteristics, accident experience, and currently accepted practices. The analysis of the data collected on left-turn-lane sites revealed many characteristics, patterns, and relationships of accidents and operational experiences. A brief summary of the conclusions and findings is included, and recommendations are provided to improve current practices. In the operational characteristics phase of the study, emphasis was placed on the lateral placement of vehicles in the left-turn lane and the entering and maneuvering distances of vehicles within the lane. These suggest the characteristics of driver behaviour that can be used by traffic engineers and highway designers in determining the optimum design elements for two-way left-turn lanes. (Author)

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1979/737/737-006.pdf
• Record URL:
  https://scholar.google.com/scholar_lookup?title=ACCIDENT+AND+OPERATIONAL+GUIDELINES+FOR+CONTINUOUS+TWO-WAY+LEFT-TURN+MEDIAN+LANES+(DISCUSSION+AND+CLOSURE)&author=C.+Walton&author=R.+Machemehl&author=T.+Horne&author=W.+Fung&publication_year=1979
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/03611981
• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Operational Effects of Geometrics. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Walton, C Michael
  • Machemehl, Randy B
  • Horne, Thomas
  • Fung, William
• Discussers:
  • Ring, Stanley L
  • Glennon, John C
  • Nemeth, Zoltan A
• Publication Date: 1979

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 43-54
• Monograph Title: TRAFFIC CONTROL DEVICES, GEOMETRICS, VISIBILITY, AND ROUTE GUIDANCE
• Serial:
  • Transportation Research Record
  • Issue Number: 737
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Design; Field studies; Guidelines; Left turns; Median lanes; Optimization; Road markings
• Old TRIS Terms: Optimum design; Traffic marking
• Subject Areas: Design; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00315066
• Record Type: Publication
• ISBN: 0309029929
• Report/Paper Numbers: HS-029 516
• Files: HSL, TRIS, TRB
• Created Date: Oct 8 1984 12:00AM