DELAY ALLEVIATED BY LEFT-TURN BYPASS LANES

The effectiveness of a left-turn bypass lane on a two-lane rural T-intersection shown by delay data was examined in this research. The bypass lane was a 12-ft-wide marked lane that through traffic may use to move around a vehicle that has stopped to make a left turn onto the minor road of the T. Delay data were generated by the TRAF-NETSIM traffic simulation program sponsored by the FHWA. Delay can be converted into driver cost, which can be compared with the cost of constructing the lane, to provide a good indication of the point at which the extra lane would be warranted. Seven factors that may affect the need for the extra lane were tested: the opposing through volume, the opposing right-turn volume, the through volume, the left-turn volume, vehicle speed, and the distance to the nearest upstream and downstream signal. The presence of a bypass lane was also tested to allow comparison between situations with and without left-turn bypass lanes. Sixty-four simulations were run to test the factors and the interaction among factors. The results indicated that the presence of a bypass lane was a significant factor in delay, especially when higher levels of opposing and left-turn volumes were present. Significant delay and percent stops savings can be realized by including a left-turn bypass lane in certain situations.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/trr/1991/1299/1299-001.pdf
• Record URL:
  https://scholar.google.com/scholar_lookup?title=DELAY+ALLEVIATED+BY+LEFT-TURN+BYPASS+LANES&author=E.+Bruce&author=J.+Hummer&publication_year=1991
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309051061
• Supplemental Notes:
  • This paper appears in Transportation Research Record No. 1299, HOV Facilities and Transportation Systems Management 1991. 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
• Authors:
  • Bruce, Edward L
  • Hummer, Joseph E
• Publication Date: 1991

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 1-8
• Monograph Title: HOV facilities and transportation systems management, 1991
• Serial:
  • Transportation Research Record
  • Issue Number: 1299
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Measures of effectiveness; Rural areas; Savings; Stopped time delays; T intersections; Traffic delays; Traffic simulation; Two lane highways
• Uncontrolled Terms: Effectiveness
• Old TRIS Terms: Left turn bypass lanes
• Subject Areas: Design; Highways; Operations and Traffic Management; Planning and Forecasting; I21: Planning of Transport Infrastructure; I73: Traffic Control;

Filing Info

• Accession Number: 00615761
• Record Type: Publication
• ISBN: 0309051061
• Files: TRIS, TRB, ATRI
• Created Date: Sep 30 1991 12:00AM