ADDITIONAL LOST TIME CAUSED BY PERMITTED LEFT TURNS

Permitted left-turn phasing is commonly used to increase capacities and reduce delays at signalized intersections. But, under heavy traffic volumes, when they can only be made after the green, permitted left turns interfere with the start of subsequent phases, increasing the lost times and reducing the capacities of these phases. The primary objective of this research was to determine the additional lost time caused by permitted left turns. Additional lost times of protected left-turn phases, which were caused by cross-street permitted left turns, were measured at three signalized intersections. Multiple regression analysis of these data determined that the additional lost time depended on the number of permitted left turns made at the end of the cross-street green and the grade of the exclusive lane from which the protected left turns were made. The effects of the additional lost time on intersection capacity were evaluated. The results of this research provide a means of acounting for these effects in the analysis and design of signalized intersections.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1987/1112/1112-006.pdf
• Record URL:
  • https://scholar.google.com/scholar_lookup?title=ADDITIONAL+LOST+TIME+CAUSED+BY+PERMITTED+LEFT+TURNS&author=P.+McCoy&author=U.+Navarro&publication_year=1987
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309044642
• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Highway Capacity and Quality of Service. 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:
  • McCoy, Patrick T
  • Navarro, Ulises
• Publication Date: 1987

Media Info

• Media Type: Print
• Features: References; Tables;
• Pagination: pp 39-44
• Monograph Title: Highway capacity and flow theory and characteristics
• Serial:
  • Transportation Research Record
  • Issue Number: 1112
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Highway capacity; Intersections; Left turn phase; Multiple regression analysis; Signalized intersections; Slopes; Traffic delays; Traffic volume
• Uncontrolled Terms: Grade (Slope); Intersection capacity
• Old TRIS Terms: Left turn phasing; Multiple regression
• Subject Areas: Highways; Operations and Traffic Management; I71: Traffic Theory;

Filing Info

• Accession Number: 00465544
• Record Type: Publication
• ISBN: 0309044642
• Files: TRIS, TRB, ATRI
• Created Date: Feb 29 1988 12:00AM