Development of Left-Turn Lane Warrants for Unsignalized Intersections

Left-turn movements at intersections, including driveways—especially movements that are made from lanes that are shared with through traffic—cause delays and adversely affect safety. Although some left-turn warrants have been updated, many agencies still use research performed by M. D. Harmelink in the mid-1960s. Most states use procedures that are based on Harmelink’s work, but several limitations have been identified. Economic analysis can provide a useful method for combining traffic operations and safety benefits of left-turn lanes to identify situations in which left-turn lanes either are or are not justified economically. This project used a benefit–cost approach to determine when a left-turn lane would be justified. The steps included simulation to determine delay savings from installing a left-turn lane, crash costs and crash reduction savings determined from safety performance functions and crash modification factors available in the Highway Safety Manual, and construction costs. Left-turn lane warrants were developed for rural two-lane highways, rural four-lane highways, and urban and suburban roadways. In addition, warrants for bypass lanes were developed for rural two-lane highways.

• Record URL:
  https://doi.org/10.3141/2301-07
• Summary URL:
  http://scholar.google.com/scholar_lookup?title=Development+of+Left-Turn+Lane+Warrants+for+Unsignalized+Intersections&author=K.+Fitzpatrick&author=M.+Brewer&author=W.+Eisele&author=Y.+Zhang&author=J.+Gluck&author=H.+Levinson&author=V.+Iragavarapu&publication_year=2012
• Availability:
  • Find a library where document is available. Order URL: www.trb.org/Main/Blurbs/168307.aspx
• Authors:
  • Fitzpatrick, Kay
  • Brewer, Marcus A
  • Eisele, William L
  • Zhang, Yunlong
  • Gluck, Jerome S
  • Levinson, Herbert S
  • Iragavarapu, Vichika
• Publication Date: 2012

Language

• English

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 55–65
• Monograph Title: Operational Effects of Geometrics and Access Management 2012
• Serial:
  • Transportation Research Record: Journal of the Transportation Research Board
  • Issue Number: 2301
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Benefit cost analysis; Bypasses; Four lane highways; Left turn lanes; Rural highways; Streets; Two lane highways; Unsignalized intersections; Warrants (Traffic control devices)
• Subject Areas: Design; Highways; Operations and Traffic Management; Safety and Human Factors; I20: Design and Planning of Transport Infrastructure; I73: Traffic Control;

Filing Info

• Accession Number: 01366446
• Record Type: Publication
• ISBN: 9780309262996
• Report/Paper Numbers: 12-0182
• Files: TRIS, TRB, ATRI
• Created Date: Mar 29 2012 7:14AM