STUDY OF THE EFFECT OF TWO-WAY LEFT-TURN LANES ON TRAFFIC ACCIDENTS

The purpose of this investigation was twofold: (a) to determine the safety-effectiveness of two-way left-turn lanes (TWLTLs) and (b) to determine the cost-effectiveness of TWLTLs. The study includes statistical as well as economic analyses. Accident data were collected for 31 roadway sections, 15 five-lane and 16 three-lane sections, for 2 years before and 2 years after the improvements (addition of the TWLTL) were made. Statistical tests were applied on total accidents as well as affected accidents (rear-end, left turn, and sideswipes), their rates, and their severity. Statistically significant reductions were found in accidents, their rates, and their severity. An economic analysis was also performed, including benefit-cost ratios and cost-effectiveness values (cost per accident reduced). The only benefit considered was saving in accidents. The results of economic analysis along with those of statistical analysis indicate that the TWLTL is an economic safety improvement to the conventional two and four-lane urban roadways along which extensive commercial development has taken place.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1984/960/960-004.pdf
• Summary URL:
  • https://scholar.google.com/scholar_lookup?title=STUDY+OF+THE+EFFECT+OF+TWO-WAY+LEFT-TURN+LANES+ON+TRAFFIC+ACCIDENTS&author=J.+Thakkar&publication_year=1984
• 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

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  Washington, DC  United States  20001
• Authors:
  • Thakkar, Janak S
• Conference:
  • 63rd Annual Meeting of the Transportation Research Board
  • Location: Washington District of Columbia, United States
  • Date: 1984-1-16 to 1984-1-20
• Publication Date: 1984

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 27-33
• Monograph Title: GEOMETRICS AND SAFETY CONSIDERATIONS
• Serial:
  • Transportation Research Record
  • Issue Number: 960
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Benefit cost analysis; Cost effectiveness; Economic analysis; Highway safety; Highways; Impact studies; Improvements; Left turn lanes; Statistical analysis; Traffic crashes; Two way left turn lanes
• Subject Areas: Data and Information Technology; Economics; Highways; Operations and Traffic Management; Safety and Human Factors; I82: Accidents and Transport Infrastructure;

Filing Info

• Accession Number: 00391641
• Record Type: Publication
• ISBN: 0309037069
• Report/Paper Numbers: HS-038 211
• Files: HSL, TRIS, TRB
• Created Date: Aug 31 1985 12:00AM