SELECTION CRITERIA FOR LEFT-TURN PHASING, INDICATION SEQUENCE, AND AUXILIARY SIGN. FINAL REPORT

The report documents the development of guidelines and recommendations for the selection of the left-turn phasing, indication sequences and auxiliary signs. The guidelines developed are based on field studies of over 100 intersections in nine Texas counties and utilize easy to obtain data for the selection process. A three-level decision process regarding the suitability of left-turn phasing treatment to be used is established. The process favors the least restrictive permissive left-turn phase unless traffic and geometric conditions warrant the more restrictive protected/permissive or protected only phasings. The guidelines developed are based on threshold values designed to determine what constitutes an "excessive" value for any particular decision variable beyond which more restrictive left-turn phasing treatments may be justified. Recommendations concerning signal indications and auxilliary signs are made based on delay, safety and degree of motorists' understanding. The study results show that selection of any particular phasing is a multi-objective process involving a number of factors, and in many cases more than one condition must be met to justify the selection of a particular phase to ensure an optimum solution.

• Corporate Authors:

  University of Texas, Arlington

  Department of Civil Engineering, P.O. Box 19308
  Arlington, TX  United States  76019-0308

  Texas Department of Transportation

  Transportation Planning Division, P.O. Box 5051
  Austin, TX  United States  78763

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Asante, S A
  • Ardekani, S A
  • Williams, J C
• Publication Date: 1993-2

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 155 p.

Subject/Index Terms

• TRT Terms: Decision making; Exclusive permissive phasing; Exclusive phasing; Field studies; Guidelines; Left turn phase; Permissive phasing; Recommendations; Signalized intersections; Traffic delays; Traffic safety; Traffic signal indications
• Old TRIS Terms: Auxiliary signs; Left turn phasing
• Subject Areas: Highways; Operations and Traffic Management; Research; I73: Traffic Control;

Filing Info

• Accession Number: 00628885
• Record Type: Publication
• Report/Paper Numbers: FHWA/TX-91/1256-1F, Res Rept 1256-1F, RSN 8-18-91-1256-1F
• Contract Numbers: Study 8-18-91-1256
• Files: TRIS, USDOT, STATEDOT
• Created Date: Apr 22 1993 12:00AM