Research for AASHTO Standing Committee on Highways. Task 283. Evaluation of the Flashing Yellow Arrow (FYA) Permissive Left Turn in Shared Yellow Signal Sections

The National Cooperative Highway Research Program (NCHRP) project 3-54 (Evaluation of Traffic Signal Displays for Protected/Permissive Left Turn Control) recommended the use of the Flashing Yellow Arrow as the desired permissive indication for when using protected/permissive left turn (PPLT) phasing. The recommended display for the PPLT is a four section head. However, there are occasions where installing a four-section head can be very expensive or impossible without significant retrofit because of vertical clearance issues. It is possible to operate the flashing yellow arrow in PPLT in existing three section heads by installing a bi-modal head that allows the yellow left turn arrow to operate in flashing (permissive) and steady (change) mode. It is not known how well drivers will respond to this application of the three section head and whether it provides adequate notice that the permissive left-turn is ending, The primary purpose of this research is to explore the effectives of a three section protected/permissive left turn signal display versus a four section signal display, containing both a flashing yellow arrow section and a steady yellow arrow change interval section, when implementing the FYA in protected/permissive left turn control.


  • English


  • Status: Proposed
  • Contract Numbers:

    Project 20-07, Task

  • Sponsor Organizations:

    Federal Highway Administration

    1200 New Jersey Avenue, SE
    Washington, DC  USA  20590

    American Association of State Highway & Transportation Officials

    444 North Capitol Street, NW, Suite 225
    Washington, DC    20001

    National Cooperative Highway Research Program

    Transportation Research Board
    500 Fifth Street, NW
    Washington, DC  USA  20001
  • Project Managers:

    Derr, B

  • Start Date: 20090813
  • Source Data: RiP Project 23218

Subject/Index Terms

Filing Info

  • Accession Number: 01464128
  • Record Type: Research project
  • Source Agency: National Cooperative Highway Research Program
  • Contract Numbers: Project 20-07, Task
  • Files: TRB, RiP, USDOT
  • Created Date: Jan 3 2013 2:36PM