Sequencing for Phases with Flashing Yellow Arrow

When the Utah Department of Transportation (UDOT) first implemented flashing yellow arrows (FYA) for left-turn phasing, high crash rates were observed with lagging FYA operations. As a result, current UDOT policy for FYA operations for protected/permitted left turn phasing is to not “lag,” meaning to allow the protected left turn phase to follow the opposing through movement, due to a “perceived yellow trap.” The purpose of this research is to evaluate current UDOT policies on leading/lagging left turn sequencing to determine if more flexibility could be provided, while still maintaining an acceptable level of safety. This will include reviewing the operation of FYA signal heads in other states, along with reviewing potential driver behaviors leading to the “perceived yellow trap.” The research will compare UDOT policies with other state DOT policies on leading/lagging left turns with FYA. Design and hardware factors will also be analyzed for safety impacts.

Language

• English

Project

• Status: Active
• Funding: $75,000.00
• Contract Numbers:

  268026

• Sponsor Organizations:

  Utah Department of Transportation

  Research and Innovation Division
  Salt Lake City, UT  United States  84114
• Managing Organizations:

  Utah Department of Transportation

  Research and Innovation Division
  Salt Lake City, UT  United States  84114
• Project Managers:

  Jensen, Travis

• Performing Organizations:

  Avenue Consultants, Incorporated

  6575 South Redwood Road,. Suite 101
  Taylorsville, UT  United States  84123
• Principal Investigators:

  Larson, Shawn

• Start Date: 20251007
• Expected Completion Date: 20270831
• Actual Completion Date: 0

Subject/Index Terms

• TRT Terms: Arrows (Signals); Flashing traffic signals; Left turns; State of the practice; Traffic safety; Traffic signal phases; Traffic signal timing
• Geographic Terms: Utah
• Subject Areas: Highways; Operations and Traffic Management; Safety and Human Factors;

Filing Info

• Accession Number: 01968452
• Record Type: Research project
• Source Agency: Utah Department of Transportation
• Contract Numbers: 268026
• Files: RIP, STATEDOT
• Created Date: Oct 13 2025 6:57PM