Flashing Yellow Arrow

Granting Agency: Wisconsin Department of Transportation

Researchers: David Noyce (PI), Andrea Bill

Primary Project Objectives

This research focuses on the flashing yellow arrow (FYA) permissive left-turn indication in shared (bimodal) yellow
and green arrow signal sections. Left-turns at signalized intersections continue to be a significant challenge for
transportation professionals, from both a safety and operations standpoint. Navigating a left-turn can be a dangerous
maneuver for drivers to complete because of the requirement to simultaneously focus on several dynamic aspects of the
visual scene while crossing the opposing lane(s) of traffic as well as comprehending the meaning of the traffic
signal indication. Improving safety conditions for left-turning vehicles has the potential to significantly reduce
crash rates and improve signalized intersection safety.


The objective of this research was to analyze driver comprehension and driver behavior impacts of retrofitting
existing three- and five-section signal displays with the FYA indication. This objective was accomplished by
conducting a computer-based static study at various locations in Madison, Wisconsin and Amherst, Massachusetts. The
results from the study were analyzed to determine if the location of the FYA within any given signal display
arrangement had a significant impact on driver comprehension. In addition, other variables were analyzed to determine
if they had any impact on driver comprehension. These variables included the signal display arrangement, the thru
indication, the presence of opposing traffic, and demographics.

Driving simulator.