The Need for a New Signal
The circular green indication takes on different meanings for different drivers. When a driver facing a circular green indication wishes to turn, he or she is required to yield to oncoming traffic and pedestrians. However, a driver traveling straight through facing a circular green indication is given the right of way.
In an effort to eliminate this dual meaning, the National Cooperative Highway Research Program conducted an extensive seven-year study and concluded that the flashing yellow arrow is the most easily understood indication for permissive turns. The display also maximizes signal timing flexibility which can improve safety and reduce delay.
Many jurisdictions have experimented with flashing signal indications for permissive left turns since the 1990s. The Federal Highway Administration approved the widespread use of the flashing yellow arrow in 2006 and adopted it as the new standard for permissive left turns in 2009. Texas made it the standard in 2011, and at least 43 states are currently using them.
The City's Traffic Engineering Department will install flashing yellow arrows at new and rebuilt traffic signals where permissive left turns are allowed. Flashing yellow arrows will also be retrofitted where appropriate at existing signals when traffic control equipment is upgraded or replaced.