Flashing Yellow Arrow Traffic Signals

As the City  continues making strides in intersection and traffic signal safety, it seems some confusion has arisen, “Why am I not getting a green left turn signal?” To better understand why you may not be getting the green arrow to turn left at an intersection, here are the types left turn phases used at traffic signals:

1. A permissive left turn phase allows a driver to turn left when the signal turns green after yielding to both vehicles coming from the opposite direction. No green arrow is present.
2. A protected left turn phase allows a driver to turn left when given the green left turn arrow. This means that oncoming traffic has a red light and is unable to continue through the intersection while left turning drivers are protected. With a protected only left turn, drivers wanting to turn left are only allowed to do so when the arrow is green.
3. A permissive/protected left turn phase is a combination of both. When there is a left turn arrow, this the protected phase allowing left turning vehicles to turn while oncoming traffic still has a red light. After the left turn arrow turns red (then disappears), and the rest of the signal heads are green, left turning vehicles may make their turn after yielding to oncoming traffic and pedestrians.

The City's Traffic & Transportation Unit has received inquiries from residents wondering why they are not getting a left turn signal at newly upgraded intersections, like Mount Vernon Highway at Dupree Drive/Powers Ferry Road. This is because there is not a “Permissive/Protected” left turn phase, but a “Permissive” left turn phase.

As technology advances, so do our traffic signals. The City of Sandy Springs is moving away from the older signal head containing five bulbs, and installing the safer proven Flashing Yellow Arrow, or FYA . Flashing Yellow Arrows can have both a permissive left turn phase or a permissive/protected left turn phase.

The confusion we see frequently is that drivers assume since there is a Flashing Yellow Arrow, that there should also be a green arrow at some point. This is not the case. It is a lot like the analogy that a square is a rectangle, but a rectangle is not a square. Just because you see that an intersection has a Flashing Yellow Arrow, does not necessarily mean you will also get a green arrow. This is based on the demand, or volume, of left turns at a given location. Below is a list of examples of intersections (not limited to) that have Flashing Yellow where you will not receive a green left turn arrow:

• Mount Vernon Highway at Dupree Drive/Powers Ferry Road
• Mount Vernon Highway at Blue Stone Road
• Vehicles turning left from Belle Isle Road onto Roswell Road

We hope this clears up any confusion, and if you have any follow up questions feel free to reach out to Brendan Fitzpatrick, Traffic/Transportation Engineer at bfitzpatrick@sandyspringsga.gov or David Low, Senior Traffic/Transportation Engineer at dlow@sandyspringsga.gov.