New traffic signal improves safety, efficiency
by Sarah Fay Campbell
A new kind of traffic light is coming to an intersection near you — well, eventually.
The Georgia Department of Transportation is installing 10 of the new "four section flashing yellow" left turn signals in Fayette County, and a total of 30 around the state, by spring. The flashing yellow has become the preferred option for many left turn lanes in new construction or when signals are upgraded.
There are no plans for the signals in Coweta, but they will likely be considered for future projects or upgrades.
In the new signal configuration, the flashing yellow arrow will replace the "left turn yield on green" indicator.
Drivers in left turn lanes will see one of four arrows: green, red, solid yellow, and flashing yellow. Red, of course, means no turn. The green arrow indicates one may turn freely. The solid yellow light indicates the light will soon turn red.
The newly placed flashing yellow light indicates drivers can turn left but must yield to oncoming traffic.
The new signals are expected to improve both safety and efficiency at intersections.
Studies completed by the Federal Highway Administration showed a “35 percent reduction in left turn collisions," said Grant Waldrop, regional traffic operations manager for the Georgia DOT.
"The belief is that the flashing yellow arrow is much easier to understand," Waldrop said. "Drivers, particularly older drivers, can get confused by a green ball on a left turn," and can end up turning when it is not safe to do so.
The "four section flashing yellow" signal was first listed in the "Manual on Uniform Traffic Control Devices" in 2009. The MUTCD is the Federal Highway Administration's book of standards and specifications for traffic signs, road makings and signals.
The city of John's Creek, Cobb County, and Dalton have already started using the signals.
In most cases, the four section flashing yellow lights will be for left turn lanes that previously had a green arrow plus the ability to turn left on green, if traffic is clear. This is known as "permitted and protected phasing."
Occasionally, though, the new signals will be installed in areas where drivers could previously only turn left on a green arrow. This is known as "protected phasing."
The first four-way light in Fayetteville, at Hwy. 314 and Banks Road, replaced what was a protected phasing intersection.
"Now we are able to allow permissive lefts, so drivers there are seeing a reduction in delays," Waldrop said. "I'm very excited with the results we have seen, just over the last couple of days."
If more drivers are able to turn left during the flashing yellow permitted phase of the light, the green arrow phase can be shorter — or even eliminated altogether, shortening wait time for all drivers.
In a typical case, the switch to the flashing yellow can actually allow more chances for left turns. Conversely, in times of heavy traffic at intersections, when turning left would be very dangerous, there might not be a flashing yellow phase at all.
"We can omit the flashing yellow arrow when traffic volumes are too heavy," Waldrop said. "Right now, we don't see the need for that in Fayetteville."
When drivers are using a left-turn lane with the four-way flashing yellow signal, it's important not to try and guess what the light is going to do.
"Follow the signal. Don't try to expect what is coming," Waldrop said.