Changes in national and state safety standards have led to a new type of traffic signal in south Montgomery County: flashing yellow arrows.
The new type of signal on traffic lights means the same thing as the traditional green circle that indicates a person turning left needs to yield. However, the idea behind the change is to help drivers understand the turn is not protected and to keep traffic flowing more smoothly through the intersections, said Charles Cobb, traffic operations manager of Montgomery County Precinct 3.
"The flashing yellow arrow was implemented due to studies that several engineering firms and [the Texas Department of Transportation] and the Federal Highway Administration determined that this was actually safer," he said. "They felt that drivers paid more attention to a flashing yellow arrow rather than just the green ball."
The new type of turn light made its debut in Precinct 3 about six months ago after about two to three months of testing. But the idea of using flashing yellow arrows has been discussed nationally for several years, according to an FHA document.
"For many years, some engineers have had concerns that drivers turning left on a permissive circular green signal indication might inadvertently mistake that indication as implying the left turn has the right of way over opposing traffic," according to a Federal Highway Administration document dated March 20, 2006.
Cobb said the cost of the change is about $50 per LED light head that is installed along with personnel costs associated with switching the bulbs out. That money comes from the signal operations budget in Precinct 3. The switch has already had an effect on traffic flow, he said.
"It helped decrease the wait time and congestion along the main thoroughfares," he said. "Because if you have a break in traffic where it's safe for traffic to make the left turn, to yield on the left turn and complete the left turn, then that reduces the congestion on that left turn lane."
Nationwide, using flashing yellow arrows has become the standard, but its up to individual entities to follow the new guidelines. Several cities throughout Texas have begun using flashing yellow arrows, including Round Rock, Grapevine and Waco.
"It's dependent upon each entity," Cobb said. "But [each] commissioner's office will install this flashing yellow arrow at each intersection that is qualified for one within our precinct."
Those qualifications include factors such as sight distance requirements, he said. That means some intersections do not qualify, such as those with too much of a curve to see the signal from about 360–400 feet when traveling at 40 mph.
"The residents have been very open to the change, and they welcome the change and they wish we could put it at every single intersection," Cobb said.
