AURORA | In the most technical sense, drivers who pause for a few extra seconds at one of Aurora’s flashing yellow traffic signals are doing something wrong.
If they can safely make the left turn, they have every right to do so, and probably should, lest they test the patience of the honking horde gathering behind them.
But city traffic engineers are perfectly fine with those minor delays.
“That’s a failure we can live with,” said Anna Bunce, a project engineer with the city’s traffic department.
While the flashing yellow arrows might occasionally confuse drivers who aren’t accustomed to the fairly new traffic control devices, Bunce said that in the four years since the city installed its first flashing yellow near the Anschutz Medical Campus, the lights have worked well.
The lights, which are now in use at about 20 intersections around town, have been such a success that Bunce said they will likely be the standard traffic light whenever the city adds a new signal or upgrades an old one.
The lights work differently from standard left-turn traffic signals. Instead of a turn arrow with three lighted arrows — one red, one yellow and one green — they have four lights. The added light is a second yellow arrow that is capable of flashing.
During peak traffic flows, the light operates in a standard way, with left turns allowed only with a green arrow. But when traffic considerably thins — like late at night or on weekend afternoons — the lights are programmed to flash yellow.
That means if its safe to make the left turn, drivers are welcome to.
Bunce said the system beats sitting at a red light when there are no other cars coming the opposite direction.
The flashing yellow lights around town are programmed ahead of time to use the flashing capability when traffic will be slow and do not rely on a sensor installed in the road.
So far, Bunce said the complaints from motorists have been rare, and the complaints that come in tend to be from people who simply don’t like a new-fangled traffic light. Problems have been equally rare, Bunce said.
That’s partly due to the idea that even if motorists have never seen a flashing yellow before, they still know how to behave at the intersection; nearly every driver knows that yellow lights mean caution. Bunce said that means motorists who are confused err on the side of tapping the brakes and waiting for an extra second. They don’t motor through the intersection because they’re confused.
Aurora’s experience with the lights has mirrored what federal highway officials expected when they first certified the lights for use back in 2006. In a memo that year, the Federal Highway Administration said “motorists responded strongly and favorably to the concept with little or no public information; these highway users intuitively knew what the flashing yellow arrow meant.”
Bunce said drivers who might be a tad confused about the lights continue to be cautious, which is helpful.
“That’s not a bad thing,” she said.