Q: I have noticed several left-turn signals that have been changed to blink yellow, allowing drivers to make the turn if there is no oncoming traffic. What needs to be done to implement this at the intersection of 104th and Canyon Road? — Judy V.
A: We here at Traffic Q&A headquarters are squeamish about making a left with a green arrow. Those flashing yellow ones scare us to death. Too many years in the news racket, perhaps.
Anne Radford, a spokesperson for Pierce County Planning and Public Works, explained the point of them.
“With the flashing yellow arrow, drivers are allowed to make a left turn after yielding to oncoming traffic, rather than having to wait until the signal cycles back to their left-turn green arrow phase,” Radford told us. “Pierce County follows Federal Highway Administration guidelines to determine if this operation would be beneficial at an intersection. To permit this maneuver, there must be adequate gaps in oncoming traffic, so motorists can make these left turns safely and efficiently.
“The addition of this phase type can reduce delays for motorists turning left.”
Precisely Judy’s point about 104th and Canyon.
“With the exception of rush-hour traffic, this intersection would be an ideal candidate!” she told us via email. “The left-turn signal is very short, usually allowing only three cars (if everyone is paying attention). The through traffic is very long. I think a blinking yellow turn signal would keep things moving along nicely in our area.”
Radford said the county has installed blinking yellows at 29 intersections and continues to evaluate locations.
“Coincidentally, the Canyon Road East and 104th Street East intersection was already on the list for evaluation, and data collection is being scheduled,” she said. “If we decide the operation should be added once the evaluation is complete, we will schedule the installation as soon as funding and materials are available.”
That pesky funding. What’s something like what Judy wants cost, Ms. Radford?
“The cost depends on how much components such as traffic control equipment, signal head modules (the arrow lights themselves) and pedestrian push buttons need to be upgraded in order to support the function,” Radford said. “It will cost around $15,000 to implement the Flashing Yellow Arrow indication at the 9th Street East and 180th Avenue East intersection by Lake Tapps.
“If we decide the Flashing Yellow Arrow indication should be added at Canyon Road East and 104th Street East, the cost would likely be not as much, but still would be about $5,000 at a minimum.”
That’s a bit of green.
Have a suggestion for a flashing yellow? Contact the county’s traffic team at email@example.com.