Two Tacoma intersections back up traffic badly. What can be done to fix them?

Question: I’ve lived in the area for 22 years and have seen traffic get much worse across the area, but two intersections near each other on South Orchard Street have gotten really bad recently and need attention. What can be done to fix them? — Robert C., University Place.

Answer: The intersections are where Orchard Street meets South Center Street and where it meets South 19th Street. Both are beset by the same problem: Traffic backs up because of people trying to turn right while going north, in part because drivers have to stop before right on red lights. This only gets worse during the evening commute.

Helpfully, Robert offered a solution to these backups: add a green light for people turning right while cross traffic is turning left.

“During the light cycle, there is a long light that permits a protected left turn from westbound Center to southbound Orchard and from westbound 19th to southbound Orchard (in both cases there are two left turn lanes!),” Robert wrote. “During this extended protected left onto southbound Orchard, there is no need for right turning northbound Orchard traffic to stop and see if it safe to turn right on red.”

Equipped with this information, I asked city of Tacoma traffic engineer Josh Diekmann about fixing the Orchard backups.

Robert’s suggestion of allowing right turns while protected by left turns from the opposite part of the intersection is called a right-turn overlap, and they’re used frequently in busy intersections to make them more efficient.

“The Orchard Street intersections at Center and South 19th are good examples of older intersections where right-turn overlaps could be helpful,” Diekmann said.

The cost of adding right-turn overlaps depends on how new the existing traffic signal hardware is. If it’s new enough, Diekmann said, it’s as simple as a new light and some tweaks to wiring and software.

At older intersections, decades-old signal equipment would take tens of thousands of dollars worth of upgrades to be capable of right-turn overlaps. At that point, Diekmann said, the city seeks grants or other additional funding to make the upgrades.

Diekmann cited the intersection of 19th and South Mildred streets as a success story for right-turn overlaps, and noted the intersection’s signals were redone thanks to grant money.

Tacoma has recently acquired more grants to upgrade intersections along Pacific Avenue, South Tacoma Way and Portland Avenue East, Diekmann said. Those projects are taking priority, which is creating a backlog of potential signal improvements elsewhere in the city.

Unfortunately for Robert, it might be a little while before city engineers get to the Orchard Street intersections. But his question has gotten the intersections on the city’s radar screen for future evaluations.

If you have an intersection in Tacoma at which you’d like to see upgrades, contact city signal engineer Justin Belk at 253-591-5404.

This story was originally published August 5, 2018 at 9:17 AM.