Why does a left-turn signal go green when no cars are there?

Recently, this column answered a reader’s question about traffic signal timing on Broadway in Everett.

The timing there turned out to be a vestige of pre-coronavirus traffic congestion.

Questionable timing at a different set of Everett lights got the attention of another reader.

Howard Vining takes Everett Mall Way to I-5 every day. He noticed that “something seems wrong” at the intersection with Central Mall Drive, the glorified driveway to the Olive Garden’s new or old locations.

“No matter the time of day, the northbound/southbound signals will switch to left turns, even if there’s no cars waiting in the lanes,” he said. “It seems like it’s been happening every time since I’ve been paying attention, and seems like something that should not be happening on purpose …”

His keen eye was right. There is something wrong at that intersection.

Usually a vehicle detection loop — an electromagnetic sensor that registers when a vehicle drives over it in the road — triggers the signal. But it’s broken.

“We discovered that the vehicle detection loop for that left turn was damaged earlier this year,” Everett traffic engineer Tim Miller said in an email.

The fix will take a while. It’s not like checking the breaker box for a fuse that blew.

Everett staff can’t repair the damage, so a contractor is needed. Once that’s required, the city waits until there are several repairs for that one contract.

“To maximize our resources, we seek these services when we accumulate multiple repairs that can be made with the same contract,” Miller said. “While we don’t have a current estimated date of repair, we are hopeful that it will be repaired in the next several months.”

Everett’s traffic center stopped gathering data because of how abnormal flow is these days. Miller said traffic volumes generally are 40% to 50% below average. So fewer people are out and about, which may exaggerate the feel of time passing while waiting on a turn signal without any vehicles using it.

In the interim, the city changed the signal timing to decrease the delay. But until the sensor is repaired, the left turn will come on each cycle just in case a vehicle is there. After all, who would enjoy sitting at the left turn and not have it go green?

Have a question? Email streetsmarts@heraldnet.com. Please include your first and last name and city of residence.