Free-flow no more: Traffic signals coming to SR 522 at I-405 interchange

You thought drivers got upset when the state added traffic lights on the ramps between I-90 and I-5 in Seattle? Just wait until drivers find active traffic lights on State Route 522 (SR 522) Monday during their trips between Woodinville and Bothell.

Drivers have been asking me for weeks about the new signals being added to SR 522 at the I-405 interchange. They were curious why the Washington State Department of Transportation (WSDOT) would add signals to what was a free-flowing road. They were not happy about the change, but it’s coming Monday.

That’s when WSDOT will turn on two new traffic signals and open a new ramp from northbound I-405 to SR 522. This is all part of the expansion of the express toll lane system and increasing direct bus service to Bothell.

Big change for drivers near Woodinville, Bothell

The biggest change for drivers will be those going from northbound I-405 to westbound SR 522. Today, you have a free-flowing fly-over ramp. Come Monday, that fly-over ramp will close, and drivers will exit at a new off-ramp down to a traffic signal at SR 522. You will then wait at a signal to make a left turn to go westbound. This new signal will also stop both directions of SR 522 between Woodinville and Bothell, ending the free-flowing trip there.

If your destination is Woodinville from the northbound I-405, you will continue to use the existing ramps. No signal is being added there.

The other big change is for southbound I-405 drivers who want to hit eastbound SR 522 to Woodinville. You will use a new off-ramp and head down to a signal at SR 522. The fly-over ramp there, which provided a free-flowing drive, will be taken down.

Southbound I-405 drivers heading to Bothell will use the same exit as today.

To strip this down to the absolute bare bones, two stop lights are being added to SR 522.

You might ask why WSDOT is doing this.

In a recent blog post, WSDOT explained this will save budget and time for construction. It said it will make travel more efficient. It estimates that even during peak hours, the changes will likely only add about a minute to your trip. I drive that area frequently. I expect this to add a lot of time and create huge backups. We’ll just have to wait and see.

This isn’t the end of the construction. WSDOT will add a third signal in the area to tie into the express toll lanes. That should happen in 2028.

Chris Sullivan is a traffic reporter for KIRO Newsradio. Read more of his stories here. Follow KIRO Newsradio traffic on X.

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