Sullivan: I-405 expansion to widen freeway in Bothell is underway

We’ve all seen the Interstate 405 (I-405) expansion between Bellevue and Redmond, but construction to widen the freeway north of Bothell is now underway as well.

The state is widening both directions of 405 from about 160th at the north end of Kirkland to Highway 527 in Canyon Park. The new lane in each direction will be added to the existing one-lane express toll lane.

This spot is where my kazoo got its start because the tolls could not keep up with the amount of cars on that stretch of I-405. The toll lane continues to hit the $15 max nearly every day there because it’s so crowded.

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This expansion will also come with a redesigned 405/522 interchange to help manage the flow there. The Washington Department of Transportation’s (WSDOT) Craig Smiley said there isn’t a lot of room to make huge changes there.

“That interchange at 522 has a lot of constraints,” he said. “There’s a lot of flyover bridges and different things going on there. You got the Sammamish Slough, so it’s really a challenge to get additional capacity through there.”

But WSDOT plans to move some of those ramps. Drivers have noticed all the trees being removed on the east side of the freeway recently.

“We’ll be adding additional capacity from that northbound to eastbound ramp that’s been a challenge for a long time,” Smiley said. “That will have some additional capacity there and hopefully help out with that movement.”

Contractors will also be doing some other work on the corridor as well.

“We’re taking care of some of those culverts that don’t allow fish to go underneath the freeway,” Smiley said. “That’s a pretty big part of the project, and it also builds structures and bus rapid transit stations so infrastructure to support Bus Rapid Transit.”

To make this all happen, there are going to be a bunch of road and ramp closures during the project. The first was last weekend. There will be another one this weekend on Highway 522.

WSDOT’s Lauren Penning said all eastbound lanes near 405 will be closed to create a work zone.

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“It’ll be 10 p.m. on Friday, April 19 to 4 a.m. Monday, April 22,” she said. “We’ll have all eastbound 522 closed and one lane of westbound right by the I-405 interchange there.”

For drivers heading east out of downtown Bothell who want to head into Woodinville, you’re going to have to use a detour to get there.

“Drivers heading eastbound will be detoured off onto southbound 405 to take the northeast 160th street exit,” Penning said. “You will cross over the freeway and then get on north 405 and continue at the 522 interchange.”

Don’t expect much relief over the short term. This $834 million expansion isn’t set to finish until 2028.

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