I-405 to close in both directions near SR 522 this weekend, Bothell expecting some gridlock

Bothell residents could be trapped in their neighborhoods the next two weekends as the state closes I-405 in both directions near SR 522.

The Washington Department of Transportation (WSDOT) is taking down the old ramp from northbound I-405 to westbound SR 522, and it needs to close the freeway to do it, as the ramp crosses both directions. The plan was to close the entire freeway from Friday night to Monday morning, but WSDOT thinks it can complete the work this weekend, from Saturday into Monday.

“We really wanted to try to keep traffic moving as much as we can, so the full closure will start at 6 p.m. on Saturday, March 7, and we’ll go until 4 a.m. on Monday morning,” Lauren Penning, the senior communications specialist with WSDOT, said.

All northbound traffic will be taken off the freeway at SR 522 and then back on the freeway at SR 522. Not too bad of a detour. Just an on and an off. But that detour won’t be ready when the closure starts on Saturday.

WSDOT wants to add a second lane to that northbound off-ramp to handle more cars.

“We’re going to be re-striping that ramp so that we can accommodate two lanes of traffic through the detour, which will really help keep that flowing a little bit better and help that detour route perform better,” Penning said.

Until that striping is finished, northbound drivers will be diverted to eastbound SR 522 to Woodinville and then back to I-405 via neighborhood streets to 195th.

The southbound detour is the one that has the potential to trap people in their Bothell neighborhoods. All southbound traffic will be diverted off I-405 at SR 527 in Canyon Park. Drivers will go through downtown Bothell and back to I-405 via eastbound SR 522.

That’s a lot of cars on a road that is only one lane in sections.

“We want to remind people, if they’re if they are taking that detour route, to be mindful that there are people living there,” Penning said. “Try not to block driveways. Pay attention to the uniformed police officers as they direct traffic in that area. We’re all trying to keep everybody moving as much as we can.”

Those uniformed officers will be directing traffic the entire time, but this is a place you’ll want to avoid.

“We are anticipating there to be about an hour delay at the peak times,” Penning said. “That’s really the best case scenario, if people make other plans, kind of stay away, try to do what they can to minimize the amount of traffic going through there. This is a really challenging, high impactful closure.”

Next weekend, drivers can expect the same delays, and the freeway will be closed from Friday night until Monday morning.

“The next weekend will be a little different,” Penning said. “We have a bigger section that we have to remove, and so those closures will start overnight on Friday and go until Monday morning. But we do have the opportunity to open southbound I-405 early on that second Sunday.”

What is WSDOT doing that it requires so much pain for the region?

It is building a new northbound I-405 bridge between the current freeway. The first 10 girders have already been put in place.

This will allow WSDOT to add a lane in each direction between SR 522 and SR 527. That lane will be added to the express toll system. The project also adds direct access ramps to the toll lanes from SR 522.

Construction should be complete 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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