Ramp removal at the I-405/SR 522 Interchange will be “Olympic” feat over four weekends

By Lauren Penning

UPDATE Feb. 10: Due to the complexity of the ramp removal, the team identified the need for more time to analyze the final removal plans and earlier construction dates were postponed. We are ready to start ramp removal Feb. 20. See below for schedule updates.

Crews are ready to begin removing ramps at the I-405/SR 522 Interchange starting Feb. 20. This “Olympic” feat will bring the project one step closer to widening

I-405 in Bothell as part of the I-405/Brickyard to SR 527 Improvement Project.

While you’re watching the wrap up of the games, our contractor crews will begin working hour by hour to remove these ramps. This is careful and complex work.  To do it safely, we must fully close roads during removal. Here is the current schedule:

• Feb. 20-21: partial weekend closure of westbound SR 522 at I-405
• Feb. 27 – March 2: weekend-long full closure of eastbound and westbound SR 522 at I-405 
• As early as March 6-9: weekend-long full closure of northbound and southbound I-405 through Bothell
• As early as March 13-16: weekend-long full closure of northbound and southbound I-405 through Bothell

These closures will have region-wide impacts. Best case scenario we estimate there will be one hour-long backups. This is your notice to plan ahead, use alternate routes and allow extra travel time. 

This is your notice to plan ahead, use alternate routes or allow extra travel time.

Why do we need to remove the ramps?

We need this space to build a new northbound I-405 bridge through the interchange. Some of the existing ramps we’re removing sit right where the new bridge and ramps need to go. This work will allow us to add one new express toll lane (ETL) in each direction and build direct access ramps to the ETLs.

Completing the dual express toll lanes and direct access ramps in this area will:

• Improve speed and reliability for Bus Rapid Transit and HOV users.
• Give drivers an additional choice when they need it.
• Benefit all lanes by helping us better manage the system.

Looking north at the I-405/SR 522 Interchange. We will remove the ramps highlighted in orange to create space for expanding the center of I-405.

Why do we need full weekend closures of roadways?

One of these existing ramps spans both I-405 and SR 522 and is sandwiched between three bridges. There is an interchange ramp above it that we are keeping. There are also the northbound and southbound I-405 bridges below it.  Bridge columns are also close and in between the northbound and southbound lanes. For public safety, we must close roadways during removal. We also have to protect the bridge deck underneath. This means as we work, crews will strategically remove pieces of the bridge deck and carry them away so we don’t add extra weight or impact the roadway below. The complexity of removing sections means the removal will take time so we have sequenced work over four weekends. 

Here is a view of the sections of ramp that will be removed each weekend. Crews will use specialized heavy equipment and follow a detailed schedule to complete the work safely.

What about traffic impacts?

These weekends will be difficult for travel. Detour routes can’t smoothly handle the normal amount of traffic from SR 522 or I-405.

At the same time, northbound I-5 through Seattle remains reduced to two lanes with the express lanes running northbound for Revive I-5 work. This limits northbound travel options across the region.

Please plan ahead and expect longer travel times or consider staying local. You can find real-time travel information on the WSDOT mobile app, the WSDOT Travel Center Map or by signing up for WSDOT's email updates.

How are we keeping traffic moving?

We will apply lessons learned from previous closures to help keep traffic moving as much as possible. That includes a significant temporary change to traffic during the two weekend closures of I-405. We will temporarily reconfigure the northbound I-405 ramps at SR 522 to move as much traffic as possible through the northbound I-405 detour. Drivers should expect changes to the northbound I-405 off-ramp to eastbound and westbound SR 522 during this time as we prioritize traffic traveling north.

The northbound I-405 daytime detour route will be temporarily restriped to include two lanes through the intersection. Drivers should anticipate delays of at least an hour to get through the detour route. 

We will also station uniformed police officers on detour routes to help manage traffic and access to local streets. The southbound I-405 detour will be challenging as many Bothell residents live along the main southbound detour route. We will post signs reminding drivers not to block driveways to help.

Even with these measures, we know this work will be disruptive, but we need to complete this work now to keep the project moving forward. The work itself will be as impressive as it is rare. We rarely remove major highway structures – it’s like our version of the Olympics – and we will share video highlights of this work as it progresses. Once complete, we can continue working at the interchange without major traffic disruptions in the near future.

Change means progress for the I-405/SR 167 corridor

We also know people are still adjusting to the changes made on Nov. 24, 2025. On that date, we added two new intersections with traffic signals on SR 522 and changed how drivers reach Bothell and Woodinville from northbound I-405. These signals were the first step in opening the interchange for expansion.

Some people have asked why we added traffic signals instead of a roundabout, or why we needed to make changes at all.

First, there is not enough space for a roundabout at this location due to the close proximity of the ramps at the interchange including the future direct access ramps to the ETLs. Also, freeway columns block sight lines needed for safe roundabout use. The Sammamish River and a pedestrian trail also limit space.

Second, this project supports a long-term plan for a more connected corridor for drivers, transit users, pedestrians, and cyclists. Thanks to local and regional partner support, this project brings us one step closer to delivering the vision of the I-405 Master Plan in this area.

While traffic signals alone are not an improvement, they are necessary to make larger improvements possible. We also looked for ways to reduce traffic delays. For example, we added a lane to the heavily traveled northbound I-405 ramp towards Woodinville.

We appreciate everyone’s patience while we work to deliver the long-term improvements to this 4.5-mile stretch of I-405. We are on track to deliver these improvements in 2028.