I-405/Brickyard to SR 527 Improvement Project

Project overview

The I-405/Brickyard to SR 527 Improvement Project enhances four and a half miles of the corridor, primarily in Bothell, from just south of the State Route 522 interchange and ending at the SR 527 interchange. WSDOT, Sound Transit and design-build contractor Skanska USA Inc., will deliver improvements that benefit all users, while addressing aging infrastructure, opening upstream fish habitat, and connecting communities, freight and Regional Growth Centers throughout the corridor.

Since implemented in 2015, express toll lanes (ETL) have helped improve reliability of trips on the north end of the I-405 corridor, however the single-lane section still experiences heavy congestion, especially for people traveling south during the morning commute. The project will extend the dual-express toll lane system on the north end of I-405 and improve access to the voter-approved Stride bus rapid transit service to address congestion and help keep all vehicles moving efficiently.

This project includes three new Stride stations and will build direct access ramps to the ETL system at SR 522, along with a partial direct access interchange at SR 527 to and from the south connecting to the Canyon Park Park & Ride. These enhancements will allow Stride vehicles to travel in the new ETLs between Lynnwood and Bellevue while stopping briefly to pick-up and drop-off passengers without having to leave the highway system. Having dedicated ETL access in the center of the freeway will make travel more efficient supporting the new Stride service with buses arriving every 10 minutes for most of the day.

Additionally, the project will address aging infrastructure, restore stream connections, add noise walls and add new stormwater facilities.

What to expect

Both directions of I-405 in Bothell to close for ramp removal, March 7-9 and March 13-16  

Construction across the greater Puget Sound region continues to intensify as multiple projects move forward at the same time. As part of that sustained work, both directions of Interstate 405 in Bothell will fully close during the first two weekends of March so crews can remove the remaining portion of the previous northbound I-405 to State Route 522 ramp over I-405. 

Closure details

March 7-9: 6 p.m. Saturday, March 7, to 4 a.m. Monday, March 9, crews will close all lanes of northbound I-405 at the SR 522 Interchange and all lanes of southbound I-405 from SR 527 to SR 522 to remove ramp sections over I-405. 

March 13-16: 9 p.m. Friday, March 13, to 4 a.m. Monday, March 16, crews will close all lanes of northbound I-405 at the SR 522 Interchange and all lanes of southbound I-405 from SR 527 to SR 522. 

Ramp closures
Ramp closures are required overnight to restripe the northbound I-405 detour route temporarily to two lanes to increase capacity and again to reset the lanes. Travelers can expect closures of the following ramps overnight:

• The northbound I-405 on-ramp to westbound SR 522.
• The eastbound and westbound SR 522 on-ramps to northbound I-405.

During the southbound I-405 full closures the following ramps will also close:

• SR 527 on-ramps to southbound I-405.
• Northeast 195th Street on- and off-ramps (exit 24) to southbound I-405.
• I-405 off-ramp to SR 522 (Exit 23)

Drivers should pay attention to signage along the roadway and stay in the far-right lane to head east. Anticipate back-ups.

Detour routes

Signed detour routes will be in place:

• Northbound I-405 nighttime detour: In place while crews restripe lanes for daytime detour and reset lanes before reopening to traffic Monday morning.The northbound I-405 off-ramp to SR 522 will remain in a temporary configuration in between the two weekend closures of I-405. This means that only one lane of the ramp will head east to Woodinville from 5 a.m. Friday, March 6 to 4 a.m. Monday morning March 16. 
• Northbound I-405 daytime detour: Westbound SR 522 traffic will make a right turn at the traffic signal instead of using the merge ramp to help prioritize northbound I-405 traffic. 
• Southbound I-405 detour. 
   

Drivers are advised to slow down and pay attention through the detours. Uniformed police officers will help direct traffic.

Effect on traffic

Detour routes are limited and cannot carry normal I-405 freeway volumes. Travelers should expect 2- to 3-mile backups on I-405 during the full closures. A one-hour delay in both directions is the best-case scenario during peak travel times. 

Northbound I-5 through Seattle also is restricted to two lanes for the Revive I-5 work. These restrictions will limit northbound travel options through the Seattle metro area both weekends. The I-5 express lanes are open northbound-only 24 hours a day for people going north of downtown Seattle. There are no northbound express lane exits to downtown.

Over the next two years, travelers across Greater Puget Sound will see an unprecedented level of construction activity. The region's transportation system is at a tipping point. Much of the infrastructure is old, overstressed and operating beyond what it was designed to handle. Meanwhile, the region's population continues to grow and must be managed safely and strategically. That means adding capacity to roads, improving access and strengthening transit connections. More information about WSDOT’s efforts were recently shared on the WSDOT blog: “Why so much construction in Puget Sound? What to know about I-5, I-405, SR 520 and more through 2028.” 

People should plan ahead and prepare for longer travel times, use alternative routes or consider delaying trips. Real-time travel information is available on the WSDOT mobile app, the WSDOT Travel Center Map or by signing up for WSDOT's email updates.

Reminder to slow down to 35 MPH

WSDOT has started a pilot Work Zone Speed Limit Camera program. This program will be coming to the project as early as April 28, with a camera placed first on eastbound SR 522, before the I-405 interchange. The location of the speed camera may be adjusted throughout the project. Please slow down on SR 522 near the I-405 interchange for the safety of constructions crews and the traveling public.

Sammamish River Trail reroute and brief closures

In order to complete work safely next to the Sammamish River Trail and move equipment, crews will need to continue to close it temporarily. Trail users can expect brief closures for the duration of the project which is scheduled to be complete in Spring 2028. 

There will be a short reroute around the active work zone underneath the I-405/SR 522 interchange. Brief weekday, daytime closures of the trail will occur no longer than 15 minutes per closure and no more than 45 minutes total per day. 

• Closures will occur intermittently between the hours of 9 a.m. and 3 p.m., and overnight between 7 p.m. and 5 a.m.
• Signage along the trail ahead of the reroute will direct you where to go. Flaggers will be present during closures to direct traffic. 

Overnight closures will not take place during the weekends, except on select weekends with prior notice. Please take caution when travelling along the trail outside of daytime hours. Construction activities are ongoing in the area to build the foundation for the new northbound I-405 ramp bridge to eastbound SR 522. Crews will conduct this work during daytime hours.  Trail users can expect nighttime closures in mid-June when crews set girders for the new I-405 ramp bridge.