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, correct multiple fish barrier corrections, add noise walls and add new stormwater facilities.

What to expect

Spring 2024, we broke ground on this project and kicked off construction. Watch video highlights from the event. 

SR 522 reduced to one lane in each direction overnight April 18 for traffic shift   

Crews will reduce State Route 522 to a single lane in each direction at Interstate 405 starting at 11:59 p.m., Friday, April 18 to 6 a.m. Saturday, April 19. Crews also will close the westbound SR 522 ramp to northbound I-405 and a signed detour will be in place. These lane and ramp closures will allow crews to shift eastbound and westbound SR 522 traffic north so progress can continue at the interchange. Read more about it on the WSDOT blog.  Drivers should slow down as they approach the work zone and watch for changing traffic control as crews shift eastbound and westbound traffic to the newly paved section of SR 522 further north. Drivers should expect additional traffic on SR 522 in both directions through Bothell during the closures and plan for delays.  

Northbound I-405 closure details, April 23-24  

Overnight lane reductions on northbound I-405 between Northeast 195th Street and State Route 527 will start as early as 11 p.m. Wednesday, April 23 through 5 a.m. Thursday, April 24. Rolling slowdowns will occur during these closures, after 11:59 p.m. During a rolling slowdown, crews temporarily stop traffic for up to 15 minutes to create a gap in the traffic flow which will allow short term access to the roadway to remove a sign over I-405 between Northeast 195th Street and SR 527. 

Crews may close the following northbound I-405 ramps during this work:

• Northeast 85th Street on-ramp
• Northeast 132nd Street on-ramp
• Northeast 160th Street on-ramp   
• Off-ramp to SR 527     

Detours will be in place during the ramp closures to direct drivers around the active work on northbound I-405. Drivers traveling to SR 527 from northbound I-405 should follow the detour route at Northeast 195th Street to access SR 527.

Drivers should expect additional traffic on northbound I-405 approaching Bothell during overnight work and plan for delays.

Sammamish River Trail Reroute and brief closures

Trail users can expect brief closures of the Sammamish River Trail during peak trail-use hours starting in late February and continuing through the month of March. In order to complete work safely next to the trail and move equipment, crews will need to close it temporarily.

What to expect 

• A short reroute around the active work zone underneath the I-405/SR 522 interchange.
• Brief weekday, daytime closures of the trail no longer than 15 minutes per closure and no more than 45 minutes total per day.
• Closures will occur primarily between the hours of 7 a.m. and 5 p.m. but may occur outside of this time as well.
• 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. Please take caution when travelling along the trail outside of daytime hours. 

What is happening:
Pile driving is ongoing in the area to build the foundation for the new northbound I-405 bridge to eastbound SR 522. Crews will conduct this work during daytime hours. This work might require the use of an impact hammer. When in use, people nearby can hear loud pings from the impact hammer strikes.