• Project

I-405/Brickyard to SR 527 Improvement Project

Join us for a quarterly update meeting on Wednesday, February 26 from 1-2 p.m. to share progress updates and answer your questions. Register to attend the webinar at this link.  
If you want to attend this meeting without registering, we will add a join link to this project webpage 30 minutes before the meeting starts. 

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.

Timeline
The project is expected to complete construction in 2028 in alignment with Sound Transit Bus Rapid Transit.
Project status
Construction
Funding
$834 Million
Project hotline

What to expect

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


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.  

Upcoming work

Highway lane closures:

  • The right general-purpose lane of southbound I-405 from milepost 21 to milepost 24.45 will be closed nightly from 11:59 p.m. Monday, Feb. 24 to 5 a.m. Friday, Feb. 28
  • The left general-purpose lane of eastbound SR 522 from milepost 9.5 to milepost 11.65 will be closed overnight from 8 p.m. Monday, Feb. 24 to 4:30 a.m. Tuesday, Feb. 25.
  • The right general-purpose lane of northbound I-405 from milepost 24.2 to milepost 27.06 will be closed nightly from 11 p.m. Monday, Feb. 24 to 5 a.m. Friday, Feb. 28.
  • The right general-purpose lane of southbound SR 527 from milepost 3.2 to milepost 2.95 will be closed nightly from 9 p.m. Wednesday, Feb. 26 to 4 a.m. Friday, Feb. 28.

Highway ramp closures:

  • The Northeast 160th Street to southbound I-405 on-ramp will be closed overnight from 10 p.m. Monday, Feb. 24 to 4 a.m. Tuesday, Feb. 25.
  • The eastbound SR 522 to southbound I-405 on-ramp will be closed nightly from 11:59 p.m. Monday, Feb. 24 to 5 a.m. Friday, Feb. 28.
  • The northbound I-405 to SR 522 off-ramp will be closed nightly from 11:59 p.m. Monday, Feb. 24 to 5 a.m. Saturday, March 1.
  • The Northeast 160th Street to SR 522 collector distributor ramp will be closed nightly from 11 p.m. Monday, Feb. 24 to 5 a.m. Saturday, March 1.

Map of I-405 showing the area that will be improved, from SR 522 to SR 527, highlighted in orange.