• Project

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.

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

This spring we broke ground on this project and kicked off construction. Watch video highlights from the event


Traffic switch on westbound SR 522 to northbound I-405 on-ramp

Crews switched traffic over onto the newly constructed bridge deck on top of the first completed portion of the new Par Creek fish passage. This shift opens a new work zone to continue progress constructing the fish passage that will run underneath SR 522 to the Sammamish River.


Sammamish River Trail Reroute and brief closures

Starting as soon as Dec. 16, crews will conduct brief closures and implement a short reroute of the Sammamish River Trail to complete work safely in the area. 

You can expect:

  • A short reroute around the active work zone underneath the I-405/SR 522 interchange. 
  • Brief daytime closures of the trail no longer than 15 minutes and not during peak hours (no closures 5 - 9 a.m. and 3 - 7 p.m.).
  • Overnight closures will not take place during the weekends. Please use caution when travelling along the trail outside of daytime hours. 
  • There will be signage along the trail ahead of the reroute to direct you where to go. Flaggers may be present during active construction for assistance. 

What is happening:
Pile driving is ongoing in the area. The pile driving work supports foundation work for the future northbound I-405 bridge to eastbound SR 522. Crews will pile drive only during daytime hours. The pile driving will move to the north side of the Sammamish River near Northeast Woodinville Drive (view map image for reference). 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 northbound I-405 from milepost 24.2 to milepost 27.06 will be closed overnight from 11 p.m. Tuesday, Jan. 7 to 5 a.m. Wednesday, Jan. 8.
  • The left express toll lane of southbound I-405 from milepost 23.75 to milepost 27.2 will be closed overnight from 8 p.m. Wednesday, Jan. 8 to 4:30 p.m. Thursday, Jan. 9.

Highway ramp closures:

  • The Northeast 160th Street to southbound I-405 on-ramp at milepost 22.6 will be closed overnight from 10 p.m. Tuesday, Jan. 7 to 4 a.m. Wednesday, Jan. 8.

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