• 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
Pre-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. Construction at the I-405/SR 522 interchange continues to progress as crews prepare to begin work on the new bridge that will connect northbound I-405 to eastbound SR 522. Construction of the new bridge will allow us to widen the SR 522 interchange to accommodate the dual toll express lane system on 4.5 miles of the corridor. 


Notification of pile driving at the SR 522 interchange  

As soon as July 22, 2024, the design-builder Skanska will perform pile driving work to construct a temporary pile wall that will support access to foundation work for the new northbound I-405 bridge to eastbound SR 522. Crews plan to complete this work during daytime hours for approximately two weeks. The pile driving will take place on the south side of the Sammamish River near Northeast Woodinville Drive.

During this work, design-builder Skanska will minimize noise by using a vibratory hammer to install the piles and reserve the impact hammer only when absolutely necessary. When an impact hammer is used typically pings can be heard on each strike. Factors such as soil conditions, depth and location may dictate the difference. 

 During the pile driving work, you can expect to experience the following nearby the work area: 

  • Loud noises  
  • Noise from trucks and machinery that support the work including staging, loading, moving equipment and material and backup beeps. 
  • Possible noise associated with the impact hammer (pings from each strike) when in use. 
  • Vibration, especially associated with the vibratory hammer.  
  • Short term closures to nearby roadways and the Sammamish River Trail 

Sammamish River Trail Reroute 

The Sammamish River Trail is scheduled for reroute in mid-August as contractor crews work on constructing a new shoring wall and remove the existing wall along the trail. In preparation for this work, the trail will have potential night closures from 10 p.m. to 5 a.m. that will take place beginning as soon as August 2024. If you travel along the trail, here is what to expect: 

  • A short reroute around the shoring wall underneath the I-405/SR 522 interchange
  • Potential nighttime closures as soon as August 2024, so please take caution when traveling along the trail outside of daytime hours
  • Reroute will be made with temporary asphalt while crews work along the actual trail
  • Signage and traffic control along the trail ahead of the reroute to direct you where to go

Upcoming I-405 ramp and lane closures

Highway lane closures:

  • Thursday, July 25 to Friday, July 26: The northbound I-405 off-ramp to eastbound SR 527 from milepost 26.45 to milepost 26.75 will be closed nightly from 12 a.m. – 5 a.m.
  • Wednesday, July 24 to Thursday, July 25: The right two general-purpose lanes of southbound I-405 from milepost 27.75 to milepost 26.2 will be closed nightly from 11 p.m. – 4 a.m.
  • Tuesday, July 23 to Wednesday, July 24 and Thursday, July 25 to Friday, July 26: The right general-purpose lane of southbound I-405 from milepost 24.2 to milepost 29 will be closed nightly from 10:30 p.m. – 4 a.m.
  • Monday, July 22 to Tuesday, July 23: The right general-purpose lane and shoulder of northbound I-405 from milepost 24.2 to milepost 27.06 will be closed nightly from 11 p.m. – 5 a.m.

Highway ramp closures:

  • Wednesday, July 24 to Thursday, July 25: The southbound I-405 off-ramp to SR 527 from milepost 27.75 to milepost 26.28 will be closed nightly from 11 p.m. – 4 a.m.
  • Wednesday, July 24 to Thursday, July 25: The southbound SR 527 to southbound I-405 on-ramp from milepost 27.75 to milepost 26.28 will be closed nightly from 11 p.m. – 4 a.m.
  • Wednesday, July 24 to Thursday, July 25: The northbound SR 527 to southbound I-405 on-ramp from milepost 27.75 to milepost 26.28 will be closed nightly from 11 p.m. – 4 a.m.

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