• Project

I-405/Brickyard to SR 527 Improvement Project

Project overview

The I-405/Brickyard to SR 527 Improvement Project lies primarily in Bothell on Interstate 405 (I-405), starting 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 work to enhance four and a half miles of the corridor in the area, focusing on improving transportation mobility and reliability throughout the region.

Improvements will include increased express toll lane (ETL) capacity and direct access to state highways. This includes building one new express toll lane in each direction between south of SR 522 and SR 527 (extending the existing dual express toll lane system), widening I-405 through the SR 522 interchange, and building direct access ramps to the express toll lanes at SR 522, and a partial direct access interchange at SR 527 to and from the south connecting to the Canyon Park Park and Ride.

We will also improve connections to regional transit service at both the UW Bothell Station (SR 522) and the park and ride at Canyon Park (SR 527) and add a new transit-only Bus Rapid Transit (BRT) station to connect to Sound Transit’s BRT service along the I-405 corridor, improving connections to the existing park and ride.

The project will include additional local roadway improvements, fish barrier corrections, noise walls, and 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
Legislature allocated $605 million
Project hotline

What to expect

Early construction is happening in the fall of 2023 and will continue through winter 2024. Early work includes field surveys, potholing and geotechnical borings, and vegetation and tree removal. Trees and vegetation at the interchange and hillside area between Woodcrest Estates and I-405 will be removed to clear the space for construction activities. 

Other early work includes speed limit reductions on SR 522, trail messaging, and adding signs on the Sammamish River Trail. Full construction activities are expected to begin in the spring of 2024.

Upcoming I-405 ramp and lane closures

Highway lane closures: 

  • Monday, Feb. 26 to Friday, March 1: Right general-purpose lane and shoulder of northbound I-405 from milepost 23.5 to milepost 21.43 will be closed nightly from 10:00 p.m. – 5:00 a.m.  

  • Monday, Feb. 26 to Thursday, Feb. 29: Right general-purpose lane and shoulder of southbound I-405 from milepost 21.43 to milepost 24.5 will be closed nightly from 8:00 p.m. – 5:00 a.m.  

  • Wednesday, Feb. 28 to Friday, March 1: Right general-purpose lane and shoulder of southbound I-405 from milepost 23.47 to milepost 27.06 will be closed nightly from 10:30 p.m. – 4:00 a.m. 

  • Thursday, Feb. 29 to Friday, March 1: Up to two lanes of eastbound SR 522 from milepost 11 to milepost 11.4 will be closed nightly from 10:00 p.m. – 4:00 a.m. 

  • Thursday, Feb. 29 to Friday, March 1: Left general-purpose lane of eastbound and westbound SR 522 from milepost 11 to milepost 11.4 will be closed nightly from 8:00 p.m. – 4:00 a.m.  

 

Highway ramp closures: 

  • Monday, Feb. 26 to Friday, March 1: The eastbound SR 522 on-ramp to southbound I-405 will be closed nightly from 10:00 p.m. – 5:00 a.m.  

  • Thursday, Feb. 29 to Friday, March 1: The eastbound SR 522 on-ramp to northbound I-405 will be closed nightly from 10:00 p.m. – 4:00 a.m.  

  • Thursday, Feb. 29 to Friday, March 1: The southbound I-405 off-ramp to eastbound SR 522 will be closed nightly from 10:00 p.m. – 4:00 a.m. 

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