As part of an $834-million design-build contract awarded to Skanska last month by the Washington State Dept. of Transportation and Sound Transit, a 4.5-mile stretch of Interstate 405 near Bothell, Wash. a Seattle suburb, will gain extended dual express toll lanes.

The I-405 Brickyard to SR 527 Improvement Project will create the lanes in each direction of the freeway to ease strain on its general-purpose lanes east of Interstate 5. This extends the express toll lane count from one lane to two, both northbound and southbound. 

The state DOT awarded the project on July 27 on a best value basis. Skanska's winning bid was $242 million over the agency's estimated $525 million cost. The only other participant, a joint venture of Walsh and Canada-based Aecon, bid $1.84 billion for the project.

During the evaluation of the competitors, technical scores were subtracted from the price proposals to determine the best value. Skanska’s technical score, 54,720,000, was higher than Walsh Aecon’s 30,490,000. But any other factors that could account for the great difference in pricing the design-build work aren’t clear. 

Using toll revenue, the Move Ahead Washington transportation grant program and Sound Transit will fund the project with an expected construction start in late 2023 and completion in 2028. 

“Our partnership with Sound Transit is crucial for this project,” Lisa Hodgson, state SDOT I-405/SR 167 program administrator, says in a statement. “By creating more connections to regional transit service and aligning with Sound Transit’s plans for bus rapid transit, we’re enhancing convenience and accessibility.” 

Once the I-405 Brickyard to SR 527 Improvement Project is complete, Sound Transit’s Stride bus rapid transit service will use the new lanes and freeway stations, removing buses from the general-purpose traffic lanes. 

The project includes creating direct access ramps to the toll lanes at State Route 522 and a partial direct access interchange at State Route 527, which features connections to the Canyon Park Park-and-Ride and a future rapid transit station at the University of Washington-Bothell campus. A new bridge is also required at the I-405/SR 522 interchange. 

AECOM, a member of the design-build team, will be the lead designer on the project.

The Brickyard to SR 527 Improvement Project is part of the larger I-405/SR 167 Corridor Program, a 150-project master plan designed to improve travel between Lynnwood and the Renton/Tukwila area with more than 50 miles of express toll lanes, regular lanes and high-capacity transit. 

To date, the state DOT has delivered 16 projects valued at $1.5 billion from the master plan with another 10 worth $2 billion in progress. 

The Brickyard to SR 527 Improvement Project and the Renton-to-Bellevue Project are the two largest from the state DOT. with partner agencies and municipalities also involved to deliver projects. The state estimates $4 billion of funded corridor improvements as part of the plan.