The Washington Department of Transportation selected Aecon Pacific Northwest, Inc. as they presented the proposal with the best value to conduct both design and build work on the project.

Construction is set to begin later this year with work ending in 2025.

The project will include a diverging diamond interchange, aimed at improving traffic flow by cutting down on the number of signals and opening up more free turns for drivers coming on and off the interstate.

The state’s first diverging diamond interchange opened in August 2020 at Interstate 5 and State Route 510 in Lacey. There’s more than 100 such interchanges in the US, according to WSDOT.

The project will also include widening of around 2 miles of SR 18, construction of a four-lane bridge over Deep Creek and a new two-lane southbound bridge over Raging River. Additionally, there’ll be a dedicated right turn lane from southbound Snoqualmie Parkway to westbound I-90.

The project is funded by existing tax funds and the 2015 Connecting Washington transportation fund, a $16 billion investment in statewide transportation systems and critical infrastructure.

“Aecon has built large highway, civil and private projects across the U.S. and Canada,” WSDOT Project Engineer Mark Allison said. “This is a significant project and one the community has anticipated for a long time. We look forward to working with Aecon to build an interchange that will serve people for many years to come.”