Construction is scheduled for February 2025 to December 2026.
Construction of both northbound and southbound I-5 will begin in early 2025. Lane reductions will begin in February and will last 11 months. During this time, traffic will be shifted onto a temporary two-lane bypass roadway for nine months while excavation and culvert installation occur. Northbound and southbound I-5 construction is anticipated to be complete in early 2026.
Old Highway 99 will be closed for six months in 2026 to construct the final fish-passable structure. During this time, freight and local traffic will detour to I-5.
Key milestones
- February 2025
Construction on I-5 NB and SB begins. Traffic will be reduced to two lanes. - May 2025
I-5 NB and SB traffic will be shifted to a temporary two-lane bypass roadway on I-5. - January 2026
I-5 NB and SB will be returned to existing three-lane configuration.
Old Highway 99 closure begins. - December 2026
Project will be complete.
Project funding
This $57.5 million project is funded by the Move Ahead Washington transportation funding package.