Project noise alert: Pile driving will begin in mid-November and continue through spring of 2026 in preparation for bridge construction. Construction crews will be driving 48 piles along SR 9 just south of the Snohomish River to a depth of approximately 40-85 feet each. Pile driving work will be limited to daytime hours, 7 a.m. to 6 p.m. Monday - Friday, and may cause noise disturbances for people close to the work zone. If you have concerns about noise from pile driving, please call our toll-free noise hotline at 1-888-808-4DOT (4368).
Project overview
This project will widen State Route 9 between Marsh Road and 2nd Street near the city of Snohomish, build southbound bridges directly to the west of the existing bridges—which will become northbound lanes—over the Snohomish River, and rebuild the on-ramp from 2nd Street to southbound SR 9. It also includes repainting the existing bridge.
What to expect
Pre-construction work is projected to start as early as mid-November 2025. Crews will begin driving piles that will underpin the foundations for the new southbound bridge for SR 9. Pile driving will cause considerable, unavoidable noise near the work zone. Construction on the widening of SR 9 is expected to begin in Spring 2026. This project may require the following closures at various points during construction:
- Nightly full or one-directional closures of ramps and mainline SR 9
- Short (up to 2-weeks) and/or long term (up to 6-months) closures of Lowell Rd
- Partial closures of Marsh Rd and Airport Way
WSDOT will widen SR 9 to two lanes in each direction between Marsh Road and 2nd Street in Snohomish, build new bridges to carry southbound traffic, modify 2nd Street on- and off-ramps to connect with the wider highway, and paint the existing bridge.
The population of Snohomish County increased by over 400,000 residents between 1980 and 2018, adding traffic volumes on most state highways and interstates throughout the region. SR 9 was once a rural highway with free-flow traffic. Now the two-lane road serves as the only north-south alternative to I-5 through Snohomish County for commercial vehicle and commuter traffic, with growing congestion during peak travel times.
WSDOT created a plan to tackle SR 9 congestion through phased improvements that address the worst congestion first. This phase will reduce backups on SR 9 for Snohomish County commuters and residents and improve access to the city of Snohomish.