A 30-day closure of Lowell-Snohomish River Road begins 7 a.m. Aug. 17. Both directions of the road will be closed 24 hours a day near the SR 9 work zone. No through traffic will be allowed during the closure. Local access is available to residents and businesses remain open on Lowell-Snohomish River Road.
Project overview
Snohomish County has grown significantly and is experiencing increased traffic along many state highways. State Route 9 was once a rural, two-lane highway. Today, it serves as a key north-south alternative to I-5 for commuters and freight moving through Snohomish County. During peak travel times, travelers regularly experience congestion in the area.
WSDOT has developed a phased improvement plan along the SR 9 corridor that addresses where congestion hits hardest. This project will increase the capacity of SR 9 near the City of Snohomish, by building a new bridge across the Snohomish River, expanding about 2 miles the roadway to four lanes and repainting and rehabilitating the existing Snohomish River Bridge, which was originally built in 1959.
What to expect
This three-year project includes:
- Building a new bridge west of the existing Snohomish River bridge to carry southbound SR 9 traffic.
- Building a new overflow bridge south of the SR 9 Snohomish River bridges.
- Rebuilding the southbound SR 9 on-ramp from Second Street.
- Adding an exit-only lane on northbound SR 9 to Second Street.
- Widening SR 9 between Marsh Road and Second Street near Snohomish.
- Making ADA improvements at the SR 9 and Marsh Road intersection.
- Restoring and repainting the existing SR 9 Snohomish River Bridge.
In January 2026, construction crews began driving piles that will underpin the foundations for the new southbound bridges for SR 9. Pile driving will cause considerable, unavoidable noise near the work zone. Both directions of traffic are currently shifted to the east side of SR 9 while crews widen the roadway north of the Marsh Road intersection.
Lowell-Snohomish River Road 30-day closure
A 30-day closure of Lowell-Snohomish River Road begins 7 a.m. Aug. 17. Both directions of the road will be closed 24 hours a day near the SR 9 work zone. No through traffic will be allowed during the closure. Local access is available to residents and businesses remain open on Lowell-Snohomish River Road. Drivers in the area should expect delays and follow the signed detour or use alternate routes.
Detour route
Eastbound traffic should detour via South Second Avenue/Lowell-Larimer Road, turning at Marsh Road and continuing to Airport Way/Avenue D. Westbound traffic will follow the same detour in the reverse direction.
Future closures
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-Snohomish River Road.
- Partial closures of Marsh Road and Airport Way.
Snohomish County’s population grew by more than 400,000 residents from 1980 to 2018 - and traffic increased proportionately on state highways across the region.
SR 9 was once a rural road with free-flow traffic. Today, the two-lane highway intended for locals has become a north-south alternative to I-5 through Snohomish County for commuters and freight traffic, leading to congestion during peak travel times.