Locust Way - Bridge 504

December 5, 2016 Update

Locust Way Bridge 504 is now open to traffic between 228th Street and Barker Road. Over the next two weeks traffic on the bridge may be restricted to one lane intermittently during the day. Thank you area residents and commuters for your patience during this project! 


Bridge 504 carries Locust Way over Swamp Creek. It is only two lanes and located between Bothell and Brier. Built originally in 1936 and rebuilt in 1958 and 1988, it will be replaced in summer 2016.

To meet current federal bridge standards, Snohomish County is replacing the bridge with a new structure that is longer, wider, and several feet higher. The bridge will be lengthened from 41 to 70 feet and widened from 23 to 47 feet. The new bridge will have two driving lanes, bike lanes, and sidewalks. Railings and guardrails will be installed where needed.

The new bridge foundations will be placed outside of the existing creek channel; crews will also remove the center pier, which currently catches debris that can cause damage to the bridge.

Runoff from the new bridge and portions of the road will enter a new storm water system and discharge to a bioswale, a type of biofilter designed to remove silt and pollution from surface runoff by directing the water through a drainage course filled with vegetation.

Environmental Review

An environmental review of the bridge replacement project was completed in compliance with the State Environmental Policy Act (SEPA). SEPA requires that all state and local agencies identify and evaluate the environmental impacts of their land use decisions. An environmental checklist was prepared July 30, 2012. A Notice of Determination of Nonsignificance (DNS) and Land Disturbing Activity (LDA) Permit have been issued.

These documents are available by viewing the links below or from Snohomish County public works during normal business hours:


Construction is currently underway for this project and is expected to be completed by mid-to-late November 2016.