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Road Services Division Capital Improvement Program (CIP)

February 1, 2021 - We are in the process of reworking this website. The project information contained here may not be comprehensive or up-to-date. Thank you for your patience, we should have a new site available soon. More project info.

Coal Creek Bridge #3035A Replacement


›› See the public outreach web page. Weight limit restriction on this bridge.

Project No.:  1135997
Project limits:  Lake Walker Road at Coal Creek
Project type:  Bridge
Thomas Bros. Map No.:  799C4

Project description

To replace Coal Creek Bridge #3035A which has been affected by new federal requirements. These requirements have resulted in restrictions on heavy vehicles, which pose safety concerns if not promptly and systematically addressed.

Why is King County doing this project?

Following a bridge collapse, and, more importantly, a recent decision by the Federal Highway Administration (FHWA) to allow heavier trucks on roadways, the FHWA developed new calculations for determining the weight that a bridge can safely carry. All state and local governments are evaluating publicly owned vehicle bridges using these new criteria and determining whether additional vehicle weight restrictions must be placed on bridges. Coal Creek Bridge #509A was built in 1958 with steel girders that are older than the bridge because these girders were reused from another location. The substructure is constructed of timber. The bridge has a sufficiency rating of 9.68 out of 100 and was identified in the King County 2017 Bridge Report as a priority need for replacement, using council-adopted criteria. Due to its age and condition, it is not feasible to repair or rehabilitate the bridge to meet current standards for structural, geotechnical, hydraulic, road design and environmental requirements. The bridge has a traffic volume of approximately 300 vehicles per day, including about five trucks per day and provides access to a Department of Fish and Wildlife boat launch for public recreational access to Lake Walker. It is a designated county snow/ice route.

Project management phase:  Final Design

Status as of July 6, 2020

Final Design started


See also

Environmental compliance for bridge activities External link graphic
King County Annual Bridge Report
Overlegal truck permit
Road closures
Road standards
Roads' future - learn what's needed to preserve our road network
Seattle bridges External link graphic
Title VI information
WSDOT Historic Bridges External link graphic

Adopted Capital Improvement Program & program overview

The Road Services Division Capital Improvement Program (CIP) contains all design and construction and studies for improvements on roads, bridges or transportation facilities in the unincorporated areas of King County.

Vicinity map

Vacinity map