I-90 over Mercer Slough

Fair Condition56 years old22,361 vehicles/day

Location

StateWashington
CountyKing
Location6.4 E Jct I-5
CarriesI-90
CrossesMercer Slough
Coordinates47.57978, -122.18631

Condition Ratings

Overall ConditionFair
Deck6 (Satisfactory)
Superstructure5 (Fair)
Substructure6 (Satisfactory)
Channel/Waterway8 (Very Good)
Scour Critical8 — Stable, low risk

Physical Characteristics

MaterialConcrete Continuous
DesignSlab
Total Length1871.1 ft (570.3 m)
Max Span56.1 ft (17.1 m)
Deck Width36.4 ft (11.1 m)
Deck Area6330.3 sq m
Main Spans44
Year Built1970

Traffic

Avg Daily Traffic22,361 (2023)
Truck Traffic5%
Lanes On Bridge3
Lanes Under Bridge2

Inspection & Ownership

Last Inspection223
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Structure Number0008610D0000000

Nearby Bridges

I-90 over Mercer Slough 0.0 mi Fair I-90 over Mercer Slough 0.1 mi Fair I-90 S-e Ramp over I-90 Mercer Slough 0.1 mi Fair I-90 W-n Ramp over I-90 Wbcd 0.1 mi Fair I-90 over Mercer Sl 0.2 mi Poor I-90 over Mercer Slough 0.2 mi Poor E-e Ramp over I-90 Ramps Mercer Sl 0.3 mi Good I-90 Ramp over Mercer Slough I-90 0.4 mi Good Skagit Key over Coal Creek 0.5 mi Good I-90 Ramp To I-405 over I-90 Mainline 0.5 mi Fair