Structure 2999F0000000 · King County, WA

SR 203 over Slough

Carries SR 203 over Slough, 1.3 N Jct SR 202.

Overall conditionFair

Set by its lowest-rated component: Superstructure and Substructure at 6 of 9.

How ratings work
Deck7/9 · Good
Superstructuresets the rating6/9 · Satisfactory
Substructuresets the rating6/9 · Satisfactory
Channelnot part of overall8/9 · Very Good
0 failed4 poor6 fair9 excellent

Elevation

Side view, colored by inspection rating
CAR · 15 FT69 FT OVERALL25 FT0ELEVATION · LENGTHS TO SCALE
Deck 7/9Superstructure 6/9 · sets the ratingSubstructure 6/9 · sets the rating

69 ft end to end, longest span 18 ft. Lengths and the car on the deck are drawn to the same scale. Each part is colored by its latest inspection rating. The inventory records lengths but not heights or the layout of the shorter spans, so those are drawn as typical for a multi-beam bridge.

Built194581 years old
Length68.9 ft21 m
Daily traffic7,813counted 2023
Last inspectedMay 2024every 24 months

Location

StateWashington
CountyKing
Location1.3 N Jct SR 202
CarriesSR 203
CrossesSlough
Coordinates47.58446, -121.89944

Physical Characteristics

MaterialWood or Timber
DesignStringer/Multi-beam
Total Length68.9 ft (21 m)
Max Span18.0 ft (5.5 m)
Deck Width39.0 ft (11.9 m)
Deck Area249.9 sq m
Main Spans4
Year Built1945

Traffic

Avg Daily Traffic7,813 (2023)
Truck Traffic10%
Lanes On Bridge2

Inspection & Ownership

Last InspectionMay 2024
Inspection FrequencyEvery 24 months
OwnerState Highway Agency
Historical SignificanceBridge is not eligible for the National Register
Scour Critical8 — Stable, low risk
Structure Number0002999F0000000

How Bridge Ratings Work

Inspectors rate each major part of a bridge (the deck you drive on, the superstructure of beams that holds it up, and the substructure of piers and abutments beneath) on a 0–9 scale. A bridge's overall condition is its lowest of those ratings, so one deteriorated component makes the whole bridge "poor."

0Failed
1Imminent failure
2Critical
3Serious
4Poor
5Fair
6Satisfactory
7Good
8Very good
9Excellent
Good · lowest component 7–9
Fair · lowest component 5–6
Poor · lowest component 0–4

A poor rating is not a closure. It means the bridge is flagged for priority repair or replacement; bridges judged unsafe are closed or posted with weight limits. The waterway (channel) rating is reported, but it does not count toward the overall classification.

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