US Bridges

Utopia Road over Black Slough

Fair

Skagit County, Washington · 0.5 E JCT Hoehn Road · Structure no. 081696000000000

Built
1984
41 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Concrete
Length
144 ft
2 main spans
Daily traffic
77
2023 count
Owner
County
County Highway Agency

About this bridge

Utopia Road over Black Slough is a concrete stringer/multi-beam or girder carrying Utopia Road over Black Slough in Skagit County, Washington. It was built in 1984, so it is 41 years old, younger than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 6 out of 9. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

It carries about 77 vehicles a day, roughly 23% of them trucks, projected to reach 94 by 2043. The structure is 144 ft (43.9 m) long and 29 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

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CarriesUtopia Road
CrossesBlack Slough
Location0.5 E JCT Hoehn Road
RouteCounty Highway 91440
CountySkagit County
StateWashington
Coordinates48.51553, -122.13028
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating68.2 US tons
Inventory rating40.7 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length144 ft (43.9 m)
Longest span71 ft (21.5 m)
Deck width29 ft (8.8 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic77 (2023)
Projected traffic94 by 2043
Trucks23%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedDeck rehabilitation with only incidental widening
Estimated improvement cost$1.6 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Utopia Road over Black Slough built?

It was built in 1984, making it 41 years old in 2025.

What condition is Utopia Road over Black Slough in?

The National Bridge Inventory rates it in fair condition. The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound. The last reported inspection was in July 2023.

How much traffic does Utopia Road over Black Slough carry?

About 77 vehicles per day (2023 count), of which roughly 23% are trucks.

How long is Utopia Road over Black Slough?

The structure is 144 ft (43.9 m) long with a longest span of 71 ft (21.5 m) and a deck 29 ft wide.

Who owns Utopia Road over Black Slough?

It is owned by the County Highway Agency.