US Bridges

Swanson Road over Yankee Slough

Fair

Sutter County, California · 1.9 MI Ne/O SR 70 · Structure no. 18C0052

Built
1934
91 years old
Condition
Fair
inspected February 2025
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
58 ft
3 main spans
Daily traffic
963
2015 count
Owner
County
County Highway Agency

About this bridge

Swanson Road over Yankee Slough is a steel continuous stringer/multi-beam or girder carrying Swanson Road over Yankee Slough in Sutter County, California. It was built in 1934, so it is 91 years old, older than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in fair condition with a lowest component rating of 5 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 963 vehicles a day, roughly 5% of them trucks, projected to reach 1,362 by 2047. The structure is 58 ft (17.7 m) long and 26 ft wide. If it were closed, the detour would be 6.8 mi (11 km).

CarriesSwanson Road
CrossesYankee Slough
Location1.9 MI Ne/O SR 70
RouteCounty Highway 0
Coordinates38.9676, -121.51545
Functional classRural Major Collector

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating36.4 US tons
Inventory rating21.8 US tons

Structure

MaterialSteel Continuous
DeckCorrugated steel
Main spans3
Design loadUnknown
Structure length58 ft (17.7 m)
Longest span19 ft (5.8 m)
Deck width26 ft (8 m)
Roadway width25 ft (7.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic963 (2015)
Projected traffic1,362 by 2047
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed6.8 mi (11 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerCounty Highway Agency
Maintained byCounty Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Swanson Road over Yankee Slough built?

It was built in 1934, making it 91 years old in 2025.

What condition is Swanson Road over Yankee 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 February 2025.

How much traffic does Swanson Road over Yankee Slough carry?

About 963 vehicles per day (2015 count), of which roughly 5% are trucks.

How long is Swanson Road over Yankee Slough?

The structure is 58 ft (17.7 m) long with a longest span of 19 ft (5.8 m) and a deck 26 ft wide.

Who owns Swanson Road over Yankee Slough?

It is owned by the County Highway Agency.