US Bridges

Old 40 Mile RD over West Best Slough

Fair

Yuba County, California · 0.3 MI E of 40 MI RD · Structure no. 16C0042

Built
1927
98 years old
Condition
Fair
inspected August 2024
Type
Tee Beam
Concrete Continuous
Length
54 ft
2 main spans
Daily traffic
50
2011 count
Owner
County
County Highway Agency

About this bridge

Old 40 Mile RD over West Best Slough is a concrete continuous tee beam carrying Old 40 Mile RD over West Best Slough in Yuba County, California. It was built in 1927, so it is 98 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 50 vehicles a day, roughly 1% of them trucks, projected to reach 111 by 2046. The structure is 54 ft (16.5 m) long and 22 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesOld 40 Mile RD
CrossesWest Best Slough
Location0.3 MI E of 40 MI RD
RouteCounty Highway 0
CountyYuba County
StateCalifornia
Coordinates39.02702, -121.50785
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure8 Very GoodNo problems noted.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection4 PoorAdvanced section loss, deterioration, spalling or scour.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating28.9 US tons
Inventory rating20 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadUnknown
Structure length54 ft (16.5 m)
Longest span27 ft (8.1 m)
Deck width22 ft (6.8 m)
Roadway width20 ft (6.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2011)
Projected traffic111 by 2046
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 Old 40 Mile RD over West Best Slough built?

It was built in 1927, making it 98 years old in 2025.

What condition is Old 40 Mile RD over West Best 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 August 2024.

How much traffic does Old 40 Mile RD over West Best Slough carry?

About 50 vehicles per day (2011 count), of which roughly 1% are trucks.

How long is Old 40 Mile RD over West Best Slough?

The structure is 54 ft (16.5 m) long with a longest span of 27 ft (8.1 m) and a deck 22 ft wide.

Who owns Old 40 Mile RD over West Best Slough?

It is owned by the County Highway Agency.