US Bridges

County Road 99W over Dunnigan Creek

Fair

Yolo County, California · 0.1 MI SE of CR #89 · Structure no. 22C0051

Built
1936
89 years old
Condition
Fair
inspected January 2025
Type
Culvert
Concrete Continuous
Length
28 ft
3 main spans
Daily traffic
1,256
2015 count
Owner
County
County Highway Agency

About this bridge

County Road 99W over Dunnigan Creek is a concrete continuous culvert carrying County Road 99W over Dunnigan Creek in Yolo County, California. It was built in 1936, so it is 89 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 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 1,256 vehicles a day, roughly 9% of them trucks, projected to reach 1,512 by 2047. The structure is 28 ft (8.5 m) long and 35 ft wide. If it were closed, the detour would be 0.6 mi (1 km).

Location

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CarriesCounty Road 99W
CrossesDunnigan Creek
Location0.1 MI SE of CR #89
RouteCounty Highway 0
CountyYolo County
StateCalifornia
Coordinates38.88676, -121.97114
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
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
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 alignment6: Equal to present minimum criteria
Operating rating44.6 US tons
Inventory rating26.8 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans3
Design loadUnknown
Structure length28 ft (8.5 m)
Longest span9 ft (2.7 m)
Deck width35 ft (10.8 m)
Roadway width34 ft (10.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,256 (2015)
Projected traffic1,512 by 2047
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed0.6 mi (1 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 County Road 99W over Dunnigan Creek built?

It was built in 1936, making it 89 years old in 2025.

What condition is County Road 99W over Dunnigan Creek 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 January 2025.

How much traffic does County Road 99W over Dunnigan Creek carry?

About 1,256 vehicles per day (2015 count), of which roughly 9% are trucks.

How long is County Road 99W over Dunnigan Creek?

The structure is 28 ft (8.5 m) long with a longest span of 9 ft (2.7 m) and a deck 35 ft wide.

Who owns County Road 99W over Dunnigan Creek?

It is owned by the County Highway Agency.