US Bridges

County Road 27 over Willow Slough

Fair

Yolo County, California · 1.5 MI W of CO RD 98 · Structure no. 22C0088

Built
1987
38 years old
Condition
Fair
inspected November 2023
Type
Slab
Concrete Continuous
Length
144 ft
4 main spans
Daily traffic
1,476
2009 count
Owner
County
County Highway Agency

About this bridge

County Road 27 over Willow Slough is a concrete continuous slab carrying County Road 27 over Willow Slough in Yolo County, California. It was built in 1987, so it is 38 years old, younger 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 1,476 vehicles a day, roughly 5% of them trucks, projected to reach 893 by 2043. The structure is 144 ft (43.9 m) long and 33 ft wide. If it were closed, the detour would be 8.1 mi (13 km).

Location

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CarriesCounty Road 27
CrossesWillow Slough
Location1.5 MI W of CO RD 98
RouteCounty Highway 0
CountyYolo County
StateCalifornia
Coordinates38.61963, -121.83254
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 protection8 Very GoodNo problems noted.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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 adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length144 ft (43.9 m)
Longest span36 ft (11 m)
Deck width33 ft (10 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,476 (2009)
Projected traffic893 by 2043
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed8.1 mi (13 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 27 over Willow Slough built?

It was built in 1987, making it 38 years old in 2025.

What condition is County Road 27 over Willow 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 November 2023.

How much traffic does County Road 27 over Willow Slough carry?

About 1,476 vehicles per day (2009 count), of which roughly 5% are trucks.

How long is County Road 27 over Willow Slough?

The structure is 144 ft (43.9 m) long with a longest span of 36 ft (11 m) and a deck 33 ft wide.

Who owns County Road 27 over Willow Slough?

It is owned by the County Highway Agency.