US Bridges

Willow Creek Road over Willow Creek

Fair

Sonoma County, California · 2.4 MI E/O RTE 1 · Structure no. 20C0388

Built
1975
50 years old
Condition
Fair
inspected March 2022
Type
Stringer/Multi-beam or Girder
Steel
Length
61 ft
1 main span
Daily traffic
120
2012 count
Owner
County
County Highway Agency

About this bridge

Willow Creek Road over Willow Creek is a steel stringer/multi-beam or girder carrying Willow Creek Road over Willow Creek in Sonoma County, California. It was built in 1975, so it is 50 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 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 120 vehicles a day, projected to reach 194 by 2040. The structure is 61 ft (18.6 m) long and 28 ft wide. If it were closed, the detour would be 29.8 mi (48 km).

Location

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CarriesWillow Creek Road
CrossesWillow Creek
Location2.4 MI E/O RTE 1
RouteCounty Highway 0
CountySonoma County
StateCalifornia
Coordinates38.43093, -123.06961
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 protection7 GoodSome minor problems.
Last inspectionMarch 2022
Inspection intervalevery 48 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 adequacy4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment4: Meets minimum tolerable limits to be left in place as is
Operating rating67.1 US tons
Inventory rating40.3 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans1
Design loadUnknown
Structure length61 ft (18.6 m)
Longest span59 ft (18 m)
Deck width28 ft (8.6 m)
Roadway width28 ft (8.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic120 (2012)
Projected traffic194 by 2040
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.8 mi (48 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 Willow Creek Road over Willow Creek built?

It was built in 1975, making it 50 years old in 2025.

What condition is Willow Creek Road over Willow 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 March 2022.

How much traffic does Willow Creek Road over Willow Creek carry?

About 120 vehicles per day (2012 count).

How long is Willow Creek Road over Willow Creek?

The structure is 61 ft (18.6 m) long with a longest span of 59 ft (18 m) and a deck 28 ft wide.

Who owns Willow Creek Road over Willow Creek?

It is owned by the County Highway Agency.