US Bridges

Freestone Flat RD over Salmon Creek

FairPosted for load

Sonoma County, California · 0.2 MI E Bohemian HWY · Structure no. 20C0440

Built
1955
70 years old
Condition
Fair
inspected October 2023
Type
Truss - Deck
Steel
Length
103 ft
1 main span
Daily traffic
121
2015 count
Owner
County
County Highway Agency

About this bridge

Freestone Flat RD over Salmon Creek is a steel truss - deck carrying Freestone Flat RD over Salmon Creek in Sonoma County, California. It was built in 1955, so it is 70 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. Its operating status is: posted for load restriction.

It carries about 121 vehicles a day, roughly 5% of them trucks, projected to reach 153 by 2040. The structure is 103 ft (31.4 m) long and 14 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

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CarriesFreestone Flat RD
CrossesSalmon Creek
Location0.2 MI E Bohemian HWY
RouteCounty Highway 0
CountySonoma County
StateCalifornia
Coordinates38.37898, -122.92327
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
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionOctober 2023
Inspection intervalevery 24 months
Operating statusPosted for load restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating33.2 US tons
Inventory rating22.5 US tons

Structure

Structure typeTruss - Deck
MaterialSteel
DeckOpen grating
Main spans1 (+1 approach)
Design loadUnknown
Structure length103 ft (31.4 m)
Longest span63 ft (19.2 m)
Deck width14 ft (4.2 m)
Roadway width12 ft (3.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic121 (2015)
Projected traffic153 by 2040
Trucks5%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 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 Freestone Flat RD over Salmon Creek built?

It was built in 1955, making it 70 years old in 2025.

What condition is Freestone Flat RD over Salmon 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 October 2023.

How much traffic does Freestone Flat RD over Salmon Creek carry?

About 121 vehicles per day (2015 count), of which roughly 5% are trucks.

How long is Freestone Flat RD over Salmon Creek?

The structure is 103 ft (31.4 m) long with a longest span of 63 ft (19.2 m) and a deck 14 ft wide.

Who owns Freestone Flat RD over Salmon Creek?

It is owned by the County Highway Agency.