US Bridges

River Road over Big Sulphur Creek

Fair

Sonoma County, California · NE of Cloverdale · Structure no. 20C0251

Built
1988
37 years old
Condition
Fair
inspected July 2023
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
216 ft
2 main spans
Daily traffic
500
2012 count
Owner
County
County Highway Agency

About this bridge

River Road over Big Sulphur Creek is a prestressed concrete continuous box beam or girders - multiple carrying River Road over Big Sulphur Creek in Sonoma County, California. It was built in 1988, so it is 37 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 500 vehicles a day, roughly 6% of them trucks, projected to reach 671 by 2043. The structure is 216 ft (65.7 m) long and 31 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesRiver Road
CrossesBig Sulphur Creek
LocationNE of Cloverdale
RouteCounty Highway 0
CountySonoma County
StateCalifornia
Coordinates38.82309, -123.00343
Functional classRural Minor 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
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20 + Mod
Structure length216 ft (65.7 m)
Longest span107 ft (32.5 m)
Deck width31 ft (9.6 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic500 (2012)
Projected traffic671 by 2043
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 River Road over Big Sulphur Creek built?

It was built in 1988, making it 37 years old in 2025.

What condition is River Road over Big Sulphur 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 July 2023.

How much traffic does River Road over Big Sulphur Creek carry?

About 500 vehicles per day (2012 count), of which roughly 6% are trucks.

How long is River Road over Big Sulphur Creek?

The structure is 216 ft (65.7 m) long with a longest span of 107 ft (32.5 m) and a deck 31 ft wide.

Who owns River Road over Big Sulphur Creek?

It is owned by the County Highway Agency.