US Bridges

Sonoma Mtn RD over Hillside

Fair

Sonoma County, California · 1.27 MI S/O Bennett V RD · Structure no. 20C0551

Built
2011
14 years old
Condition
Fair
inspected October 2024
Type
Stringer/Multi-beam or Girder
Steel
Length
30 ft
1 main span
Daily traffic
600
2015 count
Owner
County
County Highway Agency

About this bridge

Sonoma Mtn RD over Hillside is a steel stringer/multi-beam or girder carrying Sonoma Mtn RD over Hillside in Sonoma County, California. It was built in 2011, so it is 14 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 600 vehicles a day, roughly 1% of them trucks, projected to reach 714 by 2042. The structure is 30 ft (9 m) long and 9 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesSonoma Mtn RD
CrossesHillside
Location1.27 MI S/O Bennett V RD
RouteCounty Highway 0
CountySonoma County
StateCalifornia
Coordinates38.38083, -122.62898
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating81 US tons
Inventory rating48.6 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckCorrugated steel
Main spans1
Design loadHS 20 + Mod
Structure length30 ft (9 m)
Longest span29 ft (8.9 m)
Deck width9 ft (2.7 m)
Roadway width22 ft (6.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic600 (2015)
Projected traffic714 by 2042
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesOther
Detour if closed14.9 mi (24 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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was Sonoma Mtn RD over Hillside built?

It was built in 2011, making it 14 years old in 2025.

What condition is Sonoma Mtn RD over Hillside 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 2024.

How much traffic does Sonoma Mtn RD over Hillside carry?

About 600 vehicles per day (2015 count), of which roughly 1% are trucks.

How long is Sonoma Mtn RD over Hillside?

The structure is 30 ft (9 m) long with a longest span of 29 ft (8.9 m) and a deck 9 ft wide.

Who owns Sonoma Mtn RD over Hillside?

It is owned by the County Highway Agency.