US Bridges

Fort Ross Rd. over Hillside

Fair

Sonoma County, California · 0.65MI W of King Ridge RD · Structure no. 20C0521

Built
1999
26 years old
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
155 ft
8 main spans
Daily traffic
200
2015 count
Owner
County
County Highway Agency

About this bridge

Fort Ross Rd. over Hillside is a steel stringer/multi-beam or girder carrying Fort Ross Rd. over Hillside in Sonoma County, California. It was built in 1999, so it is 26 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 200 vehicles a day, roughly 5% of them trucks, projected to reach 209 by 2040. The structure is 155 ft (47.2 m) long and 7 ft wide. If it were closed, the detour would be 44.7 mi (72 km).

Location

Open in Google Maps
CarriesFort Ross Rd.
CrossesHillside
Location0.65MI W of King Ridge RD
RouteCounty Highway 0
CountySonoma County
StateCalifornia
Coordinates38.54085, -123.10015
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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment8: Equal to present desirable criteria
Operating rating80.4 US tons
Inventory rating48.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckCorrugated steel
Main spans8
Design loadUnknown
Structure length155 ft (47.2 m)
Longest span19 ft (5.9 m)
Deck width7 ft (2.2 m)
Roadway width19 ft (5.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic200 (2015)
Projected traffic209 by 2040
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesOther
Detour if closed44.7 mi (72 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 Fort Ross Rd. over Hillside built?

It was built in 1999, making it 26 years old in 2025.

What condition is Fort Ross 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 June 2023.

How much traffic does Fort Ross Rd. over Hillside carry?

About 200 vehicles per day (2015 count), of which roughly 5% are trucks.

How long is Fort Ross Rd. over Hillside?

The structure is 155 ft (47.2 m) long with a longest span of 19 ft (5.9 m) and a deck 7 ft wide.

Who owns Fort Ross Rd. over Hillside?

It is owned by the County Highway Agency.