US Bridges

Calistoga RD over Mark West Creek

Fair

Sonoma County, California · 4.2 MI N Intersectn SR 12 · Structure no. 20C0122

Built
1967
58 years old
Condition
Fair
inspected October 2024
Type
Slab
Concrete Continuous
Length
147 ft
4 main spans
Daily traffic
5,800
2015 count
Owner
County
County Highway Agency

About this bridge

Calistoga RD over Mark West Creek is a concrete continuous slab carrying Calistoga RD over Mark West Creek in Sonoma County, California. It was built in 1967, so it is 58 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.

It carries about 5,800 vehicles a day, roughly 5% of them trucks, projected to reach 4,907 by 2042. The structure is 147 ft (44.7 m) long and 41 ft wide. If it were closed, the detour would be 11.2 mi (18 km).

Location

Open in Google Maps
CarriesCalistoga RD
CrossesMark West Creek
Location4.2 MI N Intersectn SR 12
RouteCounty Highway 0
CountySonoma County
StateCalifornia
Coordinates38.51557, -122.65486
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
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating83.9 US tons
Inventory rating50.4 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length147 ft (44.7 m)
Longest span41 ft (12.5 m)
Deck width41 ft (12.4 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,800 (2015)
Projected traffic4,907 by 2042
Trucks5%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.2 mi (18 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 Calistoga RD over Mark West Creek built?

It was built in 1967, making it 58 years old in 2025.

What condition is Calistoga RD over Mark West 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 2024.

How much traffic does Calistoga RD over Mark West Creek carry?

About 5,800 vehicles per day (2015 count), of which roughly 5% are trucks.

How long is Calistoga RD over Mark West Creek?

The structure is 147 ft (44.7 m) long with a longest span of 41 ft (12.5 m) and a deck 41 ft wide.

Who owns Calistoga RD over Mark West Creek?

It is owned by the County Highway Agency.