US Bridges

Trenton Healdsbrg over Mark West Creek

Fair

Sonoma County, California · 0.3 MI N of River RD · Structure no. 20C0239

Built
1988
37 years old
Condition
Fair
inspected February 2025
Type
Slab
Concrete Continuous
Length
184 ft
4 main spans
Daily traffic
1,700
2018 count
Owner
County
County Highway Agency

About this bridge

Trenton Healdsbrg over Mark West Creek is a concrete continuous slab carrying Trenton Healdsbrg over Mark West 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 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 1,700 vehicles a day, roughly 2% of them trucks, projected to reach 2,166 by 2047. The structure is 184 ft (56 m) long and 33 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesTrenton Healdsbrg
CrossesMark West Creek
Location0.3 MI N of River RD
RouteCounty Highway 0
CountySonoma County
StateCalifornia
Coordinates38.49384, -122.85286
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
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.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionFebruary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
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 adequacy7: Better than present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating59.6 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20 + Mod
Structure length184 ft (56 m)
Longest span50 ft (15.2 m)
Deck width33 ft (10 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,700 (2018)
Projected traffic2,166 by 2047
Trucks2%
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 Trenton Healdsbrg over Mark West Creek built?

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

What condition is Trenton Healdsbrg 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 February 2025.

How much traffic does Trenton Healdsbrg over Mark West Creek carry?

About 1,700 vehicles per day (2018 count), of which roughly 2% are trucks.

How long is Trenton Healdsbrg over Mark West Creek?

The structure is 184 ft (56 m) long with a longest span of 50 ft (15.2 m) and a deck 33 ft wide.

Who owns Trenton Healdsbrg over Mark West Creek?

It is owned by the County Highway Agency.