US Bridges

State Route 1 over Dunn Creek

Fair

Mendocino County, California · 01-MEN-001-92.83 · Structure no. 10 0304

Built
2014
11 years old
Condition
Fair
inspected September 2023
Type
Slab
Concrete Continuous
Length
135 ft
3 main spans
Daily traffic
810
2009 count
Owner
State
State Highway Agency

About this bridge

State Route 1 over Dunn Creek is a concrete continuous slab carrying State Route 1 over Dunn Creek in Mendocino County, California. It was built in 2014, so it is 11 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 810 vehicles a day, roughly 15% of them trucks, projected to reach 1,020 by 2043. The structure is 135 ft (41.3 m) long and 47 ft wide. If it were closed, the detour would be 44.7 mi (72 km).

Location

Open in Google Maps
CarriesState Route 1
CrossesDunn Creek
Location01-MEN-001-92.83
RouteState Highway 1
CountyMendocino County
StateCalifornia
Coordinates39.79837, -123.82047
Functional classRural Minor Arterial

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.
Substructure7 GoodSome minor problems.
Channel and channel protection9 ExcellentNo problems noted.
Last inspectionSeptember 2023
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 geometry9: Superior to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating46.4 US tons
Inventory rating35.7 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length135 ft (41.3 m)
Longest span44 ft (13.4 m)
Deck width47 ft (14.3 m)
Roadway width44 ft (13.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic810 (2009)
Projected traffic1,020 by 2043
Trucks15%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed44.7 mi (72 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 State Route 1 over Dunn Creek built?

It was built in 2014, making it 11 years old in 2025.

What condition is State Route 1 over Dunn 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 September 2023.

How much traffic does State Route 1 over Dunn Creek carry?

About 810 vehicles per day (2009 count), of which roughly 15% are trucks.

How long is State Route 1 over Dunn Creek?

The structure is 135 ft (41.3 m) long with a longest span of 44 ft (13.4 m) and a deck 47 ft wide.

Who owns State Route 1 over Dunn Creek?

It is owned by the State Highway Agency.