US Bridges

State Park Road over South Fork Eel River

Poor

Humboldt County, California · Benbow State Park · Structure no. 04P0008

Built
1969
56 years old
Condition
Poor
inspected July 2023
Type
Slab
Concrete Continuous
Length
324 ft
14 main spans
Daily traffic
1,100
1998 count
Owner
State
State Park, Forest, or Reservation Agency

About this bridge

State Park Road over South Fork Eel River is a concrete continuous slab carrying State Park Road over South Fork Eel River in Humboldt County, California. It was built in 1969, so it is 56 years old, older than the California average of 54.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 1,100 vehicles a day, roughly 5% of them trucks, projected to reach 1,287 by 2045. The structure is 324 ft (98.8 m) long and 16 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

CarriesState Park Road
CrossesSouth Fork Eel River
LocationBenbow State Park
RouteState Lands Road 0
Coordinates40.05749, -123.78713
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

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.
Substructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating68.9 US tons
Inventory rating41.4 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans14
Design loadHS 20
Structure length324 ft (98.8 m)
Longest span24 ft (7.3 m)
Deck width16 ft (4.9 m)
Roadway width12 ft (3.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,100 (1998)
Projected traffic1,287 by 2045
Trucks5%
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Park, Forest, or Reservation Agency
Maintained byState Park, Forest, or Reservation Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.9 million (2024 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was State Park Road over South Fork Eel River built?

It was built in 1969, making it 56 years old in 2025.

What condition is State Park Road over South Fork Eel River in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in July 2023.

How much traffic does State Park Road over South Fork Eel River carry?

About 1,100 vehicles per day (1998 count), of which roughly 5% are trucks.

How long is State Park Road over South Fork Eel River?

The structure is 324 ft (98.8 m) long with a longest span of 24 ft (7.3 m) and a deck 16 ft wide.

Who owns State Park Road over South Fork Eel River?

It is owned by the State Park, Forest, or Reservation Agency.