US Bridges

Forest Road 600 over Caspar Creek

Fair

Mendocino County, California · South of JCT With RD 620 · Structure no. 10F0030

Built
1972
53 years old
Condition
Fair
inspected May 2023
Type
Arch - Deck
Steel
Length
32 ft
1 main span
Daily traffic
10
2009 count
Owner
State
State Park, Forest, or Reservation Agency

About this bridge

Forest Road 600 over Caspar Creek is a steel arch - deck carrying Forest Road 600 over Caspar Creek in Mendocino County, California. It was built in 1972, so it is 53 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 10 vehicles a day, projected to reach 12 by 2041. The structure is 32 ft (9.8 m) long. If it were closed, the detour would be 123.7 mi (199 km).

Location

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CarriesForest Road 600
CrossesCaspar Creek
LocationSouth of JCT With RD 620
RouteState Lands Road 0
CountyMendocino County
StateCalifornia
Coordinates39.34611, -123.75556
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
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.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMay 2023
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
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating44.6 US tons
Inventory rating26.8 US tons

Structure

Structure typeArch - Deck
MaterialSteel
DeckNot applicable
Main spans1
Design loadUnknown
Structure length32 ft (9.8 m)
Longest span31 ft (9.4 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10 (2009)
Projected traffic12 by 2041
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Forest Road 600 over Caspar Creek built?

It was built in 1972, making it 53 years old in 2025.

What condition is Forest Road 600 over Caspar 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 May 2023.

How much traffic does Forest Road 600 over Caspar Creek carry?

About 10 vehicles per day (2009 count).

How long is Forest Road 600 over Caspar Creek?

The structure is 32 ft (9.8 m) long with a longest span of 31 ft (9.4 m).

Who owns Forest Road 600 over Caspar Creek?

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