US Bridges

Diamond Mtn RD over Lights Creek

Fair

Plumas County, California · 9.4 MI NE Beckwrth-Grn RD · Structure no. 09C0068

Built
1997
28 years old
Condition
Fair
inspected September 2023
Type
Slab
Concrete
Length
47 ft
1 main span
Daily traffic
80
2019 count
Owner
County
County Highway Agency

About this bridge

Diamond Mtn RD over Lights Creek is a concrete slab carrying Diamond Mtn RD over Lights Creek in Plumas County, California. It was built in 1997, so it is 28 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 80 vehicles a day, roughly 4% of them trucks, projected to reach 262 by 2044. The structure is 47 ft (14.2 m) long and 27 ft wide. If it were closed, the detour would be 16.2 mi (26 km).

Location

Open in Google Maps
CarriesDiamond Mtn RD
CrossesLights Creek
Location9.4 MI NE Beckwrth-Grn RD
RouteCounty Highway 0
CountyPlumas County
StateCalifornia
Coordinates40.20506, -120.77248
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
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.
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 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 geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating60.4 US tons
Inventory rating43.2 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length47 ft (14.2 m)
Longest span47 ft (14.2 m)
Deck width27 ft (8.1 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic80 (2019)
Projected traffic262 by 2044
Trucks4%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed16.2 mi (26 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 Diamond Mtn RD over Lights Creek built?

It was built in 1997, making it 28 years old in 2025.

What condition is Diamond Mtn RD over Lights 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 Diamond Mtn RD over Lights Creek carry?

About 80 vehicles per day (2019 count), of which roughly 4% are trucks.

How long is Diamond Mtn RD over Lights Creek?

The structure is 47 ft (14.2 m) long with a longest span of 47 ft (14.2 m) and a deck 27 ft wide.

Who owns Diamond Mtn RD over Lights Creek?

It is owned by the County Highway Agency.