US Bridges

Ager RD over Black Mountain Gulch

Fair

Siskiyou County, California · 7.6 MI North SR 3 · Structure no. 02C0232

Built
1980
45 years old
Condition
Fair
inspected August 2024
Type
Slab
Concrete Continuous
Length
47 ft
2 main spans
Daily traffic
648
2020 count
Owner
County
County Highway Agency

About this bridge

Ager RD over Black Mountain Gulch is a concrete continuous slab carrying Ager RD over Black Mountain Gulch in Siskiyou County, California. It was built in 1980, so it is 45 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 6 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 648 vehicles a day, roughly 30% of them trucks, projected to reach 1,087 by 2041. The structure is 47 ft (14.2 m) long and 33 ft wide. If it were closed, the detour would be 14.9 mi (24 km).

Location

Open in Google Maps
CarriesAger RD
CrossesBlack Mountain Gulch
Location7.6 MI North SR 3
RouteCounty Highway 0
CountySiskiyou County
StateCalifornia
Coordinates41.82742, -122.49361
Functional classRural Major 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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment7: Better than present minimum criteria
Operating rating55.7 US tons
Inventory rating42.9 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length47 ft (14.2 m)
Longest span22 ft (6.7 m)
Deck width33 ft (10 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic648 (2020)
Projected traffic1,087 by 2041
Trucks30%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed14.9 mi (24 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 Ager RD over Black Mountain Gulch built?

It was built in 1980, making it 45 years old in 2025.

What condition is Ager RD over Black Mountain Gulch 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 August 2024.

How much traffic does Ager RD over Black Mountain Gulch carry?

About 648 vehicles per day (2020 count), of which roughly 30% are trucks.

How long is Ager RD over Black Mountain Gulch?

The structure is 47 ft (14.2 m) long with a longest span of 22 ft (6.7 m) and a deck 33 ft wide.

Who owns Ager RD over Black Mountain Gulch?

It is owned by the County Highway Agency.