US Bridges

Lone Mountain RD over Little Rock Creek

FairPosted for load

Josephine County, Oregon · T40S-R9W-S26 · Structure no. 555010555000020

Built
1954
71 years old
Condition
Fair
inspected October 2024
Type
Culvert
Concrete Continuous
Length
26 ft
2 main spans
Daily traffic
198
2020 count
Owner
County
County Highway Agency

About this bridge

Lone Mountain RD over Little Rock Creek is a concrete continuous culvert carrying Lone Mountain RD over Little Rock Creek in Josephine County, Oregon. It was built in 1954, so it is 71 years old, older than the Oregon average of 49.9 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. Its operating status is: posted for other load-capacity restriction.

It carries about 198 vehicles a day, roughly 10% of them trucks, projected to reach 233 by 2025. The structure is 26 ft (7.9 m) long and 25 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

CarriesLone Mountain RD
CrossesLittle Rock Creek
LocationT40S-R9W-S26
RouteCounty Highway C5550
StateOregon
Coordinates42.0652, -123.7243
Functional classRural Minor 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
Channel and channel protection7 GoodSome minor problems.
Culvert6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusPosted for other load-capacity restriction
ScourUnknown foundation; not evaluated for scour
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating27.1 US tons
Inventory rating20.9 US tons

Structure

Structure typeCulvert
MaterialConcrete Continuous
DeckNot applicable
Main spans2
Design loadHS 20
Structure length26 ft (7.9 m)
Longest span12 ft (3.7 m)
Deck width25 ft (7.6 m)
Roadway width23 ft (6.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic198 (2020)
Projected traffic233 by 2025
Trucks10%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 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 Lone Mountain RD over Little Rock Creek built?

It was built in 1954, making it 71 years old in 2025.

What condition is Lone Mountain RD over Little Rock 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 October 2024.

How much traffic does Lone Mountain RD over Little Rock Creek carry?

About 198 vehicles per day (2020 count), of which roughly 10% are trucks.

How long is Lone Mountain RD over Little Rock Creek?

The structure is 26 ft (7.9 m) long with a longest span of 12 ft (3.7 m) and a deck 25 ft wide.

Who owns Lone Mountain RD over Little Rock Creek?

It is owned by the County Highway Agency.