US Bridges

US 91 over Ross Fork Creek

Fair

Bingham County, Idaho · 0.5 S. Fort Hall · Structure no. 000000000017515

Built
1925
100 years old, rebuilt 1949
Condition
Fair
inspected March 2024
Type
Tee Beam
Concrete
Length
29 ft
1 main span
Daily traffic
3,800
2023 count
Owner
State
State Highway Agency

About this bridge

US 91 over Ross Fork Creek is a concrete tee beam carrying US 91 over Ross Fork Creek in Bingham County, Idaho. It was built in 1925 and reconstructed in 1949, so it is 100 years old, older than the Idaho average of 45.3 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 3,800 vehicles a day, roughly 11% of them trucks, projected to reach 5,700 by 2042. The structure is 29 ft (8.8 m) long and 34 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

CarriesUS 91
CrossesRoss Fork Creek
Location0.5 S. Fort Hall
RouteU.S. Route 91
StateIdaho
Coordinates43.02208, -112.43867
Functional classRural Principal Arterial - Other

Condition and inspection

Fair

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

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMarch 2024
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 geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating73 US tons
Inventory rating43 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadH 15
Structure length29 ft (8.8 m)
Longest span27 ft (8.2 m)
Deck width34 ft (10.5 m)
Roadway width32 ft (9.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,800 (2023)
Projected traffic5,700 by 2042
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 91 over Ross Fork Creek built?

It was built in 1925, making it 100 years old in 2025. It was reconstructed in 1949.

What condition is US 91 over Ross Fork 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 March 2024.

How much traffic does US 91 over Ross Fork Creek carry?

About 3,800 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is US 91 over Ross Fork Creek?

The structure is 29 ft (8.8 m) long with a longest span of 27 ft (8.2 m) and a deck 34 ft wide.

Who owns US 91 over Ross Fork Creek?

It is owned by the State Highway Agency.