US Bridges

Grand Loop Road over Firehole River

Fair

Teton County, Wyoming · 16 Mi. NW of West Thumb J · Structure no. 1570015P0000000

Built
1970
55 years old
Condition
Fair
inspected September 2024
Type
Tee Beam
Concrete Continuous
Length
166 ft
3 main spans
Daily traffic
1,807
2019 count
Owner
Federal
National Park Service

About this bridge

Grand Loop Road over Firehole River is a concrete continuous tee beam carrying Grand Loop Road over Firehole River in Teton County, Wyoming. It was built in 1970, so it is 55 years old, older than the Wyoming average of 48.4 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 1,807 vehicles a day, roughly 1% of them trucks, projected to reach 2,168 by 2039. The structure is 166 ft (50.7 m) long and 36 ft wide. If it were closed, the detour would be 78.9 mi (127 km).

Location

Open in Google Maps
CarriesGrand Loop Road
CrossesFirehole River
Location16 Mi. NW of West Thumb J
RouteFederal Lands Road 10
CountyTeton County
StateWyoming
Coordinates44.45386, -110.81975
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
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.9 US tons
Inventory rating29 US tons

Structure

Structure typeTee Beam
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length166 ft (50.7 m)
Longest span65 ft (19.7 m)
Deck width36 ft (11 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,807 (2019)
Projected traffic2,168 by 2039
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed78.9 mi (127 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerNational Park Service
Maintained byNational Park Service
Historic statusNot eligible for the National Register of Historic Places
Work proposedNone recorded
Estimated improvement cost$870,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Grand Loop Road over Firehole River built?

It was built in 1970, making it 55 years old in 2025.

What condition is Grand Loop Road over Firehole River 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 2024.

How much traffic does Grand Loop Road over Firehole River carry?

About 1,807 vehicles per day (2019 count), of which roughly 1% are trucks.

How long is Grand Loop Road over Firehole River?

The structure is 166 ft (50.7 m) long with a longest span of 65 ft (19.7 m) and a deck 36 ft wide.

Who owns Grand Loop Road over Firehole River?

It is owned by the National Park Service.