US Bridges

Grand Loop Road over Isa Lake

Good

Teton County, Wyoming · 9.8 Mi. NW of West Thumb · Structure no. 1570016P0000000

Built
2015
10 years old
Condition
Good
inspected September 2024
Type
Slab
Prestressed Concrete
Length
176 ft
6 main spans
Daily traffic
1,807
2019 count
Owner
Federal
National Park Service

About this bridge

Grand Loop Road over Isa Lake is a prestressed concrete slab carrying Grand Loop Road over Isa Lake in Teton County, Wyoming. It was built in 2015, so it is 10 years old, younger than the Wyoming average of 48.4 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 1,807 vehicles a day, roughly 1% of them trucks, projected to reach 2,168 by 2039. The structure is 176 ft (53.6 m) long and 36 ft wide. If it were closed, the detour would be 75.2 mi (121 km).

Location

Open in Google Maps
CarriesGrand Loop Road
CrossesIsa Lake
Location9.8 Mi. NW of West Thumb
RouteFederal Lands Road 10
CountyTeton County
StateWyoming
Coordinates44.44147, -110.71878
Functional classRural Minor Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating71 US tons
Inventory rating54 US tons

Structure

Structure typeSlab
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans6
Design loadHL 93
Structure length176 ft (53.6 m)
Longest span29 ft (8.8 m)
Deck width36 ft (11 m)
Roadway width32 ft (9.7 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 closed75.2 mi (121 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$30,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Grand Loop Road over Isa Lake built?

It was built in 2015, making it 10 years old in 2025.

What condition is Grand Loop Road over Isa Lake in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in September 2024.

How much traffic does Grand Loop Road over Isa Lake carry?

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

How long is Grand Loop Road over Isa Lake?

The structure is 176 ft (53.6 m) long with a longest span of 29 ft (8.8 m) and a deck 36 ft wide.

Who owns Grand Loop Road over Isa Lake?

It is owned by the National Park Service.