US Bridges

Wyo 120 over Alkali Lake

Fair

Park County, Wyoming · Thermopolis - Cody · Structure no. BQY

Built
1970
55 years old
Condition
Fair
inspected July 2023
Type
Frame
Concrete Continuous
Length
34 ft
1 main span
Daily traffic
2,675
2024 count
Owner
State
State Highway Agency

About this bridge

Wyo 120 over Alkali Lake is a concrete continuous frame carrying Wyo 120 over Alkali Lake in Park 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 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 2,675 vehicles a day, roughly 9% of them trucks, projected to reach 3,745 by 2043. The structure is 34 ft (10.4 m) long and 38 ft wide. If it were closed, the detour would be 70.8 mi (114 km).

Location

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CarriesWyo 120
CrossesAlkali Lake
LocationThermopolis - Cody
RouteState Highway 120
CountyPark County
StateWyoming
Coordinates44.50956, -109.02588
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
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
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 rating70.2 US tons
Inventory rating34.6 US tons

Structure

Structure typeFrame
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length34 ft (10.4 m)
Longest span30 ft (9.1 m)
Deck width38 ft (11.6 m)
Roadway width36 ft (11 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,675 (2024)
Projected traffic3,745 by 2043
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed70.8 mi (114 km)
TollOn a free road
National Highway SystemYes

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 Wyo 120 over Alkali Lake built?

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

What condition is Wyo 120 over Alkali Lake 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 July 2023.

How much traffic does Wyo 120 over Alkali Lake carry?

About 2,675 vehicles per day (2024 count), of which roughly 9% are trucks.

How long is Wyo 120 over Alkali Lake?

The structure is 34 ft (10.4 m) long with a longest span of 30 ft (9.1 m) and a deck 38 ft wide.

Who owns Wyo 120 over Alkali Lake?

It is owned by the State Highway Agency.