US Bridges

I 90 over Lost Creek

Fair

Deer Lodge County, Montana · 2.5M N Warm Springs · Structure no. I00090198+09371

Built
1978
47 years old
Condition
Fair
inspected February 2024
Type
Slab
Concrete
Length
27 ft
1 main span
Daily traffic
11,628
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Lost Creek is a concrete slab carrying I 90 over Lost Creek in Deer Lodge County, Montana. It was built in 1978, so it is 47 years old, younger than the Montana average of 47 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 11,628 vehicles a day, roughly 16% of them trucks, projected to reach 12,616 by 2043. The structure is 27 ft (8.2 m) long and 132 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 90
CrossesLost Creek
Location2.5M N Warm Springs
RouteInterstate 90
CountyDeer Lodge County
StateMontana
Coordinates46.21848, -112.77326
Functional classRural Principal Arterial - Interstate

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.
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 inspectionFebruary 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 geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating50 US tons
Inventory rating38 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length27 ft (8.2 m)
Longest span25 ft (7.6 m)
Deck width132 ft (40.2 m)
Roadway width78 ft (23.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic11,628 (2023)
Projected traffic12,616 by 2043
Trucks16%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState 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 I 90 over Lost Creek built?

It was built in 1978, making it 47 years old in 2025.

What condition is I 90 over Lost 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 February 2024.

How much traffic does I 90 over Lost Creek carry?

About 11,628 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is I 90 over Lost Creek?

The structure is 27 ft (8.2 m) long with a longest span of 25 ft (7.6 m) and a deck 132 ft wide.

Who owns I 90 over Lost Creek?

It is owned by the State Highway Agency.