US Bridges

I 94 over Int Diamond Ring

Fair

Custer County, Montana · 21M NE Miles City · Structure no. I00094159+06481

Built
1971
54 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
128 ft
3 main spans
Daily traffic
2,137
2023 count
Owner
State
State Highway Agency

About this bridge

I 94 over Int Diamond Ring is a prestressed concrete stringer/multi-beam or girder carrying I 94 over Int Diamond Ring in Custer County, Montana. It was built in 1971, so it is 54 years old, older 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 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 2,137 vehicles a day, roughly 27% of them trucks, projected to reach 2,244 by 2043. The structure is 128 ft (39 m) long and 44 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 94
CrossesInt Diamond Ring
Location21M NE Miles City
RouteInterstate 94
CountyCuster County
StateMontana
Coordinates46.61578, -105.53942
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating88 US tons
Inventory rating57 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length128 ft (39 m)
Longest span56 ft (17.1 m)
Deck width44 ft (13.5 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,137 (2023)
Projected traffic2,244 by 2043
Trucks27%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 94 over Int Diamond Ring built?

It was built in 1971, making it 54 years old in 2025.

What condition is I 94 over Int Diamond Ring 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 I 94 over Int Diamond Ring carry?

About 2,137 vehicles per day (2023 count), of which roughly 27% are trucks.

How long is I 94 over Int Diamond Ring?

The structure is 128 ft (39 m) long with a longest span of 56 ft (17.1 m) and a deck 44 ft wide.

Who owns I 94 over Int Diamond Ring?

It is owned by the State Highway Agency.