US Bridges

I 90 over RR

Fair

Missoula County, Montana · 1.9M W Clinton · Structure no. I00090118+06292

Built
1963
62 years old
Condition
Fair
inspected May 2024
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
355 ft
3 main spans
Daily traffic
5,626
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over RR is a steel continuous stringer/multi-beam or girder carrying I 90 over RR in Missoula County, Montana. It was built in 1963, so it is 62 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 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 5,626 vehicles a day, roughly 20% of them trucks, projected to reach 5,907 by 2043. The structure is 355 ft (108.3 m) long and 32 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 90
CrossesRR
Location1.9M W Clinton
RouteInterstate 90
CountyMissoula County
StateMontana
Coordinates46.79544, -113.75165
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
Deck7 GoodSome minor problems.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure7 GoodSome minor problems.
Last inspectionMay 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment8: Equal to present desirable criteria
Operating rating42 US tons
Inventory rating33 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3 (+3 approach)
Design loadHS 20
Structure length355 ft (108.3 m)
Longest span71 ft (21.6 m)
Deck width32 ft (9.7 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,626 (2023)
Projected traffic5,907 by 2043
Trucks20%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1 million
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 90 over RR built?

It was built in 1963, making it 62 years old in 2025.

What condition is I 90 over RR 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 May 2024.

How much traffic does I 90 over RR carry?

About 5,626 vehicles per day (2023 count), of which roughly 20% are trucks.

How long is I 90 over RR?

The structure is 355 ft (108.3 m) long with a longest span of 71 ft (21.6 m) and a deck 32 ft wide.

Who owns I 90 over RR?

It is owned by the State Highway Agency.