US Bridges

I 90 over RR

Fair

Missoula County, Montana · 5M W Missoula · Structure no. I00090096+09851

Built
1966
59 years old
Condition
Fair
inspected December 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
163 ft
3 main spans
Daily traffic
10,499
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over RR is a prestressed concrete stringer/multi-beam or girder carrying I 90 over RR in Missoula County, Montana. It was built in 1966, so it is 59 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 10,499 vehicles a day, roughly 11% of them trucks, projected to reach 11,024 by 2043. The structure is 163 ft (49.7 m) long and 39 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 90
CrossesRR
Location5M W Missoula
RouteInterstate 90
CountyMissoula County
StateMontana
Coordinates46.94532, -114.12085
Functional classUrban 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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionDecember 2023
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 geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating47 US tons
Inventory rating36 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length163 ft (49.7 m)
Longest span56 ft (17.1 m)
Deck width39 ft (11.9 m)
Roadway width38 ft (11.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,499 (2023)
Projected traffic11,024 by 2043
Trucks11%
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 proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 90 over RR built?

It was built in 1966, making it 59 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 December 2023.

How much traffic does I 90 over RR carry?

About 10,499 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is I 90 over RR?

The structure is 163 ft (49.7 m) long with a longest span of 56 ft (17.1 m) and a deck 39 ft wide.

Who owns I 90 over RR?

It is owned by the State Highway Agency.