US Bridges

I 90 over Sep Loiselle Road

Fair

Missoula County, Montana · 3.7M E Frenchtown · Structure no. I00090093+03972

Built
1971
54 years old
Condition
Fair
inspected June 2024
Type
Slab
Concrete Continuous
Length
79 ft
3 main spans
Daily traffic
6,073
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Sep Loiselle Road is a concrete continuous slab carrying I 90 over Sep Loiselle Road in Missoula 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 6,073 vehicles a day, roughly 15% of them trucks, projected to reach 6,376 by 2043. The structure is 79 ft (24.1 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 90
CrossesSep Loiselle Road
Location3.7M E Frenchtown
RouteInterstate 90
CountyMissoula County
StateMontana
Coordinates46.98134, -114.17455
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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2024
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 rating44 US tons
Inventory rating34 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length79 ft (24.1 m)
Longest span28 ft (8.4 m)
Deck width44 ft (13.4 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,073 (2023)
Projected traffic6,376 by 2043
Trucks15%
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 90 over Sep Loiselle Road built?

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

What condition is I 90 over Sep Loiselle Road 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 June 2024.

How much traffic does I 90 over Sep Loiselle Road carry?

About 6,073 vehicles per day (2023 count), of which roughly 15% are trucks.

How long is I 90 over Sep Loiselle Road?

The structure is 79 ft (24.1 m) long with a longest span of 28 ft (8.4 m) and a deck 44 ft wide.

Who owns I 90 over Sep Loiselle Road?

It is owned by the State Highway Agency.