US Bridges

I 90 over Sep Local Road

Fair

Mineral County, Montana · 5M E Lookout Pass · Structure no. I00090005+01481

Built
1973
52 years old, rebuilt 2007
Condition
Fair
inspected June 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
304 ft
3 main spans
Daily traffic
7,824
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Sep Local Road is a prestressed concrete stringer/multi-beam or girder carrying I 90 over Sep Local Road in Mineral County, Montana. It was built in 1973 and reconstructed in 2007, so it is 52 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 7,824 vehicles a day, roughly 25% of them trucks, projected to reach 8,215 by 2043. The structure is 304 ft (92.8 m) long and 84 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 90
CrossesSep Local Road
Location5M E Lookout Pass
RouteInterstate 90
CountyMineral County
StateMontana
Coordinates47.41906, -115.6173
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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating61.9 US tons
Inventory rating48 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length304 ft (92.8 m)
Longest span102 ft (31.1 m)
Deck width84 ft (25.6 m)
Roadway width81 ft (24.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic7,824 (2023)
Projected traffic8,215 by 2043
Trucks25%
Lanes on structure4
Traffic directionTwo-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 Local Road built?

It was built in 1973, making it 52 years old in 2025. It was reconstructed in 2007.

What condition is I 90 over Sep Local 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 2023.

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

About 7,824 vehicles per day (2023 count), of which roughly 25% are trucks.

How long is I 90 over Sep Local Road?

The structure is 304 ft (92.8 m) long with a longest span of 102 ft (31.1 m) and a deck 84 ft wide.

Who owns I 90 over Sep Local Road?

It is owned by the State Highway Agency.