US Bridges

I 90 over Sep Perkins Lane

Fair

Deer Lodge County, Montana · 1.9M N Warm Springs · Structure no. I00090199+06471

Built
1978
47 years old
Condition
Fair
inspected February 2024
Type
Slab
Concrete Continuous
Length
78 ft
3 main spans
Daily traffic
5,814
2023 count
Owner
State
State Highway Agency

About this bridge

I 90 over Sep Perkins Lane is a concrete continuous slab carrying I 90 over Sep Perkins Lane in Deer Lodge County, Montana. It was built in 1978, so it is 47 years old, younger 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 5,814 vehicles a day, roughly 16% of them trucks, projected to reach 6,308 by 2043. The structure is 78 ft (23.8 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 Perkins Lane
Location1.9M N Warm Springs
RouteInterstate 90
CountyDeer Lodge County
StateMontana
Coordinates46.20856, -112.77731
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionFebruary 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 rating38 US tons
Inventory rating29 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length78 ft (23.8 m)
Longest span30 ft (9.1 m)
Deck width44 ft (13.5 m)
Roadway width42 ft (12.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,814 (2023)
Projected traffic6,308 by 2043
Trucks16%
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 Perkins Lane built?

It was built in 1978, making it 47 years old in 2025.

What condition is I 90 over Sep Perkins Lane 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 February 2024.

How much traffic does I 90 over Sep Perkins Lane carry?

About 5,814 vehicles per day (2023 count), of which roughly 16% are trucks.

How long is I 90 over Sep Perkins Lane?

The structure is 78 ft (23.8 m) long with a longest span of 30 ft (9.1 m) and a deck 44 ft wide.

Who owns I 90 over Sep Perkins Lane?

It is owned by the State Highway Agency.