US Bridges

IRR - S 382 over Flathead River

Fair

Sanders County, Montana · 1M E Perma · Structure no. S00382000+01001

Built
1965
60 years old
Condition
Fair
inspected November 2023
Type
Stringer/Multi-beam or Girder
Steel
Length
654 ft
5 main spans
Daily traffic
391
2023 count
Owner
State
State Highway Agency

About this bridge

IRR - S 382 over Flathead River is a steel stringer/multi-beam or girder carrying IRR - S 382 over Flathead River in Sanders County, Montana. It was built in 1965, so it is 60 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 391 vehicles a day, roughly 11% of them trucks, projected to reach 411 by 2043. The structure is 654 ft (199.2 m) long and 28 ft wide. If it were closed, the detour would be 39.8 mi (64 km).

Location

Open in Google Maps
CarriesIRR - S 382
CrossesFlathead River
Location1M E Perma
RouteState Highway 382
CountySanders County
StateMontana
Coordinates47.36745, -114.57737
Functional classRural Major Collector

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.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
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
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating32 US tons
Inventory rating25 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel
DeckConcrete, cast-in-place
Main spans5
Design loadHS 15
Structure length654 ft (199.2 m)
Longest span150 ft (45.7 m)
Deck width28 ft (8.5 m)
Roadway width24 ft (7.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic391 (2023)
Projected traffic411 by 2043
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed39.8 mi (64 km)
TollOn a free road
National Highway SystemNo

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—
NavigationNo navigation control on waterway

Frequently asked questions

When was IRR - S 382 over Flathead River built?

It was built in 1965, making it 60 years old in 2025.

What condition is IRR - S 382 over Flathead River 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 November 2023.

How much traffic does IRR - S 382 over Flathead River carry?

About 391 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is IRR - S 382 over Flathead River?

The structure is 654 ft (199.2 m) long with a longest span of 150 ft (45.7 m) and a deck 28 ft wide.

Who owns IRR - S 382 over Flathead River?

It is owned by the State Highway Agency.