US Bridges

S 78 over Whitebird Creek

Fair

Stillwater County, Montana · 6M NE Absarokee · Structure no. P00078039+06001

Built
2007
18 years old
Condition
Fair
inspected September 2023
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
94 ft
1 main span
Daily traffic
2,376
2023 count
Owner
State
State Highway Agency

About this bridge

S 78 over Whitebird Creek is a prestressed concrete stringer/multi-beam or girder carrying S 78 over Whitebird Creek in Stillwater County, Montana. It was built in 2007, so it is 18 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 2,376 vehicles a day, roughly 6% of them trucks, projected to reach 2,542 by 2043. The structure is 94 ft (28.8 m) long and 42 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

Location

Open in Google Maps
CarriesS 78
CrossesWhitebird Creek
Location6M NE Absarokee
RouteState Highway 78
CountyStillwater County
StateMontana
Coordinates45.56901, -109.33285
Functional classRural Minor Arterial

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating49.1 US tons
Inventory rating38 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length94 ft (28.8 m)
Longest span92 ft (28 m)
Deck width42 ft (12.8 m)
Roadway width40 ft (12.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,376 (2023)
Projected traffic2,542 by 2043
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed123.7 mi (199 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 S 78 over Whitebird Creek built?

It was built in 2007, making it 18 years old in 2025.

What condition is S 78 over Whitebird Creek 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 September 2023.

How much traffic does S 78 over Whitebird Creek carry?

About 2,376 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is S 78 over Whitebird Creek?

The structure is 94 ft (28.8 m) long with a longest span of 92 ft (28 m) and a deck 42 ft wide.

Who owns S 78 over Whitebird Creek?

It is owned by the State Highway Agency.