US Bridges

I 15 over Int Buxton-Buxton RD

Good

Silver Bow County, Montana · 5.6M S Rocker · Structure no. I00015116+03162

Built
1976
49 years old
Condition
Good
inspected November 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
128 ft
3 main spans
Daily traffic
2,570
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Int Buxton-Buxton RD is a prestressed concrete stringer/multi-beam or girder carrying I 15 over Int Buxton-Buxton RD in Silver Bow County, Montana. It was built in 1976, so it is 49 years old, older than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 2,570 vehicles a day, roughly 18% of them trucks, projected to reach 2,775 by 2043. The structure is 128 ft (39 m) long and 44 ft wide.

CarriesI 15
CrossesInt Buxton-Buxton RD
Location5.6M S Rocker
RouteInterstate 15
StateMontana
Coordinates45.94381, -112.66891
Functional classRural Principal Arterial - Interstate

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionNovember 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 rating48 US tons
Inventory rating27 US tons

Structure

MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length128 ft (39 m)
Longest span65 ft (19.8 m)
Deck width44 ft (13.4 m)
Roadway width41 ft (12.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,570 (2023)
Projected traffic2,775 by 2043
Trucks18%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed—
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 15 over Int Buxton-Buxton RD built?

It was built in 1976, making it 49 years old in 2025.

What condition is I 15 over Int Buxton-Buxton RD in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in November 2024.

How much traffic does I 15 over Int Buxton-Buxton RD carry?

About 2,570 vehicles per day (2023 count), of which roughly 18% are trucks.

How long is I 15 over Int Buxton-Buxton RD?

The structure is 128 ft (39 m) long with a longest span of 65 ft (19.8 m) and a deck 44 ft wide.

Who owns I 15 over Int Buxton-Buxton RD?

It is owned by the State Highway Agency.