US Bridges

US 12 over Drainage

Good

Musselshell County, Montana · 12M W Roundup · Structure no. P00014157+07001

Built
2006
19 years old
Condition
Good
inspected December 2023
Type
Culvert
Steel
Length
27 ft
2 main spans
Daily traffic
441
2023 count
Owner
State
State Highway Agency

About this bridge

US 12 over Drainage is a steel culvert carrying US 12 over Drainage in Musselshell County, Montana. It was built in 2006, so it is 19 years old, younger 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 441 vehicles a day, roughly 13% of them trucks, projected to reach 463 by 2043. The structure is 27 ft (8.1 m) long. If it were closed, the detour would be 123.7 mi (199 km).

CarriesUS 12
CrossesDrainage
Location12M W Roundup
RouteU.S. Route 12
StateMontana
Coordinates46.33516, -108.70687
Functional classRural Minor Arterial

Condition and inspection

Good

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

ComponentRatingMeaning
Channel and channel protection8 Very GoodNo problems noted.
Culvert7 GoodSome minor problems.
Last inspectionDecember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Waterway adequacy6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating110.1 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans2
Design loadHS 20
Structure length27 ft (8.1 m)
Longest span11 ft (3.3 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic441 (2023)
Projected traffic463 by 2043
Trucks13%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesRelief for waterway
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 US 12 over Drainage built?

It was built in 2006, making it 19 years old in 2025.

What condition is US 12 over Drainage 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 December 2023.

How much traffic does US 12 over Drainage carry?

About 441 vehicles per day (2023 count), of which roughly 13% are trucks.

How long is US 12 over Drainage?

The structure is 27 ft (8.1 m) long with a longest span of 11 ft (3.3 m).

Who owns US 12 over Drainage?

It is owned by the State Highway Agency.