US Bridges

US 310 over RR

Fair

Yellowstone County, Montana · 1M S Laurel · Structure no. P00004052+06202

Built
2015
10 years old
Condition
Fair
inspected July 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
380 ft
3 main spans
Daily traffic
6,197
2023 count
Owner
State
State Highway Agency

About this bridge

US 310 over RR is a steel continuous stringer/multi-beam or girder carrying US 310 over RR in Yellowstone County, Montana. It was built in 2015, so it is 10 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 6,197 vehicles a day, roughly 4% of them trucks, projected to reach 6,723 by 2043. The structure is 380 ft (115.9 m) long and 44 ft wide. If it were closed, the detour would be 123.7 mi (199 km).

CarriesUS 310
CrossesRR
Location1M S Laurel
RouteState Highway 4
StateMontana
Coordinates45.64227, -108.7603
Functional classRural Principal Arterial - Other

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.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48 US tons
Inventory rating37 US tons

Structure

MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHL 93
Structure length380 ft (115.9 m)
Longest span160 ft (48.9 m)
Deck width44 ft (13.4 m)
Roadway width37 ft (11.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic6,197 (2023)
Projected traffic6,723 by 2043
Trucks4%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesRailroad
Detour if closed123.7 mi (199 km)
TollOn a free road
National Highway SystemYes

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 US 310 over RR built?

It was built in 2015, making it 10 years old in 2025.

What condition is US 310 over RR 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 July 2023.

How much traffic does US 310 over RR carry?

About 6,197 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is US 310 over RR?

The structure is 380 ft (115.9 m) long with a longest span of 160 ft (48.9 m) and a deck 44 ft wide.

Who owns US 310 over RR?

It is owned by the State Highway Agency.