US Bridges

Old US 10 over Big Ditch 051

Poor

Yellowstone County, Montana · 4M W Laurel · Structure no. L56787001+02001

Built
1932
93 years old
Condition
Poor
inspected January 2025
Type
Tee Beam
Concrete
Length
65 ft
2 main spans
Daily traffic
2,489
2023 count
Owner
State
State Highway Agency

About this bridge

Old US 10 over Big Ditch 051 is a concrete tee beam carrying Old US 10 over Big Ditch 051 in Yellowstone County, Montana. It was built in 1932, so it is 93 years old, older than the Montana average of 47 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 3 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

It carries about 2,489 vehicles a day, projected to reach 2,738 by 2043. The structure is 65 ft (19.8 m) long and 25 ft wide. If it were closed, the detour would be 11.8 mi (19 km).

Location

Open in Google Maps
CarriesOld US 10
CrossesBig Ditch 051
Location4M W Laurel
RouteState Highway 81015
CountyYellowstone County
StateMontana
Coordinates45.66842, -108.85797
Functional classRural Major Collector

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure3 SeriousLoss of section, deterioration, spalling or scour have seriously affected primary structural components.
Channel and channel protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation3: Basically intolerable, requiring high priority of corrective action
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating29 US tons
Inventory rating22 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans2
Design loadH 15
Structure length65 ft (19.8 m)
Longest span31 ft (9.4 m)
Deck width25 ft (7.7 m)
Roadway width22 ft (6.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,489 (2023)
Projected traffic2,738 by 2043
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed11.8 mi (19 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 Old US 10 over Big Ditch 051 built?

It was built in 1932, making it 93 years old in 2025.

What condition is Old US 10 over Big Ditch 051 in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in January 2025.

How much traffic does Old US 10 over Big Ditch 051 carry?

About 2,489 vehicles per day (2023 count).

How long is Old US 10 over Big Ditch 051?

The structure is 65 ft (19.8 m) long with a longest span of 31 ft (9.4 m) and a deck 25 ft wide.

Who owns Old US 10 over Big Ditch 051?

It is owned by the State Highway Agency.