US Bridges

I 15 over Prickly Pear Creek

Fair

Jefferson County, Montana · 1.2M S Clancy · Structure no. I00015180+08901

Built
1969
56 years old
Condition
Fair
inspected January 2025
Type
Slab
Concrete
Length
23 ft
1 main span
Daily traffic
5,987
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Prickly Pear Creek is a concrete slab carrying I 15 over Prickly Pear Creek in Jefferson County, Montana. It was built in 1969, so it is 56 years old, older 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 5 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 5,987 vehicles a day, roughly 12% of them trucks, projected to reach 6,286 by 2043. The structure is 23 ft (6.9 m) long and 117 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 15
CrossesPrickly Pear Creek
Location1.2M S Clancy
RouteInterstate 15
CountyJefferson County
StateMontana
Coordinates46.45087, -111.98667
Functional classRural Principal Arterial - Interstate

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.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Channel and channel protection7 GoodSome minor problems.
Last inspectionJanuary 2025
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry7: Better than present minimum criteria
Waterway adequacy7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating52.1 US tons
Inventory rating40 US tons

Structure

Structure typeSlab
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length23 ft (6.9 m)
Longest span21 ft (6.3 m)
Deck width117 ft (35.7 m)
Roadway width72 ft (21.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic5,987 (2023)
Projected traffic6,286 by 2043
Trucks12%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was I 15 over Prickly Pear Creek built?

It was built in 1969, making it 56 years old in 2025.

What condition is I 15 over Prickly Pear 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 January 2025.

How much traffic does I 15 over Prickly Pear Creek carry?

About 5,987 vehicles per day (2023 count), of which roughly 12% are trucks.

How long is I 15 over Prickly Pear Creek?

The structure is 23 ft (6.9 m) long with a longest span of 21 ft (6.3 m) and a deck 117 ft wide.

Who owns I 15 over Prickly Pear Creek?

It is owned by the State Highway Agency.