US Bridges

I 15 over Little Prickly Pear CR

Good

Lewis and Clark County, Montana · 2M NW Seiben Int · Structure no. I00015218+06001

Built
1965
60 years old
Condition
Good
inspected April 2024
Type
Culvert
Steel
Length
25 ft
1 main span
Daily traffic
4,806
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 over Little Prickly Pear CR is a steel culvert carrying I 15 over Little Prickly Pear CR in Lewis and Clark County, Montana. It was built in 1965, so it is 60 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 4,806 vehicles a day, roughly 23% of them trucks, projected to reach 5,215 by 2043. The structure is 25 ft (7.7 m) long. If it were closed, the detour would be 67.7 mi (109 km).

CarriesI 15
CrossesLittle Prickly Pear CR
Location2M NW Seiben Int
RouteInterstate 15
StateMontana
Coordinates46.91327, -112.11655
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
Channel and channel protection7 GoodSome minor problems.
Culvert7 GoodSome minor problems.
Last inspectionApril 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating99 US tons
Inventory rating99 US tons

Structure

Structure typeCulvert
MaterialSteel
DeckNot applicable
Main spans1
Design loadHS 20
Structure length25 ft (7.7 m)
Longest span25 ft (7.7 m)
Deck width0 ft (0 m)
Roadway width0 ft (0 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic4,806 (2023)
Projected traffic5,215 by 2043
Trucks23%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed67.7 mi (109 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 Little Prickly Pear CR built?

It was built in 1965, making it 60 years old in 2025.

What condition is I 15 over Little Prickly Pear CR 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 April 2024.

How much traffic does I 15 over Little Prickly Pear CR carry?

About 4,806 vehicles per day (2023 count), of which roughly 23% are trucks.

How long is I 15 over Little Prickly Pear CR?

The structure is 25 ft (7.7 m) long with a longest span of 25 ft (7.7 m).

Who owns I 15 over Little Prickly Pear CR?

It is owned by the State Highway Agency.