US Bridges

I 15 Sbl over Blackrock Rd.Gs

Fair

Bannock County, Idaho · 4.6 W. Inkom · Structure no. 000000000011200

Built
1965
60 years old
Condition
Fair
inspected September 2021
Type
Frame
Concrete
Length
28 ft
1 main span
Daily traffic
9,750
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 Sbl over Blackrock Rd.Gs is a concrete frame carrying I 15 Sbl over Blackrock Rd.Gs in Bannock County, Idaho. It was built in 1965, so it is 60 years old, older than the Idaho average of 45.3 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 9,750 vehicles a day, roughly 20% of them trucks, projected to reach 14,625 by 2042. The structure is 28 ft (8.5 m) long and 46 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesI 15 Sbl
CrossesBlackrock Rd.Gs
Location4.6 W. Inkom
RouteInterstate 15
CountyBannock County
StateIdaho
Coordinates42.79868, -112.341
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.
Substructure7 GoodSome minor problems.
Last inspectionSeptember 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating70 US tons
Inventory rating42 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length28 ft (8.5 m)
Longest span28 ft (8.5 m)
Deck width46 ft (14 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic9,750 (2023)
Projected traffic14,625 by 2042
Trucks20%
Lanes on structure2
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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 statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 15 Sbl over Blackrock Rd.Gs built?

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

What condition is I 15 Sbl over Blackrock Rd.Gs 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 September 2021.

How much traffic does I 15 Sbl over Blackrock Rd.Gs carry?

About 9,750 vehicles per day (2023 count), of which roughly 20% are trucks.

How long is I 15 Sbl over Blackrock Rd.Gs?

The structure is 28 ft (8.5 m) long with a longest span of 28 ft (8.5 m) and a deck 46 ft wide.

Who owns I 15 Sbl over Blackrock Rd.Gs?

It is owned by the State Highway Agency.