US Bridges

I 15 Nbl over Humphrey Road Ic

Fair

Clark County, Idaho · At Humphrey · Structure no. 000000000011985

Built
1966
59 years old
Condition
Fair
inspected August 2024
Type
Stringer/Multi-beam or Girder
Concrete
Length
114 ft
3 main spans
Daily traffic
1,750
2023 count
Owner
State
State Highway Agency

About this bridge

I 15 Nbl over Humphrey Road Ic is a concrete stringer/multi-beam or girder carrying I 15 Nbl over Humphrey Road Ic in Clark County, Idaho. It was built in 1966, so it is 59 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 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 1,750 vehicles a day, roughly 35% of them trucks, projected to reach 2,625 by 2042. The structure is 114 ft (34.7 m) long and 52 ft wide.

Location

Open in Google Maps
CarriesI 15 Nbl
CrossesHumphrey Road Ic
LocationAt Humphrey
RouteInterstate 15
CountyClark County
StateIdaho
Coordinates44.48714, -112.23503
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Last inspectionAugust 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating40 US tons
Inventory rating24 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialConcrete
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20
Structure length114 ft (34.7 m)
Longest span37 ft (11.3 m)
Deck width52 ft (16 m)
Roadway width51 ft (15.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,750 (2023)
Projected traffic2,625 by 2042
Trucks35%
Lanes on structure2
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed—
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$191,000 (2023 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I 15 Nbl over Humphrey Road Ic built?

It was built in 1966, making it 59 years old in 2025.

What condition is I 15 Nbl over Humphrey Road Ic 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 August 2024.

How much traffic does I 15 Nbl over Humphrey Road Ic carry?

About 1,750 vehicles per day (2023 count), of which roughly 35% are trucks.

How long is I 15 Nbl over Humphrey Road Ic?

The structure is 114 ft (34.7 m) long with a longest span of 37 ft (11.3 m) and a deck 52 ft wide.

Who owns I 15 Nbl over Humphrey Road Ic?

It is owned by the State Highway Agency.