US Bridges

I 84B over I 84;W.MOUNTAIN Home Ic

Fair

Elmore County, Idaho · 3.0 W. Mountain Home · Structure no. 000000000013755

Built
1970
55 years old
Condition
Fair
inspected March 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
320 ft
2 main spans
Daily traffic
2,500
2023 count
Owner
State
State Highway Agency

About this bridge

I 84B over I 84;W.MOUNTAIN Home Ic is a steel continuous stringer/multi-beam or girder carrying I 84B over I 84;W.MOUNTAIN Home Ic in Elmore County, Idaho. It was built in 1970, so it is 55 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 2,500 vehicles a day, roughly 11% of them trucks, projected to reach 3,750 by 2042. The structure is 320 ft (97.5 m) long and 51 ft wide.

Location

Open in Google Maps
CarriesI 84B
CrossesI 84;W.MOUNTAIN Home Ic
Location3.0 W. Mountain Home
RouteInterstate 84
CountyElmore County
StateIdaho
Coordinates43.17397, -115.74703
Functional classUrban Minor Arterial

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionMarch 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating53 US tons
Inventory rating32 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2 (+2 approach)
Design loadHS 20
Structure length320 ft (97.5 m)
Longest span132 ft (40.2 m)
Deck width51 ft (15.5 m)
Roadway width48 ft (14.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,500 (2023)
Projected traffic3,750 by 2042
Trucks11%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed—
TollOn a free road
National Highway SystemYes

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 84B over I 84;W.MOUNTAIN Home Ic built?

It was built in 1970, making it 55 years old in 2025.

What condition is I 84B over I 84;W.MOUNTAIN Home 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 March 2023.

How much traffic does I 84B over I 84;W.MOUNTAIN Home Ic carry?

About 2,500 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is I 84B over I 84;W.MOUNTAIN Home Ic?

The structure is 320 ft (97.5 m) long with a longest span of 132 ft (40.2 m) and a deck 51 ft wide.

Who owns I 84B over I 84;W.MOUNTAIN Home Ic?

It is owned by the State Highway Agency.