US Bridges

US 20 over Fall River

Fair

Fremont County, Idaho · 1 N. Chester · Structure no. 000000000012665

Built
1963
62 years old
Condition
Fair
inspected September 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
114 ft
2 main spans
Daily traffic
8,000
2023 count
Owner
State
State Highway Agency

About this bridge

US 20 over Fall River is a prestressed concrete stringer/multi-beam or girder carrying US 20 over Fall River in Fremont County, Idaho. It was built in 1963, so it is 62 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 8,000 vehicles a day, roughly 21% of them trucks, projected to reach 12,000 by 2042. The structure is 114 ft (34.7 m) long and 42 ft wide. If it were closed, the detour would be 39.8 mi (64 km).

Location

Open in Google Maps
CarriesUS 20
CrossesFall River
Location1 N. Chester
RouteU.S. Route 20
CountyFremont County
StateIdaho
Coordinates44.0075, -111.54628
Functional classRural Principal Arterial - Other

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 inspectionSeptember 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation5: Somewhat better than minimum adequacy to tolerate being left in place as is
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating71 US tons
Inventory rating42 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 20
Structure length114 ft (34.7 m)
Longest span55 ft (16.8 m)
Deck width42 ft (12.8 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic8,000 (2023)
Projected traffic12,000 by 2042
Trucks21%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed39.8 mi (64 km)
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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$1.8 million (2020 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 20 over Fall River built?

It was built in 1963, making it 62 years old in 2025.

What condition is US 20 over Fall River 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 2024.

How much traffic does US 20 over Fall River carry?

About 8,000 vehicles per day (2023 count), of which roughly 21% are trucks.

How long is US 20 over Fall River?

The structure is 114 ft (34.7 m) long with a longest span of 55 ft (16.8 m) and a deck 42 ft wide.

Who owns US 20 over Fall River?

It is owned by the State Highway Agency.