US Bridges

US 20B over Salem Union Canal

Fair

Fremont County, Idaho · 1.5 N. St. Anthony · Structure no. 000000000012746

Built
1994
31 years old
Condition
Fair
inspected March 2024
Type
Frame
Concrete
Length
44 ft
2 main spans
Daily traffic
1,400
2023 count
Owner
State
State Highway Agency

About this bridge

US 20B over Salem Union Canal is a concrete frame carrying US 20B over Salem Union Canal in Fremont County, Idaho. It was built in 1994, so it is 31 years old, younger 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 1,400 vehicles a day, roughly 9% of them trucks, projected to reach 2,100 by 2042. The structure is 44 ft (13.3 m) long and 40 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesUS 20B
CrossesSalem Union Canal
Location1.5 N. St. Anthony
RouteU.S. Route 20
CountyFremont County
StateIdaho
Coordinates43.97219, -111.65042
Functional classRural Major Collector

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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMarch 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating108 US tons
Inventory rating64 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans2
Design loadHS 25 or greater
Structure length44 ft (13.3 m)
Longest span21 ft (6.5 m)
Deck width40 ft (12.2 m)
Roadway width32 ft (9.7 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,400 (2023)
Projected traffic2,100 by 2042
Trucks9%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemNo

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—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 20B over Salem Union Canal built?

It was built in 1994, making it 31 years old in 2025.

What condition is US 20B over Salem Union Canal 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 2024.

How much traffic does US 20B over Salem Union Canal carry?

About 1,400 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is US 20B over Salem Union Canal?

The structure is 44 ft (13.3 m) long with a longest span of 21 ft (6.5 m) and a deck 40 ft wide.

Who owns US 20B over Salem Union Canal?

It is owned by the State Highway Agency.