US Bridges

US 20 over Anderson Canal

Fair

Bonneville County, Idaho · 3.8 N. Idaho Falls · Structure no. 000000000012380

Built
1970
55 years old
Condition
Fair
inspected November 2024
Type
Frame
Concrete
Length
24 ft
1 main span
Daily traffic
27,000
2023 count
Owner
State
State Highway Agency

About this bridge

US 20 over Anderson Canal is a concrete frame carrying US 20 over Anderson Canal in Bonneville 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 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 27,000 vehicles a day, roughly 9% of them trucks, projected to reach 40,500 by 2042. The structure is 24 ft (7.3 m) long and 107 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesUS 20
CrossesAnderson Canal
Location3.8 N. Idaho Falls
RouteU.S. Route 20
CountyBonneville County
StateIdaho
Coordinates43.55658, -111.99269
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.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection7 GoodSome minor problems.
Last inspectionNovember 2024
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating73 US tons
Inventory rating43 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length24 ft (7.3 m)
Longest span24 ft (7.3 m)
Deck width107 ft (32.6 m)
Roadway width105 ft (31.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic27,000 (2023)
Projected traffic40,500 by 2042
Trucks9%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.2 mi (2 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 proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 20 over Anderson Canal built?

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

What condition is US 20 over Anderson 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 November 2024.

How much traffic does US 20 over Anderson Canal carry?

About 27,000 vehicles per day (2023 count), of which roughly 9% are trucks.

How long is US 20 over Anderson Canal?

The structure is 24 ft (7.3 m) long with a longest span of 24 ft (7.3 m) and a deck 107 ft wide.

Who owns US 20 over Anderson Canal?

It is owned by the State Highway Agency.