US Bridges

US 20 over Arnold Creek

Fair

Camas County, Idaho · 10.0 W. Fairfield · Structure no. 000000000014990

Built
1961
64 years old
Condition
Fair
inspected July 2023
Type
Frame
Concrete
Length
22 ft
1 main span
Daily traffic
1,900
2023 count
Owner
State
State Highway Agency

About this bridge

US 20 over Arnold Creek is a concrete frame carrying US 20 over Arnold Creek in Camas County, Idaho. It was built in 1961, so it is 64 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 1,900 vehicles a day, roughly 25% of them trucks, projected to reach 2,850 by 2042. The structure is 22 ft (6.7 m) long and 38 ft wide. If it were closed, the detour would be 28 mi (45 km).

Location

Open in Google Maps
CarriesUS 20
CrossesArnold Creek
Location10.0 W. Fairfield
RouteU.S. Route 20
CountyCamas County
StateIdaho
Coordinates43.32936, -114.98594
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 protection6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJuly 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating49.1 US tons
Inventory rating29 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length22 ft (6.7 m)
Longest span22 ft (6.7 m)
Deck width38 ft (11.6 m)
Roadway width36 ft (11.1 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic1,900 (2023)
Projected traffic2,850 by 2042
Trucks25%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed28 mi (45 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$392,000 (2023 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 20 over Arnold Creek built?

It was built in 1961, making it 64 years old in 2025.

What condition is US 20 over Arnold Creek 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 July 2023.

How much traffic does US 20 over Arnold Creek carry?

About 1,900 vehicles per day (2023 count), of which roughly 25% are trucks.

How long is US 20 over Arnold Creek?

The structure is 22 ft (6.7 m) long with a longest span of 22 ft (6.7 m) and a deck 38 ft wide.

Who owns US 20 over Arnold Creek?

It is owned by the State Highway Agency.