US Bridges

SH 21 over Elk Creek

Fair

Custer County, Idaho · 7.2 W. Stanley · Structure no. 000000000036120

Built
2022
3 years old
Condition
Fair
inspected July 2024
Type
Frame
Concrete
Length
28 ft
1 main span
Daily traffic
620
2023 count
Owner
State
State Highway Agency

About this bridge

SH 21 over Elk Creek is a concrete frame carrying SH 21 over Elk Creek in Custer County, Idaho. It was built in 2022, so it is 3 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 620 vehicles a day, roughly 22% of them trucks, projected to reach 930 by 2042. The structure is 28 ft (8.5 m) long and 28 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSH 21
CrossesElk Creek
Location7.2 W. Stanley
RouteState Highway 21
CountyCuster County
StateIdaho
Coordinates44.28782, -115.03263
Functional classRural 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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 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 adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating69.3 US tons
Inventory rating53.6 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, precast panels
Main spans1
Design loadHL 93
Structure length28 ft (8.5 m)
Longest span28 ft (8.5 m)
Deck width28 ft (8.5 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic620 (2023)
Projected traffic930 by 2042
Trucks22%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed1.9 mi (3 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 SH 21 over Elk Creek built?

It was built in 2022, making it 3 years old in 2025.

What condition is SH 21 over Elk 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 2024.

How much traffic does SH 21 over Elk Creek carry?

About 620 vehicles per day (2023 count), of which roughly 22% are trucks.

How long is SH 21 over Elk Creek?

The structure is 28 ft (8.5 m) long with a longest span of 28 ft (8.5 m) and a deck 28 ft wide.

Who owns SH 21 over Elk Creek?

It is owned by the State Highway Agency.