US Bridges

Stc 4710;ROCKY Cyn over Rock Creek

Good

Idaho County, Idaho · 9.4 S. 2.3 W. Cottonwood · Structure no. 000000000029376

Built
1998
27 years old
Condition
Good
inspected June 2022
Type
Tee Beam
Prestressed Concrete
Length
70 ft
1 main span
Daily traffic
170
2023 count
Owner
Local
Other Local Agency

About this bridge

Stc 4710;ROCKY Cyn over Rock Creek is a prestressed concrete tee beam carrying Stc 4710;ROCKY Cyn over Rock Creek in Idaho County, Idaho. It was built in 1998, so it is 27 years old, younger than the Idaho average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 170 vehicles a day, roughly 6% of them trucks, projected to reach 255 by 2042. The structure is 70 ft (21.3 m) long and 30 ft wide. If it were closed, the detour would be 29.8 mi (48 km).

Location

Open in Google Maps
CarriesStc 4710;ROCKY Cyn
CrossesRock Creek
Location9.4 S. 2.3 W. Cottonwood
RouteCounty Highway 4710
CountyIdaho County
StateIdaho
Coordinates45.9111, -116.39764
Functional classRural Major Collector

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure7 GoodSome minor problems.
Channel and channel protection9 ExcellentNo problems noted.
Last inspectionJune 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation7: Better than 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 rating81 US tons
Inventory rating44 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length70 ft (21.3 m)
Longest span68 ft (20.7 m)
Deck width30 ft (9.1 m)
Roadway width27 ft (8.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic170 (2023)
Projected traffic255 by 2042
Trucks6%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed29.8 mi (48 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerOther Local Agency
Maintained byOther Local 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 Stc 4710;ROCKY Cyn over Rock Creek built?

It was built in 1998, making it 27 years old in 2025.

What condition is Stc 4710;ROCKY Cyn over Rock Creek in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in June 2022.

How much traffic does Stc 4710;ROCKY Cyn over Rock Creek carry?

About 170 vehicles per day (2023 count), of which roughly 6% are trucks.

How long is Stc 4710;ROCKY Cyn over Rock Creek?

The structure is 70 ft (21.3 m) long with a longest span of 68 ft (20.7 m) and a deck 30 ft wide.

Who owns Stc 4710;ROCKY Cyn over Rock Creek?

It is owned by the Other Local Agency.