US Bridges

Forest Rd. 221-2 over Slate CR

Good

Idaho County, Idaho · 32 Mi. from Grangeville · Structure no. 011701000000046

Built
1976
49 years old
Condition
Good
inspected August 2021
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
92 ft
1 main span
Daily traffic
40
Owner
Federal
U.S. Forest Service

About this bridge

Forest Rd. 221-2 over Slate CR is a prestressed concrete stringer/multi-beam or girder carrying Forest Rd. 221-2 over Slate CR in Idaho County, Idaho. It was built in 1976, so it is 49 years old, older 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 40 vehicles a day, projected to reach 60 by 2045. The structure is 92 ft (28.1 m) long and 29 ft wide. If it were closed, the detour would be 98.2 mi (158 km).

Location

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CarriesForest Rd. 221-2
CrossesSlate CR
Location32 Mi. from Grangeville
RouteFederal Lands Road 221
CountyIdaho County
StateIdaho
Coordinates45.63191, -116.01422
Functional classRural Local

Condition and inspection

Good

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

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionAugust 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation7: Better than present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating40.3 US tons
Inventory rating31.1 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length92 ft (28.1 m)
Longest span90 ft (27.4 m)
Deck width29 ft (8.7 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic40 (—)
Projected traffic60 by 2045
Trucks—
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.2 mi (158 km)
TollOn a free road
National Highway SystemNo

Ownership and planned work

OwnerU.S. Forest Service
Maintained byU.S. Forest Service
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNo navigation control on waterway

Frequently asked questions

When was Forest Rd. 221-2 over Slate CR built?

It was built in 1976, making it 49 years old in 2025.

What condition is Forest Rd. 221-2 over Slate CR 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 August 2021.

How much traffic does Forest Rd. 221-2 over Slate CR carry?

About 40 vehicles per day (latest count).

How long is Forest Rd. 221-2 over Slate CR?

The structure is 92 ft (28.1 m) long with a longest span of 90 ft (27.4 m) and a deck 29 ft wide.

Who owns Forest Rd. 221-2 over Slate CR?

It is owned by the U.S. Forest Service.