US Bridges

STC6868;TRAIL Crk over N. Fork Big Lost River

Good

Custer County, Idaho · 20.5 N.E. Sun Valley · Structure no. 000000000033386

Built
2016
9 years old
Condition
Good
inspected July 2022
Type
Tee Beam
Prestressed Concrete
Length
91 ft
1 main span
Daily traffic
300
2023 count
Owner
Local
Other Local Agency

About this bridge

STC6868;TRAIL Crk over N. Fork Big Lost River is a prestressed concrete tee beam carrying STC6868;TRAIL Crk over N. Fork Big Lost River in Custer County, Idaho. It was built in 2016, so it is 9 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 300 vehicles a day, roughly 7% of them trucks, projected to reach 450 by 2042. The structure is 91 ft (27.7 m) long and 32 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesSTC6868;TRAIL Crk
CrossesN. Fork Big Lost River
Location20.5 N.E. Sun Valley
RouteCounty Highway 6868
CountyCuster County
StateIdaho
Coordinates43.93319, -114.11414
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
Deck7 GoodSome minor problems.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation8: Equal to present desirable criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating65 US tons
Inventory rating50 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, precast panels
Main spans1
Design loadHL 93
Structure length91 ft (27.7 m)
Longest span89 ft (27.1 m)
Deck width32 ft (9.8 m)
Roadway width29 ft (8.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic300 (2023)
Projected traffic450 by 2042
Trucks7%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed98.8 mi (159 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 STC6868;TRAIL Crk over N. Fork Big Lost River built?

It was built in 2016, making it 9 years old in 2025.

What condition is STC6868;TRAIL Crk over N. Fork Big Lost River 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 July 2022.

How much traffic does STC6868;TRAIL Crk over N. Fork Big Lost River carry?

About 300 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is STC6868;TRAIL Crk over N. Fork Big Lost River?

The structure is 91 ft (27.7 m) long with a longest span of 89 ft (27.1 m) and a deck 32 ft wide.

Who owns STC6868;TRAIL Crk over N. Fork Big Lost River?

It is owned by the Other Local Agency.