US Bridges

Sixbit Road over S. Fk Salmon River

Fair

Valley County, Idaho · 5 MI N. of Warm Lake · Structure no. 040204000001091

Built
1976
49 years old
Condition
Fair
inspected August 2023
Type
Stringer/Multi-beam or Girder
Steel Continuous
Length
97 ft
2 main spans
Daily traffic
15
1990 count
Owner
Federal
U.S. Forest Service

About this bridge

Sixbit Road over S. Fk Salmon River is a steel continuous stringer/multi-beam or girder carrying Sixbit Road over S. Fk Salmon River in Valley 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 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 15 vehicles a day, projected to reach 22 by 2045. The structure is 97 ft (29.6 m) long and 15 ft wide. If it were closed, the detour would be 18.6 mi (30 km).

Location

Open in Google Maps
CarriesSixbit Road
CrossesS. Fk Salmon River
Location5 MI N. of Warm Lake
RouteFederal Lands Road 493
CountyValley County
StateIdaho
Coordinates44.72019, -115.69362
Functional classRural Local

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
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 inspectionAugust 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; action required to protect exposed foundations
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment6: Equal to present minimum criteria
Operating rating22.2 US tons
Inventory rating17.2 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialSteel Continuous
DeckWood or timber
Main spans2
Design loadHS 20
Structure length97 ft (29.6 m)
Longest span48 ft (14.6 m)
Deck width15 ft (4.7 m)
Roadway width14 ft (4.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15 (1990)
Projected traffic22 by 2045
Trucks—
Lanes on structure1
Traffic directionOne-lane bridge for two-way traffic
CarriesHighway
CrossesWaterway
Detour if closed18.6 mi (30 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 Sixbit Road over S. Fk Salmon River built?

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

What condition is Sixbit Road over S. Fk Salmon River 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 August 2023.

How much traffic does Sixbit Road over S. Fk Salmon River carry?

About 15 vehicles per day (1990 count).

How long is Sixbit Road over S. Fk Salmon River?

The structure is 97 ft (29.6 m) long with a longest span of 48 ft (14.6 m) and a deck 15 ft wide.

Who owns Sixbit Road over S. Fk Salmon River?

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