US Bridges

County Line Road over Noble Canal

Fair

Gem County, Idaho · 0.6 N. 3.2 W. Letha · Structure no. 000000000028095

Built
1966
59 years old
Condition
Fair
inspected March 2024
Type
Tee Beam
Prestressed Concrete
Length
25 ft
1 main span
Daily traffic
170
2023 count
Owner
County
County Highway Agency

About this bridge

County Line Road over Noble Canal is a prestressed concrete tee beam carrying County Line Road over Noble Canal in Gem County, Idaho. It was built in 1966, so it is 59 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 170 vehicles a day, roughly 10% of them trucks, projected to reach 255 by 2039. The structure is 25 ft (7.6 m) long and 28 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesCounty Line Road
CrossesNoble Canal
Location0.6 N. 3.2 W. Letha
RouteCounty Highway 0
CountyGem County
StateIdaho
Coordinates43.90278, -116.71233
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.
Superstructure7 GoodSome minor problems.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionMarch 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 rating68 US tons
Inventory rating48.6 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length25 ft (7.6 m)
Longest span23 ft (7 m)
Deck width28 ft (8.6 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic170 (2023)
Projected traffic255 by 2039
Trucks10%
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

OwnerCounty Highway Agency
Maintained byCounty 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 County Line Road over Noble Canal built?

It was built in 1966, making it 59 years old in 2025.

What condition is County Line Road over Noble Canal 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 March 2024.

How much traffic does County Line Road over Noble Canal carry?

About 170 vehicles per day (2023 count), of which roughly 10% are trucks.

How long is County Line Road over Noble Canal?

The structure is 25 ft (7.6 m) long with a longest span of 23 ft (7 m) and a deck 28 ft wide.

Who owns County Line Road over Noble Canal?

It is owned by the County Highway Agency.