US Bridges

Jernberg Road over Jefferson Canal

Fair

Jefferson County, Idaho · 5.66 N Mud Lake · Structure no. 000000000036170

Built
1978
47 years old
Condition
Fair
inspected March 2024
Type
Tee Beam
Prestressed Concrete
Length
32 ft
1 main span
Daily traffic
20
2023 count
Owner
County
County Highway Agency

About this bridge

Jernberg Road over Jefferson Canal is a prestressed concrete tee beam carrying Jernberg Road over Jefferson Canal in Jefferson County, Idaho. It was built in 1978, so it is 47 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 20 vehicles a day, roughly 2% of them trucks, projected to reach 30 by 2040. The structure is 32 ft (9.8 m) long and 28 ft wide. If it were closed, the detour would be 5 mi (8 km).

Location

Open in Google Maps
CarriesJernberg Road
CrossesJefferson Canal
Location5.66 N Mud Lake
RouteCounty Highway 0
CountyJefferson County
StateIdaho
Coordinates43.92286, -112.49114
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Channel and channel protection7 GoodSome minor problems.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating38 US tons
Inventory rating23 US tons

Structure

Structure typeTee Beam
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length32 ft (9.8 m)
Longest span31 ft (9.4 m)
Deck width28 ft (8.5 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic20 (2023)
Projected traffic30 by 2040
Trucks2%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed5 mi (8 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 Jernberg Road over Jefferson Canal built?

It was built in 1978, making it 47 years old in 2025.

What condition is Jernberg Road over Jefferson 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 Jernberg Road over Jefferson Canal carry?

About 20 vehicles per day (2023 count), of which roughly 2% are trucks.

How long is Jernberg Road over Jefferson Canal?

The structure is 32 ft (9.8 m) long with a longest span of 31 ft (9.4 m) and a deck 28 ft wide.

Who owns Jernberg Road over Jefferson Canal?

It is owned by the County Highway Agency.