US Bridges

E 421 N over Lewisville Canal

PoorPosted for load

Jefferson County, Idaho · 1.1 N. 2.4 E. Rigby · Structure no. 000000000036100

Built
1960
65 years old
Condition
Poor
inspected November 2024
Type
Tee Beam
Concrete
Length
39 ft
1 main span
Daily traffic
50
2023 count
Owner
County
County Highway Agency

About this bridge

E 421 N over Lewisville Canal is a concrete tee beam carrying E 421 N over Lewisville Canal in Jefferson County, Idaho. It was built in 1960, so it is 65 years old, older than the Idaho average of 45.3 years.

The most recent inspection reported to the Federal Highway Administration rates it in poor condition with a lowest component rating of 4 out of 9. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. Its operating status is: posted for load restriction.

It carries about 50 vehicles a day, projected to reach 75 by 2039. The structure is 39 ft (11.9 m) long and 28 ft wide. If it were closed, the detour would be 98.8 mi (159 km).

Location

Open in Google Maps
CarriesE 421 N
CrossesLewisville Canal
Location1.1 N. 2.4 E. Rigby
RouteCounty Highway 0
CountyJefferson County
StateIdaho
Coordinates43.68889, -111.86808
Functional classRural Local

Condition and inspection

Poor

The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions.

ComponentRatingMeaning
Deck5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Superstructure4 PoorAdvanced section loss, deterioration, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 2024
Inspection intervalevery 12 months
Operating statusPosted for load restriction
ScourFoundations stable; scour above top of footing
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 alignment5: Somewhat better than minimum adequacy to tolerate being left in place as is
Operating rating20 US tons
Inventory rating12 US tons

Structure

Structure typeTee Beam
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length39 ft (11.9 m)
Longest span35 ft (10.7 m)
Deck width28 ft (8.6 m)
Roadway width24 ft (7.3 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic50 (2023)
Projected traffic75 by 2039
Trucks0%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed98.8 mi (159 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 proposedReplacement because of substandard load-carrying capacity or roadway geometry
Estimated improvement cost$528,000 (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was E 421 N over Lewisville Canal built?

It was built in 1960, making it 65 years old in 2025.

What condition is E 421 N over Lewisville Canal in?

The National Bridge Inventory rates it in poor condition. The lowest-rated primary component is rated 4 or below, indicating advanced deterioration. Poor does not mean unsafe; such bridges are inspected more often and may carry load restrictions. The last reported inspection was in November 2024.

How much traffic does E 421 N over Lewisville Canal carry?

About 50 vehicles per day (2023 count).

How long is E 421 N over Lewisville Canal?

The structure is 39 ft (11.9 m) long with a longest span of 35 ft (10.7 m) and a deck 28 ft wide.

Who owns E 421 N over Lewisville Canal?

It is owned by the County Highway Agency.