US Bridges

US 20B over US 20 Nb-Sb;s.Rigby Ic

Fair

Jefferson County, Idaho · 0.5 S. Rigby · Structure no. 000000000012710

Built
1976
49 years old
Condition
Fair
inspected May 2022
Type
Box Beam or Girders - Single or Spread
Concrete Continuous
Length
302 ft
4 main spans
Daily traffic
3,000
2023 count
Owner
State
State Highway Agency

About this bridge

US 20B over US 20 Nb-Sb;s.Rigby Ic is a concrete continuous box beam or girders - single or spread carrying US 20B over US 20 Nb-Sb;s.Rigby Ic in Jefferson 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 3,000 vehicles a day, projected to reach 4,500 by 2042. The structure is 302 ft (92 m) long and 29 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesUS 20B
CrossesUS 20 Nb-Sb;s.Rigby Ic
Location0.5 S. Rigby
RouteU.S. Route 20
CountyJefferson County
StateIdaho
Coordinates43.66089, -111.91889
Functional classRural Principal Arterial - Other

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.
Last inspectionMay 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Approach roadway alignment6: Equal to present minimum criteria
Operating rating48 US tons
Inventory rating34 US tons

Structure

Structure typeBox Beam or Girders - Single or Spread
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length302 ft (92 m)
Longest span95 ft (29 m)
Deck width29 ft (8.7 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic3,000 (2023)
Projected traffic4,500 by 2042
Trucks0%
Lanes on structure1
Traffic directionOne-way traffic
CarriesOverpass structure at an interchange
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedNone recorded
Estimated improvement cost—
NavigationNot applicable (no waterway)

Frequently asked questions

When was US 20B over US 20 Nb-Sb;s.Rigby Ic built?

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

What condition is US 20B over US 20 Nb-Sb;s.Rigby Ic 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 May 2022.

How much traffic does US 20B over US 20 Nb-Sb;s.Rigby Ic carry?

About 3,000 vehicles per day (2023 count).

How long is US 20B over US 20 Nb-Sb;s.Rigby Ic?

The structure is 302 ft (92 m) long with a longest span of 95 ft (29 m) and a deck 29 ft wide.

Who owns US 20B over US 20 Nb-Sb;s.Rigby Ic?

It is owned by the State Highway Agency.