US Bridges

US 20 ;i 84B over Ridenbaugh Canal

Fair

Ada County, Idaho · In Boise;broadway Ave · Structure no. 000000000012275

Built
1970
55 years old
Condition
Fair
inspected November 2022
Type
Frame
Concrete
Length
45 ft
1 main span
Daily traffic
26,000
2023 count
Owner
State
State Highway Agency

About this bridge

US 20 ;i 84B over Ridenbaugh Canal is a concrete frame carrying US 20 ;i 84B over Ridenbaugh Canal in Ada County, Idaho. It was built in 1970, so it is 55 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 26,000 vehicles a day, roughly 7% of them trucks, projected to reach 39,000 by 2042. The structure is 45 ft (13.7 m) long and 122 ft wide.

Location

Open in Google Maps
CarriesUS 20 ;i 84B
CrossesRidenbaugh Canal
LocationIn Boise;broadway Ave
RouteU.S. Route 20
CountyAda County
StateIdaho
Coordinates43.57542, -116.19358
Functional classUrban Other Principal Arterial

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 inspectionNovember 2022
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour above top of footing
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating82 US tons
Inventory rating49.1 US tons

Structure

Structure typeFrame
MaterialConcrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20
Structure length45 ft (13.7 m)
Longest span45 ft (13.7 m)
Deck width122 ft (37.2 m)
Roadway width121 ft (37 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic26,000 (2023)
Projected traffic39,000 by 2042
Trucks7%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed—
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—
NavigationNo navigation control on waterway

Frequently asked questions

When was US 20 ;i 84B over Ridenbaugh Canal built?

It was built in 1970, making it 55 years old in 2025.

What condition is US 20 ;i 84B over Ridenbaugh 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 November 2022.

How much traffic does US 20 ;i 84B over Ridenbaugh Canal carry?

About 26,000 vehicles per day (2023 count), of which roughly 7% are trucks.

How long is US 20 ;i 84B over Ridenbaugh Canal?

The structure is 45 ft (13.7 m) long with a longest span of 45 ft (13.7 m) and a deck 122 ft wide.

Who owns US 20 ;i 84B over Ridenbaugh Canal?

It is owned by the State Highway Agency.