US Bridges

US 20 Wbl over Americana BLVD;15th St.

Fair

Ada County, Idaho · In Boise; Front Street · Structure no. 000000000012774

Built
1992
33 years old
Condition
Fair
inspected July 2021
Type
Box Beam or Girders - Multiple
Prestressed Concrete Continuous
Length
549 ft
4 main spans
Daily traffic
32,500
2023 count
Owner
State
State Highway Agency

About this bridge

US 20 Wbl over Americana BLVD;15th St. is a prestressed concrete continuous box beam or girders - multiple carrying US 20 Wbl over Americana BLVD;15th St. in Ada County, Idaho. It was built in 1992, so it is 33 years old, younger 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 32,500 vehicles a day, roughly 4% of them trucks, projected to reach 48,750 by 2042. The structure is 549 ft (167.3 m) long and 56 ft wide.

Location

Open in Google Maps
CarriesUS 20 Wbl
CrossesAmericana BLVD;15th St.
LocationIn Boise; Front Street
RouteU.S. Route 20
CountyAda County
StateIdaho
Coordinates43.6181, -116.213
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionJuly 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry7: Better than present minimum criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54 US tons
Inventory rating35.1 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans4
Design loadHS 25 or greater
Structure length549 ft (167.3 m)
Longest span140 ft (42.7 m)
Deck width56 ft (17.1 m)
Roadway width53 ft (16.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic32,500 (2023)
Projected traffic48,750 by 2042
Trucks4%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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—
NavigationNot applicable (no waterway)

Frequently asked questions

When was US 20 Wbl over Americana BLVD;15th St. built?

It was built in 1992, making it 33 years old in 2025.

What condition is US 20 Wbl over Americana BLVD;15th St. 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 July 2021.

How much traffic does US 20 Wbl over Americana BLVD;15th St. carry?

About 32,500 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is US 20 Wbl over Americana BLVD;15th St.?

The structure is 549 ft (167.3 m) long with a longest span of 140 ft (42.7 m) and a deck 56 ft wide.

Who owns US 20 Wbl over Americana BLVD;15th St.?

It is owned by the State Highway Agency.