US Bridges

Nhs 7183;9th ST over Boise River

Fair

Ada County, Idaho · In Boise;s. 9th Street · Structure no. 000000000021655

Built
1987
38 years old
Condition
Fair
inspected November 2021
Type
Box Beam or Girders - Multiple
Steel Continuous
Length
311 ft
2 main spans
Daily traffic
15,500
2023 count
Owner
County
County Highway Agency

About this bridge

Nhs 7183;9th ST over Boise River is a steel continuous box beam or girders - multiple carrying Nhs 7183;9th ST over Boise River in Ada County, Idaho. It was built in 1987, so it is 38 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 15,500 vehicles a day, roughly 2% of them trucks, projected to reach 23,250 by 2042. The structure is 311 ft (94.8 m) long and 64 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesNhs 7183;9th ST
CrossesBoise River
LocationIn Boise;s. 9th Street
RouteCity Street 7183
CountyAda County
StateIdaho
Coordinates43.609, -116.20958
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.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionNovember 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating61 US tons
Inventory rating37 US tons

Structure

Structure typeBox Beam or Girders - Multiple
MaterialSteel Continuous
DeckConcrete, cast-in-place
Main spans2 (+1 approach)
Design loadHS 20
Structure length311 ft (94.8 m)
Longest span145 ft (44.2 m)
Deck width64 ft (19.6 m)
Roadway width51 ft (15.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic15,500 (2023)
Projected traffic23,250 by 2042
Trucks2%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway and pedestrian
CrossesWaterway
Detour if closed1.2 mi (2 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 proposedWidening with deck rehabilitation or replacement
Estimated improvement cost$1.4 million (2017 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was Nhs 7183;9th ST over Boise River built?

It was built in 1987, making it 38 years old in 2025.

What condition is Nhs 7183;9th ST over Boise River 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 2021.

How much traffic does Nhs 7183;9th ST over Boise River carry?

About 15,500 vehicles per day (2023 count), of which roughly 2% are trucks.

How long is Nhs 7183;9th ST over Boise River?

The structure is 311 ft (94.8 m) long with a longest span of 145 ft (44.2 m) and a deck 64 ft wide.

Who owns Nhs 7183;9th ST over Boise River?

It is owned by the County Highway Agency.