US Bridges

SH 6 over Palouse River

Fair

Latah County, Idaho · 3.7 N. Harvard · Structure no. 000000000018831

Built
1991
34 years old
Condition
Fair
inspected July 2021
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
79 ft
1 main span
Daily traffic
910
2023 count
Owner
State
State Highway Agency

About this bridge

SH 6 over Palouse River is a prestressed concrete stringer/multi-beam or girder carrying SH 6 over Palouse River in Latah County, Idaho. It was built in 1991, so it is 34 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 910 vehicles a day, roughly 34% of them trucks, projected to reach 1,365 by 2042. The structure is 79 ft (24.1 m) long and 36 ft wide. If it were closed, the detour would be 3.1 mi (5 km).

Location

Open in Google Maps
CarriesSH 6
CrossesPalouse River
Location3.7 N. Harvard
RouteState Highway 6
CountyLatah County
StateIdaho
Coordinates46.94878, -116.67339
Functional classRural Major Collector

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.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionJuly 2021
Inspection intervalevery 48 months
Operating statusOpen, no restriction
ScourFoundations on dry land well above flood water elevations
Structural evaluation8: Equal to present desirable criteria
Deck geometry6: Equal to present minimum criteria
Waterway adequacy9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating110.1 US tons
Inventory rating56 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 25 or greater
Structure length79 ft (24.1 m)
Longest span77 ft (23.5 m)
Deck width36 ft (10.9 m)
Roadway width32 ft (9.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic910 (2023)
Projected traffic1,365 by 2042
Trucks34%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesWaterway
Detour if closed3.1 mi (5 km)
TollOn a free road
National Highway SystemNo

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 SH 6 over Palouse River built?

It was built in 1991, making it 34 years old in 2025.

What condition is SH 6 over Palouse 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 July 2021.

How much traffic does SH 6 over Palouse River carry?

About 910 vehicles per day (2023 count), of which roughly 34% are trucks.

How long is SH 6 over Palouse River?

The structure is 79 ft (24.1 m) long with a longest span of 77 ft (23.5 m) and a deck 36 ft wide.

Who owns SH 6 over Palouse River?

It is owned by the State Highway Agency.