US Bridges

US 12 over US 12;SNAKE River

Fair

Nez Perce County, Idaho · In Lewiston at State Line · Structure no. 000000000010360

Built
1939
86 years old
Condition
Fair
inspected September 2023
Type
Movable - Lift
Steel
Length
1,424 ft
3 main spans
Daily traffic
21,000
2023 count
Owner
State
State Highway Agency

About this bridge

US 12 over US 12;SNAKE River is a steel movable - lift carrying US 12 over US 12;SNAKE River in Nez Perce County, Idaho. It was built in 1939, so it is 86 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 5 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 21,000 vehicles a day, roughly 2% of them trucks, projected to reach 31,500 by 2042. The structure is 1,424 ft (434 m) long and 48 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesUS 12
CrossesUS 12;SNAKE River
LocationIn Lewiston at State Line
RouteU.S. Route 12
CountyNez Perce County
StateIdaho
Coordinates46.42042, -117.0335
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.
Superstructure5 FairAll primary structural elements are sound but may have minor section loss, cracking, spalling or scour.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionSeptember 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourScour critical; foundations unstable for calculated scour conditions
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry2: Basically intolerable, requiring high priority of replacement
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment3: Basically intolerable, requiring high priority of corrective action
Operating rating35.1 US tons
Inventory rating21.1 US tons

Structure

Structure typeMovable - Lift
MaterialSteel
DeckConcrete, cast-in-place
Main spans3 (+14 approach)
Design loadH 15
Structure length1,424 ft (434 m)
Longest span200 ft (61 m)
Deck width48 ft (14.7 m)
Roadway width40 ft (12.2 m)
Vertical clearance over deck15 ft (4.4 m)

Traffic and service

Average daily traffic21,000 (2023)
Projected traffic31,500 by 2042
Trucks2%
Lanes on structure4
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway and waterway
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusPossibly eligible for the National Register; requires further investigation
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$23.9 million
NavigationNavigation control on waterway (bridge permit required)

Frequently asked questions

When was US 12 over US 12;SNAKE River built?

It was built in 1939, making it 86 years old in 2025.

What condition is US 12 over US 12;SNAKE 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 September 2023.

How much traffic does US 12 over US 12;SNAKE River carry?

About 21,000 vehicles per day (2023 count), of which roughly 2% are trucks.

How long is US 12 over US 12;SNAKE River?

The structure is 1,424 ft (434 m) long with a longest span of 200 ft (61 m) and a deck 48 ft wide.

Who owns US 12 over US 12;SNAKE River?

It is owned by the State Highway Agency.