US Bridges

US 12 over Cowlitz R Overflow

Good

Lewis County, Washington · 8.5 E JCT SR 131 · Structure no. 0005889B0000000

Built
1958
67 years old
Condition
Good
inspected February 2023
Type
Slab
Concrete Continuous
Length
130 ft
5 main spans
Daily traffic
2,712
2023 count
Owner
State
State Highway Agency

About this bridge

US 12 over Cowlitz R Overflow is a concrete continuous slab carrying US 12 over Cowlitz R Overflow in Lewis County, Washington. It was built in 1958, so it is 67 years old, older than the Washington average of 49.8 years.

The most recent inspection reported to the Federal Highway Administration rates it in good condition with a lowest component rating of 7 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 2,712 vehicles a day, roughly 19% of them trucks, projected to reach 4,281 by 2039. The structure is 130 ft (39.6 m) long and 31 ft wide. If it were closed, the detour would be 18 mi (29 km).

CarriesUS 12
CrossesCowlitz R Overflow
Location8.5 E JCT SR 131
RouteU.S. Route 12
Coordinates46.53373, -121.77939
Functional classRural Principal Arterial - Other

Condition and inspection

Good

All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Channel and channel protection8 Very GoodNo problems noted.
Last inspectionFebruary 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourFoundations stable; scour within limits of footing or piles
Structural evaluation6: Equal to present minimum criteria
Deck geometry3: Basically intolerable, requiring high priority of corrective action
Waterway adequacy8: Equal to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating34.3 US tons
Inventory rating26.5 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans5
Design loadHS 20
Structure length130 ft (39.6 m)
Longest span28 ft (8.5 m)
Deck width31 ft (9.4 m)
Roadway width26 ft (7.9 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic2,712 (2023)
Projected traffic4,281 by 2039
Trucks19%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway
CrossesRelief for waterway
Detour if closed18 mi (29 km)
TollOn a free road
National Highway SystemYes

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$2.5 million (2022 estimate)
NavigationNo navigation control on waterway

Frequently asked questions

When was US 12 over Cowlitz R Overflow built?

It was built in 1958, making it 67 years old in 2025.

What condition is US 12 over Cowlitz R Overflow in?

The National Bridge Inventory rates it in good condition. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted. The last reported inspection was in February 2023.

How much traffic does US 12 over Cowlitz R Overflow carry?

About 2,712 vehicles per day (2023 count), of which roughly 19% are trucks.

How long is US 12 over Cowlitz R Overflow?

The structure is 130 ft (39.6 m) long with a longest span of 28 ft (8.5 m) and a deck 31 ft wide.

Who owns US 12 over Cowlitz R Overflow?

It is owned by the State Highway Agency.