US Bridges

I-90 over 424th Ave SE

Fair

King County, Washington · 1.5 E JCT SR 202 · Structure no. 0010124B0000000

Built
1976
49 years old
Condition
Fair
inspected June 2024
Type
Slab
Concrete Continuous
Length
120 ft
3 main spans
Daily traffic
24,954
2023 count
Owner
State
State Highway Agency

About this bridge

I-90 over 424th Ave SE is a concrete continuous slab carrying I-90 over 424th Ave SE in King County, Washington. It was built in 1976, so it is 49 years old, younger than the Washington average of 49.8 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 24,954 vehicles a day, roughly 18% of them trucks, projected to reach 34,071 by 2039. The structure is 120 ft (36.6 m) long and 55 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

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CarriesI-90
Crosses424th Ave SE
Location1.5 E JCT SR 202
RouteInterstate 90
CountyKing County
StateWashington
Coordinates47.47361, -121.77481
Functional classRural Principal Arterial - Interstate

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.
Superstructure7 GoodSome minor problems.
Substructure7 GoodSome minor problems.
Last inspectionJune 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation7: Better than present minimum criteria
Deck geometry5: Somewhat better than minimum adequacy to tolerate being left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating48.9 US tons
Inventory rating37.8 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans3
Design loadHS 20 + Mod
Structure length120 ft (36.6 m)
Longest span52 ft (15.8 m)
Deck width55 ft (16.8 m)
Roadway width52 ft (15.8 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic24,954 (2023)
Projected traffic34,071 by 2039
Trucks18%
Lanes on structure3
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
Detour if closed1.2 mi (2 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkInterstate STRAHNET route

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$3.1 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was I-90 over 424th Ave SE built?

It was built in 1976, making it 49 years old in 2025.

What condition is I-90 over 424th Ave SE 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 June 2024.

How much traffic does I-90 over 424th Ave SE carry?

About 24,954 vehicles per day (2023 count), of which roughly 18% are trucks.

How long is I-90 over 424th Ave SE?

The structure is 120 ft (36.6 m) long with a longest span of 52 ft (15.8 m) and a deck 55 ft wide.

Who owns I-90 over 424th Ave SE?

It is owned by the State Highway Agency.