US Bridges

SR 99 over Cloverdale ST

Fair

King County, Washington · 2.5 N JCT SR 599 · Structure no. 0006046B0000000

Built
1959
66 years old
Condition
Fair
inspected March 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
86 ft
1 main span
Daily traffic
13,545
2023 count
Owner
State
State Highway Agency

About this bridge

SR 99 over Cloverdale ST is a prestressed concrete stringer/multi-beam or girder carrying SR 99 over Cloverdale ST in King County, Washington. It was built in 1959, so it is 66 years old, older 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 13,545 vehicles a day, roughly 11% of them trucks, projected to reach 22,258 by 2039. The structure is 86 ft (26.2 m) long and 120 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

Location

Open in Google Maps
CarriesSR 99
CrossesCloverdale ST
Location2.5 N JCT SR 599
RouteState Highway 99
CountyKing County
StateWashington
Coordinates47.52638, -122.32421
Functional classUrban Principal Arterial - Other Freeway or Expressway

Condition and inspection

Fair

The lowest-rated primary component is rated 5 or 6. Minor deterioration is present but the structure is sound.

ComponentRatingMeaning
Deck7 GoodSome minor problems.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure7 GoodSome minor problems.
Last inspectionMarch 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry9: Superior to present desirable criteria
Approach roadway alignment8: Equal to present desirable criteria
Operating rating84 US tons
Inventory rating50 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans1
Design loadHS 20 + Mod
Structure length86 ft (26.2 m)
Longest span84 ft (25.6 m)
Deck width120 ft (36.6 m)
Roadway width116 ft (35.4 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic13,545 (2023)
Projected traffic22,258 by 2039
Trucks11%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway
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 statusNot eligible for the National Register of Historic Places
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$4.8 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 99 over Cloverdale ST built?

It was built in 1959, making it 66 years old in 2025.

What condition is SR 99 over Cloverdale ST 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 March 2024.

How much traffic does SR 99 over Cloverdale ST carry?

About 13,545 vehicles per day (2023 count), of which roughly 11% are trucks.

How long is SR 99 over Cloverdale ST?

The structure is 86 ft (26.2 m) long with a longest span of 84 ft (25.6 m) and a deck 120 ft wide.

Who owns SR 99 over Cloverdale ST?

It is owned by the State Highway Agency.