US Bridges

SR 99 over N 63rd ST

Fair

King County, Washington · 9.8 N JCT SR 509 · Structure no. 0001673A0000000

Built
1932
93 years old
Condition
Fair
inspected June 2023
Type
Slab
Concrete Continuous
Length
73 ft
2 main spans
Daily traffic
33,359
2023 count
Owner
State
State Highway Agency

About this bridge

SR 99 over N 63rd ST is a concrete continuous slab carrying SR 99 over N 63rd ST in King County, Washington. It was built in 1932, so it is 93 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 33,359 vehicles a day, roughly 3% of them trucks, projected to reach 47,791 by 2039. The structure is 73 ft (22.3 m) long and 79 ft wide. If it were closed, the detour would be 1.2 mi (2 km).

Location

Open in Google Maps
CarriesSR 99
CrossesN 63rd ST
Location9.8 N JCT SR 509
RouteState Highway 99
CountyKing County
StateWashington
Coordinates47.67416, -122.34722
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
Deck6 SatisfactoryStructural elements show some minor deterioration.
Superstructure6 SatisfactoryStructural elements show some minor deterioration.
Substructure6 SatisfactoryStructural elements show some minor deterioration.
Last inspectionJune 2023
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation6: Equal to present minimum criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating54 US tons
Inventory rating29 US tons

Structure

Structure typeSlab
MaterialConcrete Continuous
DeckConcrete, cast-in-place
Main spans2
Design loadUnknown
Structure length73 ft (22.3 m)
Longest span51 ft (15.5 m)
Deck width79 ft (24.1 m)
Roadway width61 ft (18.6 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic33,359 (2023)
Projected traffic47,791 by 2039
Trucks3%
Lanes on structure6
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed1.2 mi (2 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$2.2 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 99 over N 63rd ST built?

It was built in 1932, making it 93 years old in 2025.

What condition is SR 99 over N 63rd 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 June 2023.

How much traffic does SR 99 over N 63rd ST carry?

About 33,359 vehicles per day (2023 count), of which roughly 3% are trucks.

How long is SR 99 over N 63rd ST?

The structure is 73 ft (22.3 m) long with a longest span of 51 ft (15.5 m) and a deck 79 ft wide.

Who owns SR 99 over N 63rd ST?

It is owned by the State Highway Agency.