US Bridges

SR 99 over City Streets & Railroad

Good

King County, Washington · 3.3 N JCT SR 509 · Structure no. 0017847A0000000

Built
2011
14 years old
Condition
Good
inspected October 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete Continuous
Length
964 ft
6 main spans
Daily traffic
28,886
2023 count
Owner
State
State Highway Agency

About this bridge

SR 99 over City Streets & Railroad is a prestressed concrete continuous stringer/multi-beam or girder carrying SR 99 over City Streets & Railroad in King County, Washington. It was built in 2011, so it is 14 years old, younger 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 8 out of 9. All primary components (deck, superstructure, substructure, or culvert) are rated 7 or higher. No significant problems were noted.

It carries about 28,886 vehicles a day, roughly 4% of them trucks, projected to reach 47,503 by 2039. The structure is 964 ft (293.8 m) long and 53 ft wide. If it were closed, the detour would be 1.9 mi (3 km).

CarriesSR 99
CrossesCity Streets & Railroad
Location3.3 N JCT SR 509
RouteState Highway 99
Coordinates47.58864, -122.33778
Functional classUrban Principal Arterial - Other Freeway or Expressway

Condition and inspection

Good

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

ComponentRatingMeaning
Deck8 Very GoodNo problems noted.
Superstructure8 Very GoodNo problems noted.
Substructure8 Very GoodNo problems noted.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation8: Equal to present desirable criteria
Deck geometry2: Basically intolerable, requiring high priority of replacement
Approach roadway alignment8: Equal to present desirable criteria
Operating rating47.2 US tons
Inventory rating36.4 US tons

Structure

MaterialPrestressed Concrete Continuous
DeckConcrete, cast-in-place
Main spans6
Design loadHL 93
Structure length964 ft (293.8 m)
Longest span164 ft (50 m)
Deck width53 ft (16.2 m)
Roadway width50 ft (15.2 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic28,886 (2023)
Projected traffic47,503 by 2039
Trucks4%
Lanes on structure4
Traffic directionOne-way traffic
CarriesHighway
CrossesHighway and railroad
Detour if closed1.9 mi (3 km)
TollOn a free road
National Highway SystemYes
Strategic Highway NetworkNon-Interstate STRAHNET route

Ownership and planned work

OwnerState Highway Agency
Maintained byState Highway Agency
Historic statusHistorical significance not determinable at this time
Work proposedRehabilitation because of general structure deterioration or inadequate strength
Estimated improvement cost$23.8 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was SR 99 over City Streets & Railroad built?

It was built in 2011, making it 14 years old in 2025.

What condition is SR 99 over City Streets & Railroad 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 October 2024.

How much traffic does SR 99 over City Streets & Railroad carry?

About 28,886 vehicles per day (2023 count), of which roughly 4% are trucks.

How long is SR 99 over City Streets & Railroad?

The structure is 964 ft (293.8 m) long with a longest span of 164 ft (50 m) and a deck 53 ft wide.

Who owns SR 99 over City Streets & Railroad?

It is owned by the State Highway Agency.