US Bridges

S 144th ST over I-5 Sound Transit RR

Good

King County, Washington · 0.9 N JCT I-405 · Structure no. 0007618A0000000

Built
1965
60 years old
Condition
Good
inspected October 2024
Type
Stringer/Multi-beam or Girder
Prestressed Concrete
Length
329 ft
4 main spans
Daily traffic
10,356
2020 count
Owner
State
State Highway Agency

About this bridge

S 144th ST over I-5 Sound Transit RR is a prestressed concrete stringer/multi-beam or girder carrying S 144th ST over I-5 Sound Transit RR in King County, Washington. It was built in 1965, so it is 60 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 10,356 vehicles a day, roughly 1% of them trucks, projected to reach 16,003 by 2040. The structure is 329 ft (100.3 m) long and 36 ft wide. If it were closed, the detour would be 3.7 mi (6 km).

Location

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CarriesS 144th ST
CrossesI-5 Sound Transit RR
Location0.9 N JCT I-405
RouteCity Street 0
CountyKing County
StateWashington
Coordinates47.47404, -122.27019
Functional classUrban Collector

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.
Last inspectionOctober 2024
Inspection intervalevery 24 months
Operating statusOpen, no restriction
ScourBridge not over waterway
Structural evaluation4: Meets minimum tolerable limits to be left in place as is
Deck geometry4: Meets minimum tolerable limits to be left in place as is
Approach roadway alignment8: Equal to present desirable criteria
Operating rating24.7 US tons
Inventory rating19 US tons

Structure

Structure typeStringer/Multi-beam or Girder
MaterialPrestressed Concrete
DeckConcrete, cast-in-place
Main spans4
Design loadHS 20
Structure length329 ft (100.3 m)
Longest span113 ft (34.4 m)
Deck width36 ft (10.9 m)
Roadway width28 ft (8.5 m)
Vertical clearance over deckUnrestricted

Traffic and service

Average daily traffic10,356 (2020)
Projected traffic16,003 by 2040
Trucks1%
Lanes on structure2
Traffic directionTwo-way traffic
CarriesHighway and pedestrian
CrossesHighway
Detour if closed3.7 mi (6 km)
TollOn a free road
National Highway SystemNo

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$4.7 million (2022 estimate)
NavigationNot applicable (no waterway)

Frequently asked questions

When was S 144th ST over I-5 Sound Transit RR built?

It was built in 1965, making it 60 years old in 2025.

What condition is S 144th ST over I-5 Sound Transit RR 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 S 144th ST over I-5 Sound Transit RR carry?

About 10,356 vehicles per day (2020 count), of which roughly 1% are trucks.

How long is S 144th ST over I-5 Sound Transit RR?

The structure is 329 ft (100.3 m) long with a longest span of 113 ft (34.4 m) and a deck 36 ft wide.

Who owns S 144th ST over I-5 Sound Transit RR?

It is owned by the State Highway Agency.