SR 509

Route ID
509

A celebration of connections marks the final stage of SR 509 construction in South King County

SR 509 Completion Project will connect the 50-year-old highway to I-5

SEATAC – Community, industry and elected leaders joined together in SeaTac on Wednesday, Sept. 25, to celebrate the beginning of construction on the final stage of the State Route 509 Completion Project in south King County. 

Contract to finish the final stage of the SR 509 Completion project near SeaTac awarded

SEATAC – The Puget Sound Gateway Program is celebrating a significant milestone on the road to completing State Route 509 in south King County. On Monday, Dec. 4 the Washington State Department of Transportation awarded the contract to Guy F. Atkinson Construction to complete the final stage of the highway.

Building new bridges over I-5 in SeaTac/Des Moines requires significant traffic shift starting June 26

Nighttime drivers will use cross-over lane while girders are set for new South 216th Street bridge and new flyover ramp

SEATAC – Lifting and carefully placing long pieces of concrete weighing roughly 200,000 pounds is no easy feat, but that is about to happen on Interstate 5 in the SeaTac/Des Moines area.

Update: Overnight ramp closures, detours at I-5/SR 18 interchange May 3-5 and May 2 on SR 509

UPDATE: Work rescheduled for week of May 1

FEDERAL WAY – Evening travelers in south King County should add additional time or adjust routes the week of May 1 for ramp and/or lane closures in two locations, including State Route 509 and the Interstate 5/State Route 18 interchange in Federal Way.

Online open house offers first glimpse of future State Route 509 expressway using 3D model

SEATAC – Members of the public are invited to an online open house to learn more about current designs and planning for the final stage (Stage 2) of the State Route 509 Completion Project in south King County, which includes construction of a new four-lane, three-mile SR 509 expressway. The online open house will also include the release of a 3D video tour of the full project, modeled from current designs.

Slow down on ice and snow.

It's easier to skid or lose control traveling at higher speeds. Give yourself more time to stop.

Carry chains, practice installing them.

Winter conditions could mean chains are required on your route. Practice putting them on your vehicle ahead of time.

Pack your winter car kit.

Carry extra supplies like warm clothing, ice scraper and brush, jumper cables and other emergency items.