Weeknight lane closures on northbound I-5 in the SeaTac/Des Moines area continue through this Friday, Sept. 8, 2023, as construction crews working for the Washington State Department of Transportation (WSDOT) build new bridges as part of the State Route 509 Completion Project.

The overnight lane closures are necessary for the construction of bridge decks for the new South 216th Street bridge and northbound flyover ramp to the SR 509 expressway.

During bridge deck construction, crews will close up to four lanes of northbound I-5 through the morning of Friday, Sept. 8. At least one lane will remain open to traffic.

Lane and ramp closure information

Tuesday, Sept. 5 through the morning of Friday, Sept. 8:

  • 7 p.m. – The northbound I-5 off-ramp to South 200th Street is closed.
  • 11:59 p.m. – All but one northbound I-5 lane between South 244th and South 204th streets close to traffic.
  • 3:30 a.m. – All northbound I-5 lanes reopen to traffic.
  • 4:30 a.m. – The northbound I-5 off-ramp to South 200th Street reopens.

Drivers should plan to slow down and drive safely through the active construction zone.

Know before you go

Before heading out the door, travelers can find the latest information on the WSDOT app, the real-time travel map, or by subscribing to WSDOT’s email and text alerts.