Weeknight lane closures on northbound and southbound I-5 in the Des Moines/SeaTac area continue on Monday, Aug. 14, as construction crews working for the Washington State Department of Transportation 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 I-5 in each direction on weeknights from Monday through the morning of Friday, Aug. 25. At least one lane of northbound and southbound I-5 will remain open to traffic.

Lane and ramp closure information:

Monday, Aug. 14 through the morning of Friday, Aug. 18:=

  • 11:59 p.m. – All but one lane of northbound I-5 and one lane of southbound I-5 between South 244th and South 204th streets close to traffic.
  • 4 a.m. – All northbound I-5 lanes reopen to traffic.
  • 6 a.m. – All southbound I-5 lanes reopen to traffic.

Monday, Aug. 21 through the morning of Tuesday, Aug. 22

  • 8:30 p.m. to 5 a.m. – the southbound I-5 on-ramp from South 200th Street is closed.
  • 11:59 p.m. – All but one southbound I-5 lane between South 244th and South 204th streets close to traffic.
  • 6 a.m. – All southbound I-5 lanes reopen to traffic.

Monday, Aug. 21 through the morning of Friday, Aug. 25

  • 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.

Tuesday, Aug. 22 through the morning of Friday, Aug. 25:

  • 9:30 p.m. to 3:30 a.m. – the northbound I-5 off-ramp to eastbound SR 516 is closed.

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.