SEATTLE — Editor's note: the above video was originally published in August 2018 about the technology that makes light rail traveling on the floating bridge possible.

Those traveling from Mercer Island or Bellevue to Seattle on westbound I-90 should plan for delays and alternate routes Friday, Oct 4. 

Washington State Department of Transportation crews will be inspecting the safety systems inside the Mount Baker Tunnel. 

From 10 p.m. Friday, Oct. 4 to 5 a.m. Saturday, Oct. 5:

  • All lanes westbound I-90 between Island Crest Way on Mercer Island and I-5 in Seattle will close
  • I-90 pedestrian walkway will stay open

Maintenance crews will also clean the tunnel walls, lights, and catch basins inside the Mercer Island Lid as well as catch basis on the I-90 floating bridge.

People traveling tonight can use alternate routes like State Route 520 and I-405, but  keep in mind tolling will remain in place.

RELATED: Meet the man behind the technology that makes the light rail traveling the I-90 Floating Bridge possible

RELATED: 10 more years of construction as state wraps up SR 520 project