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SR 520 – Montlake Project – Montlake lid

Traffic shift coming up

Work began in fall 2019 to build the Montlake lid, and the surface of the lid will be in place this summer. As soon as late August, crews will move both Montlake Boulevard and 24th Avenue East onto the lid, giving them space to remove and reconstruct both the Montlake Boulevard and 24th Avenue East overpasses.

During this traffic shift and demolition of the overpasses, you can expect:

  • Lane and road closures
  • Pedestrian and bike detours
  • Noise, dust and vibration from demolition and paving
  • New overpasses complete in 2023

Recent construction activities

To build the lid, crews hoisted heavy girders over the highway lanes to create the framework. Crews are pouring a series of five concrete sections to make up the surface of the lid. These activities began in early April and will wrap up in July.

Support walls for Montlake lid under construction
Building the support walls for the Montlake lid on the north side of SR 520 (looking east)
Large crane lifts girders into place for Montlake lid
Using a crane to lift girders into place over the lanes of SR 520
Crew member walks along new girders in place for Montlake lid
Setting up the deck structure, with the girders in place
Crew members working on Montlake lid
Preparing the deck of the lid prior to pouring concrete
Machine helps crew members pour concrete onto Montlake lid
Pouring concrete to create the surface of the lid