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SR 520 - Timeline

There are four main projects in the SR 520 Bridge Replacement and HOV Program. Each has its own design and environmental process(es). One of the four projects, the I-5 to Medina: Bridge Replacement and HOV Project, contains subprojects that include replacement of the SR 520 floating bridge and upgrades to SR 520 infrastructure in Seattle between I-5 and Lake Washington.

Click to jump to timelines:
I-5 to Medina: Bridge Replacement and HOV Project
Eastside Transit and HOV Project
Pontoon Construction Project
Lake Washington Congestion Management Project

Program map of lane configuration
Click image for larger, printable version (pdf 640 kb)

I-5 to Medina: Bridge Replacement and HOV Project

Floating Bridge and Landings Project

  • 2012 - Began construction of pontoons in Tacoma.
  • 2012 - Began construction of new floating bridge.
  • 2016 - Opened new floating bridge to traffic.

West Connection Bridge Project

  • 2013 - Began construction of new bridge.
  • 2014 - Completed construction of bridge.

West Approach Bridge North Project

  • 2014 - Began construction of new bridge.
  • 2017 - Opened new bridge to traffic.

I-5 to Lake Washington Project: the Rest of the West 

  • 2015 - Received full funding from Legislature.
  • 2018 - Anticipated start of construction on first phase of project. 
     
     

Eastside Transit and HOV Project

  • 2008 - Conducted environmental scoping.
  • 2009 - Issued environmental assessment .
  • 2010 - Completed environmental process.
  • 2010 - Received permits.
  • 2011 - Began construction.
  • 2014 - Completed major corridor improvements. 
  • 2015 - Completed all construction.

Pontoon Construction Project

  • 2010 - Published draft environmental impact statement.
  • 2010 - Completed innovative pontoon construction testing effort.
  • 2010 - Issued final environmental impact statement.
  • 2011 - Received Record of Decision from FHWA.
  • 2011 - Began pontoon construction in Grays Harbor.
  • 2015 - Completed pontoon construction.   

Lake Washington Congestion Management Project