The SR 520 Bridge Replacement and HOV Program involves a number of large, individual construction projects for the rebuilding of SR 520. Some of these projects had their own planning, design and environmental process. In addition, the I-5 to Medina: Bridge Replacement and HOV Project was the major planning and environmental process for construction of a new SR 520 floating bridge and all remaining SR 520 infrastructure improvements in Seattle between Lake Washington and I-5 – the "Rest of the West."
I-5 to Medina: Bridge Replacement and HOV Project
Eastside Transit and HOV Project
- 2008 - Conducted environmental scoping.
- 2009 - Issued environmental assessment.
- 2010 - Completed environmental process.
- 2011 - Began construction.
- 2014 - Completed major corridor improvements.
- 2015 - Completed all construction.
Pontoon Construction Project
- 2010 - Published draft environmental impact statement.
- 2010 - Issued final environmental impact statement.
- 2011 - Began pontoon construction in Grays Harbor.
- 2015 - Completed pontoon construction.
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.
Montlake Project
- 2019: Began construction
- 2023-2024: expected completion of construction
SR 520 / I-5 Express Lanes Connection Project
- Spring/summer 2021: estimated start of construction
- Estimated construction duration: 3 years
Montlake Cut Bascule Bridge Project
- WSDOT will conduct additional coordination with community stakeholders and agency partners regarding the scope of the Montlake Cut Bascule Bridge Project.
Portage Bay Bridge and Roanoke Lid Project
- 2023: planned start of construction
- 2029: expected completion of construction