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SR 520 - Floating Bridge and Landings Project

The design-build team will continue to design many elements of this project even as construction gets under way.
The New SR 520 Bridge and Approaches will be built between Seattle and Medina.

Project Photos


Last updated: May 2017

Happy birthday, floating bridge!
The new SR 520 floating bridge opened to traffic in both directions on April 25, 2016. We saluted the new span's first birthday with a short video , an online booklet and a blog post that discuss the bridge's construction and its benefits to the region. The biggest gift of the day, though, was a prestigious international award the bridge project won for engineering excellence. Read all about it and watch this special award video.

Decommissioning and removal of the old floating bridge from Lake Washington
is now complete. Learn more about the recently completed decommissioning process on the What’s Happening Now page.

Want to bike or walk along SR 520?
The bicycle/pedestrian path on the new floating bridge is open as an out-and-back trail from Medina. We don't yet know exactly when the extension of the path from the new floating bridge to Montlake will open, but it's on schedule to happen sometime this fall. Stay tuned.

Please visit the SR 520 Bicycle and Pedestrian Connections page for information about your options to pedal or walk along the SR 520 corridor.

What's happening now?

The SR 520 Floating Bridge and Landings project replaced the old SR 520 floating bridge and approaches from the future west approach structure east of Foster Island in Seattle to Evergreen Point Road in Medina.

Why is WSDOT replacing the SR 520 floating bridge and landings?

After over a half century of use, the old SR 520 floating bridge was showing its age. The bridge's pontoons were vulnerable to windstorms and its support columns were vulnerable to earthquakes.

Additionally, the old bridge only had two lanes in each direction, no shoulders and no HOV lanes. Adding transit/HOV lanes, shoulders and a bicycle/pedestrian path provides greater reliability and more options to accommodate growth in the region.

The bicycle/pedestrian path on the new bridge will also connect to regional trails on either side of Lake Washington, creating additional recreation opportunities.

The End Result

  • A safer structure that is resistant to windstorms up to 89 mph.
  • Two general-purpose lanes and one transit/HOV lane in each direction.
  • Wider, safer shoulders that allow vehicles to pull over in the case of a breakdown.
  • A 14-foot-wide bicycle and pedestrian path on the north side of the bridge.
  • Ability to accommodate light rail if the region chooses to fund it in the future.

Project Benefits

  • The new floating bridge improves transit reliability and travel times.
  • Building components of the bridge in Grays Harbor, Tacoma and Kenmore provided hundreds of jobs throughout Western Washington.

What is the project timeline?

  • Late 2011 - Began pontoon construction in Tacoma.
  • Early 2012 - Began anchor construction in Kenmore.
  • Spring 2012 - Began bridge construction on eastern shore of Lake Washington.
  • Spring 2016 - New floating bridge opened to drivers.
  • Spring 2017 - Completed removal of the old floating bridge.

Financial Information

Financial Data for PIN 852004B
Funding Source Amount ($ in thousands)
2003 Gas Tax (Nickel Funding) $0
2005 Gas Tax (TPA) $167,270
Pre-Existing Funds (PEF) $1,170,192
CWA $0
Total $1,337,462

Project signage will reflect the cost of construction engineering, project bid award and sales tax.

This project is funded by a variety of state and federal sources, including SR 520 tolling that began in December 2011.

Visit the SR 520 Budget and Performance page for additional information. 

This project had a construction change order of more than $500,000. View all change orders.

How can I get more information?


Construction Hotline: 425-576-7098

Twitter: @WSDOT_520

SR 520 Bridge Replacement and HOV Program
999 3rd Avenue, Suite 2200
Seattle, WA 98104

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