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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: July 2017

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.

Decommissioning and removal of the old floating bridge from Lake Washington
wrapped up in early 2017. Learn more about the 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 opened in summer 2016 as an out-and-back trail from Medina. The path from the new floating bridge to Montlake is on schedule to open 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 had only 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, together with reconstruction of the SR 520 corridor from I-405 to I-5, improves traffic safety, enhances transit reliability and reduces 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

This project is funded by a variety of state and federal sources, including SR 520 tolling that began in December 2011. The final cost of the Floating Bridge and Landings Project, including preliminary engineering and right of way, was approximately $848 million. 

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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