SR 520 Bridge Replacement and HOV Program


For the most up-to-date information about SR 520 construction activities and planned road closures, check our SR 520 Construction Corner and its interactive construction map. You also can view Montlake Project construction photos taken daily, 'round the clock, by four mounted construction cameras.

Current News

Community's design ideas for Portage Bay project noted in new report

The SR 520 team conducted an extensive public engagement process last summer and fall to solicit community feedback on conceptual designs for the Portage Bay Bridge and Roanoke Lid Project. Our newly published report (pdf 2 mb) summarizes the outreach activities, the public’s design ideas for key project elements, and how WSDOT incorporated those ideas into a refined design concept. In addition, the report’s appendices (pdf 3.2 mb) contain all the verbatim comments from the community.

Want to be a Merchant of Montlake?

Interested in opening a small market or mobile food business in Seattle’s Montlake neighborhood? If so, we want to hear from you! With the recent closure of the Montlake Market, we’re putting out a call for proposals to operate a smaller, nearby temporary market or food service. Our latest email update and our official request for proposals, available on WSDOT’s Contract Ad & Award site, have more information on this opportunity.

Out with the old, in with the new

Crews remove the old SR 520 west approach bridge over Lake Union, alongside a new bridge

WSDOT contractor crews with the SR 520 Montlake Project are removing the 1960s-era highway bridge over Union Bay that for decades connected Seattle to the old, now-replaced SR 520 floating bridge. The December 2019 photo above shows old support columns and girders that crews exposed after cutting apart and hauling away concrete roadway decking. The tall crane rests upon a temporary work trestle that, together with the narrower work trestle at left, crews gradually will extend farther east into the lake. As the old bridge is removed, crews will construct a new, three-lane bridge between the trestles. The new bridge will carry eastbound traffic from Montlake to the new floating bridge. 

After the new structure opens in three to four years, the two-way bridge to its north will revert back to a three-lane, westbound-only bridge. More Montlake Project construction photos can be viewed on the SR 520 Program's Flickr collection.

Temporary eastbound on-ramp in Montlake now open, old ramp through Arboretum permanently closed

WSDOT contractor crews opened a temporary eastbound SR 520 on-ramp in Montlake on Dec. 20 and permanently closed the old eastbound ramp in the Arboretum. The temporary ramp will serve motorists for the next couple of years while crews complete planned Montlake Project improvements, including an enhanced Montlake Boulevard interchange.The graphic below shows how traffic now moves through the Montlake area with the new ramp in place.

 Map of the SR 520 corridor in Seattle's Montlake neighborhood, showing where a temporary eastbound on-ramp opened in December 2019, and an old on-ramp through Seattle's Arboretum park permanently closed.

View a larger image. (pdf 9.2 mb)

Program overview

The SR 520 Bridge Replacement and HOV Program is enhancing public safety and mobility by replacing the highway's aging, vulnerable bridges and making significant transit and roadway improvements throughout the corridor. Built in stages, the construction program's completed and planned improvements extend from I-405 in Bellevue to I-5 in Seattle.

map of the SR 520 corridor's major projects

Click on the map above to visit our SR 520 Major Projects webpage.


Phone: 206-770-3500
Find SR 520 Program contact information: Contact Us


Eastside projectPontoon project