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

Building a bridge to build a bridge

A large construction crane drives pilings in Seattle's Union Bay, with lily pads on the water and blue sky above.

A crane operator drives bridge pilings into Union Bay as part of the SR 520 Montlake Project.

WSDOT contractor crews are making steady progress on the SR 520 Montlake Project. In the photo above, a crane operator drives pilings into Seattle's Union Bay to support one of two temporary work bridges being built in the bay. Crews are using the trestles to remove the highway's old, structurally vulnerable west approach bridge, and later, to construct a new, seismically updated bridge. The new, 1.2-mile-long span will carry eastbound traffic from Montlake to the new floating bridge. The parallel West Approach Bridge North, which opened in 2017, will then carry westbound-only traffic. Learn more on our Montlake Project webpage

Paddle on, but stay out of the construction zone

Kayakers and canoers will notice new barriers on Lake Washington near the Arboretum. These floating barriers are designed to keep paddlers safely out of the SR 520 construction zone where we're replacing the old, structurally vulnerable eastbound bridge and building a replacement. Check out this video to learn more about how to stay safe while you enjoy the lake this summer!

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