SR 520 Bridge Replacement and HOV Program - Technical documents and legislation

This page contains technical and legislative reports, as well as legislation related to the SR 520 corridor. The documents are listed in reverse chronological order (newest first) by type.

Environmental reports , such as Environmental Impact Statements and many draft design reports, can be found in the Environmental Documents section of the Resource Library.


Transportation reports


SR 520 Transit Station Usage Study


Finance reports


Washington Office of State Treasurer's Report on SR 520 Bridge Replacement and HOV Project Funding Alternatives


  • A Path Forward to Action: Findings and Conclusions for the Alaskan Way Viaduct and Seawall replacement and State Route 520 Bridge Replacement Projects (pdf 335 kb) December 2006


Miscellaneous design and other reports

SR 520 West Side Final Concept Design Report and Public Comment Summary

Read the final report, including Chapters 1-7, here:



Proposal K - Tunnels at East Montlake and the Arboretum

Conceptual Design and Cost Estimate


Corridor Aesthetics Handbook: Ideas for Urban Corridor Design - August 2006


I-5 to Floating Bridge Tunnel Concept Review - April 2006


Catastrophic Failure Plan


Community Construction Management Plans


Legislation related to the SR 520 corridor