South Downtown I-405 Access Study

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I-405 corridor in Bellevue

The City of Bellevue has been actively involved in efforts to improve mobility and reduce congestion on I-405 since the late 1990s. The Washington State Department of Transportation’s (WSDOT) I-405  Master Plan was completed in 2002 and calls for multimodal improvements intended to reduce traffic congestion, expand travel options and improve trip mobility within the corridor.

Vicnity Map I-405 Downtown Bellevue

Study Underway

The I-405 Master Plan envisions a new half-diamond interchange in Bellevue, south of the NE 6th Street interchange. The City of Bellevue is conducting a study to develop, evaluate and identify a preferred alternative location(s) and configuration(s) for consideration by WSDOT in conjunction with completion of the Master Plan.

Proposed development along 114th Avenue Southeast, near the East Main light rail station  and within the Wilburton area has created a pressing need to identify a preferred connection alternative. Selecting a preferred alternative will enable the City to set clear expectations for property owners and developers regarding right-of-way needs and site access options.

Additionally, selecting a preferred alternative with a cost estimate is also necessary to meet state legislative timelines for the next funding opportunity toward implementing the I-405 Master Plan.

This study builds upon analysis done by WSDOT in 2015 where eight potential access alternatives at various locations were evaluated, including NE 2nd Street, Main Street and Lake Hills Connector. A connection at Main Street is no longer being considered as it is inconsistent with city-adopted plans and policies. Additional options and a “no build option” will be further considered.

City Council Consideration

An update on this study was to be presented to the City Council April 20. The City Attorney’s Office determined that the meeting could not be conducted as it did not satisfy the “necessary and routine” requirements for City Council meetings as per the Governor’s issued Emergency Proclamation due to the COVID-19 crisis. 

A summary of what would have been presented to the City Council has been drafted to provide additional background.

Community Engagement

The City will engage community members through stakeholder interviews and forums, public presentations and online surveys to gain perspective from property owners, developers, neighborhoods and community- and business- based organizations. This outreach will educate the public on the purpose and need of the study, inform the public of alternatives studied, and receive input.  


Community engagement will begin in May/June 2020. By late fall it is anticipated that a preferred alternative will be presented to the City Council for consideration.