Project Title & Location
SR 520 W Lake Sammamish Parkway to SR 202 - Redmond

Project Description
This project will widen State Route 520 to eight lanes between the West Lake Sammamish Parkway Interchange and the State Route 202 Interchange. The widening includes auxiliary lanes, ramps and high occupancy vehicle (HOV) lanes.

Contractor/Consultant
CH2MHILL selected as design consultant for project.

Recent Progress

The addendum to 1992 EIS has been completed and is being issued on June 7, 2006.  There is no public comment period. 

A Cost Risk Assessment for the project has been completed.  The CRA confirmed that we are within budget to deliver the project.

The Construction Plans for the Flyover Ramp from westbound SR 202 to westbound SR 520 are on schedule for a December 2006 ad date.   Construction is expected to begin by Spring 2007 and the Flyover Ramp is expected to be open before the end of the year.

WSDOT has reached verbal agreement with the City of Redmond to have the City include the SR 520 leg of the Union Hill Road intersection in the City’s upcoming Union Hill Road Phase 2 project which will go to ad in Spring 2007.  This will complete improvements to the Union Hill Road intersection by fall 2008.

The remainder of the SR 520 project from Westlake Sammamish Parkway to Union Hill Road is on schedule for the October 2008 ad date.  Construction is planned to begin by Spring 2009 and open to traffic by Fall 2011.

Design Construction Impacts

The Flyover ramp project will require closure of SR 202 for several nights in the vicinity of SR 520 to set bridge girders across SR 202. 

The Traffic Analysis for SR 520 WLSP to SR 202 project shows that the existing congestion (LOS F) on eastbound SR 520 between 51^st and WLSP will not be improved by this project.  The project on eastbound SR 520 from 51^st to WLSP would construct an auxiliary lane and improve the weave that exists in this area of SR 520.  This project is in the 20 year plan however it is unfunded at this time.

Environmental Impacts / Compliance

WSDOT is seeking concurrence from DOE, NMFS, USFWS, and Maintenance on the use of Storm Water Filters for water quality treatment in project area adjacent to Bear Creek. The right of way constraints of Bear Creek and Marymoor Park and the low roadway elevations on SR 520 relative to the Sammamish River make other methods to achieve water quality impractical. 

Impacts to Traffic

No significant impacts expected until early 2007 when the flyover ramp project is under construction.  The project will require the closure of SR 202 between 11 PM and 4 AM to set the flyover bridge girders across SR 202.  This work will occur during the summer of 2007.

Mitigation efforts will include a comprehensive public awareness campaign.

Right of Way is currently not required.

Planned vs. Actual Expenditures
(Total Project Cost)

Nickel funds included in above costs

2005 Transportation Partnership Account