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SR 520 Bridge Replacement and HOV Project - Plans

We are addressing the need to ease bridge traffic congestion by moving forward with Gov. Gregoire’s decision to build a six-lane facility in a 4+2 configuration. The new SR 520 will have four general-purpose lanes and two high occupancy vehicle lanes (HOV). See the updated project schedule (pdf 246 kb).

Our next step is to work in collaboration with neighborhoods, officials and organizations to design a connecting west side interchange that works for the region and meets the needs of drivers.

Gov. Gregoire’s findings on the SR 520 bridge replacement concluded:

  • The replacement of the vulnerable SR 520 corridor is a matter of urgency for the safety of the traveling public and the needs of the regional transportation system;
  • Consistent with transportation needs to improve mobility and transit reliability, the replacement should be a structure with four general and two HOV lanes; and
  • Work must continue on funding, design, mitigation and the environmental impact statement.

Please visit Gov. Gregoire's Web site to read more about her findings.

SR 520 Bridge Project

4+2 Lane Plans:
Seattle (jpg 275 kb)
Lake Wash (jpg 209 kb)
Eastside (jpg 248 kb)


4+2 Lane Design Options


4+2 Lane "Footprint":
Seattle (jpg 904 kb)         
Lake Wash (jpg 835 kb)
Eastside (jpg 893 kb)


West side mediation design options:
A3 - Seattle City Council resolution application to the 6-Lane Alternative with no Montlake transit stop (pdf 744 kb)
K - Six-lane corridor with tunnel through the Arboretum and tunnel under the Montlake Cut (pdf 638 kb)
L - Six-lane corridor with shallow tunnel through the Arboretum (Foster Island Berm) and bridge over the Montlake Cut (pdf 605 kb)

4+2 Lane Noise Walls: 
Seattle (jpg 160 kb)
Eastside (jpg 172 kb)


4+2 Lane Environmental Information:
• 
Proposed stormwater facilities (pdf 326 kb)
Effects on the Arboretum (pdf 412 kb)
Effects on Seattle wetlands (pdf 842 kb)
Effects on Eastside wetlands (pdf 1.1 mb)

Existing view of the SR 520 bridge from Husky Stadium
Existing view of the SR 520 bridge from
Husky Stadium.  View enlarged image.


Simulated view of the SR 520 6-Lane (4+2 HOV) Alternative from Husky Stadium
Simulated view of the SR 520 6-Lane
(4+2 HOV) Alternative from Husky Stadium. 
View enlarged image.
Description

The new SR 520 corridor will include six lanes (two outer general-purpose lanes and one inside HOV lane in each direction).

SR 520 will be rebuilt from I-5 to 108th Avenue NE in Bellevue, with an auxiliary lane added on SR 520 eastbound east of I-405 to 124th Avenue NE. Both the Portage Bay and Evergreen Point bridges will be replaced.

Overpasses along SR 520 will also be rebuilt.

Roadway shoulders will meet current standards (10-foot inside shoulder and 10-foot outside shoulder).

A 14-foot-wide bicycle/pedestrian path will be built along the north side of SR 520 through Montlake and the Evergreen Point Bridge and along the south side of SR 520 through the Eastside to 96th Avenue NE.

Noise walls will be built along much of SR 520 in Seattle and the Eastside.

This project will include stormwater treatment and electronic toll collection.

This project will also add five 500-foot-long lids to be built across SR 520 to reconnect communities along SR 520: Roanoke, North Capitol Hill, Portage Bay, Montlake, Medina, Hunts Point, Clyde Hill, and Yarrow Point. The lids will be located at 10th Avenue E and Delmar Drive E, Montlake Boulevard, Evergreen Point Road, 84th Avenue NE, and 92nd Avenue NE.

The floating bridge pontoons of the Evergreen Point Bridge will be sized to carry future high-capacity transit. The project does not include an high-capacity transit alignment.

A flexible transportation plan will provide funding to promote alternative modes of travel and increase the efficiency of the system, including intelligent transportation and technology, traffic systems management, vanpools and transit, education and promotion, and land use as demand management.

For More Information
For more information on our environmental work, funding, tolling, and transportation in and across Lake Washington, please visit the project's Common Questions page.