Projects > East/Central Corridor

Residents of east and central King County have called for solutions to clogged highways and aging bridges, as well as a light-rail connection across Lake Washington.

Traffic chokepoints and congestion on the Eastside and in the downtown Seattle core make it tough to move people and goods through the region. Right now, there is no east King County connection to the region’s emerging light-rail system. Rush hour backups on I-405, I-5, and SR 520 as well as other regional roads affect the region's mobility, economic prosperity and quality of life.

The Roads & Transit proposal seeks to tackle the East-Central corridor's major traffic chokepoints and connect the busiest population and job centers through road and transit investments. The plan would:

improve the I-405 corridor with expanded lanes
rebuild the SR 520 bridge with six lanes including two new HOV lanes
address I-5 congestion at several Seattle interchanges
provide light rail 20 hours a day, every few minutes during peak commuter hours, between Seattle, Bellevue and Overlake/Microsoft across I-90
build thousands of new Park and Ride slots

The projects proposed for the East/Central corridor, and the benefits they provide, are described below.

The Roads & Transit plan, developed with input from thousands of citizens, civic leaders, and communities, and years of engineering and design work, is our opportunity to do things differently, on a scale that matches the traffic problems we face.

What is proposed for the East/Central Corridor?

Proposed transit investments

Light Rail: Extends light rail between Seattle, downtown Bellevue and Redmond’s Overlake area. Connects region’s largest population and employment centers with light rail: downtown Bellevue to downtown Seattle in 20 minutes, and Overlake/Microsoft to Bellevue in 10 minutes.

Future Light Rail to Downtown Redmond: Funds additional real estate acquisition, design and engineering to extend light rail to Redmond in this phase and possible construction if funding and cost savings occur.

Direct-Access Bus Ramp I-5 to South Industrial Way: Provides a transit-only ramp at I-5 northbound and South Industrial Way which links directly to the 5th Ave S busway that takes buses into downtown Seattle. This new connection will reduce the delays that currently occur when buses weave across I-5 to exit at South Spokane Street.

First Hill Street Car in Seattle: Develops a street car service between one of the region’s largest employment centers (First Hill) to the Capitol Hill light-rail station and downtown Seattle.

Renton Express Bus North 8th Street Parking Garage: Adds to east King County’s I-405 Bus Rapid Transit network, providing easier connections to transit.

Bothell Transit Center and Parking Garage: Adds to I-405 Bus Rapid Transit network with a transit center/Park & Ride near SR 527/Bothell Way Northeast and Northeast 185th Street in downtown Bothell.

I-90/Issaquah Future High Capacity Transit Planning Study: Begins work for future eastside transit possibilities.

SR 520 Future High Capacity Transit Planning Study: Explores future cross-lake transit possibilities to further expand access to fast, reliable transit options

Proposed road investments

SR 520 Bridge and HOV Lane Project: Provides regional funds toward replacing the earthquake- and windstorm-vulnerable crossing with a new six-lane bridge that increases capacity and adds HOV lanes, shoulders and bicycle lanes in each direction. Identifies full funding strategy for entire SR 520 corridor from I-5 to I-405.

I-405 Bellevue to Renton Project: Builds a new elevated braided ramp to separate traffic on southbound I-405 between SR 520 and NE 8th Street in Bellevue and constructs new access to NE 10th Street. Constructs an additional northbound lane from I-90 to downtown Bellevue. Adds two new lanes in each direction between Renton and Bellevue. Constructs a new HOV direct access ramp at N 8th Street in Renton and adds bicycle and pedestrian paths near Coal Creek Parkway and the Wilburton tunnel.

East Sammamish Plateau Access Project: Constructs northern missing link and retrofits existing portions of roadway to provide needed capacity and congestion relief on north end of Sammamish plateau. Would include curbs, gutters, sidewalks, bicycle lanes, street lighting, storm drainage, landscaping.

SR 167/I-405 Interchange HOV to HOV Direct Connection Project: Provides direct HOV-to-HOV connection between SR 167 and I-405 to reduce weaving and backups for both northbound and southbound traffic at the most congested interchange in the state. Connects I-405 to SR 167 for future HOT (High Occupancy Toll) lanes.

Seattle Mobility Project, SR 99 to I-5:

       I-5 approach, Mercer Street widening: Widens Mercer St to add three westbound lanes between I-5 ramps and Dexter Ave to reduce backups. Converts Mercer St from one-way to two-way street with turn lanes. Improves connections for pedestrians and bicycles.

       Lander Street Improvements: Builds overpass above BNSF train tracks between 1st Avenue South and 4th Avenue South to increase traffic flow for trains, cars, trucks, bicycles and pedestrians.

       I-5/Spokane Street Viaduct: Increases capacity by widening viaduct structure, adding one lane between I-5 and 1st Avenue South, building transit-only lanes and an off-ramp at 4th Avenue South. Adds shoulders and installs a permanent median barrier. Improves safety, freight mobility and traffic flow on the major east/west connection between I-5 and SR 99, Port of Seattle and West Seattle. 

       South Park Bridge Replacement Project: Replaces earthquake-vulnerable bridge that, without improvement, is slated to be closed in 2010. Improves freight mobility for Port of Seattle and manufacturing centers in south Seattle.

Updated 06-28-07

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