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Construction Begins on SR 520/I-5 Express Lanes Connection Project in Seattle

SEATTLE, WA — Washington State Department of Transportation crews recently broke ground on a project that will extend State Route 520’s new transit/high occupancy vehicle system to Interstate 5 in Seattle. The new transit/HOV system will provide a dedicated, reversible connection between SR 520 and the I-5/Mercer Street interchange via the I-5 express lanes.

Crews will add fencing to define the project limits, implement erosion control measures, and confirm utility locations and soil conditions for the upcoming work. The bulk of construction will occur at night or off the roadway and there will be frequent evening and weekend ramp and lane closures, and reductions on SR 520 and I-5.

Once complete, the new reversible lane will work in concert with the I-5 express lanes. When the I-5 express lanes are operating in the northbound direction, the new ramp will connect to eastbound SR 520. The new ramp will connect westbound SR 520 vehicles to the I-5 express lanes when they are operating in the southbound direction.

Initially, only buses will use the connection. The reversible lane will open to carpools when construction of the SR 520 - Portage Bay Bridge and Roanoke Lid Project is complete.

The project also includes:

  • Revising I-5 express lanes to retain the four existing lanes while adding a reversible transit/HOV lane between the I-5/SR 520 interchange and Mercer Street
  • Modifying an existing ramp for reversible operations between the I-5 express lanes and Mercer Street
Metso Minerals - Recycling Eq
Your local Metso Minerals Industries Inc dealer
PacWest Machinery
Westate Machinery Co

The $68-million SR 520/I-5 Express Lanes Connection Project is scheduled for completion in late 2023.

This is the second of four SR 520 projects that make up the Rest of the West improvements. The projects were funded in the 2015 Connecting Washington funding package.

Superior Industries
Your local Superior dealer
Westate Machinery Co
Superior Industries
Your local Superior dealer
Westate Machinery Co
Volvo CE
Your local Volvo Construction Equipment dealer
PacWest Machinery