Columbia St 2-way Transit Corridor

What's happening now?

Street reconstruction on Columbia St from 1st Ave to 3rd Ave will begin as soon as November and is expected to wrap up by spring 2018.

Project elements:

  • Street reconstruction
  • Traffic signal modifications
  • Curb bulb modifications
  • Water main replacement

Construction impacts:

  • Details about the construction schedule and sequencing will be available and shared a few weeks before groundbreaking
  • Out goal is to keep at least one lane of Columbia St open during construction. There may be weekend lane closures that temporarily limit access to parking garages. We’ll be in close contact with building owners and managers, tenants, and residents prior to any such impact
  • Please email Dan Anderson at to get on the construction update email list for timely information

Project Overview

The Alaskan Way Viaduct Replacement Project is underway and expected to be complete in a few years. When the viaduct is demolished and the new tunnel opens to traffic, our regional transit pathway from West Seattle and southwest King County will need to be rerouted onto surface streets.

To accommodate this change, the City of Seattle and King County Metro have developed a plan for a transit pathway on Alaskan Way and Columbia St to get buses to and from the 3rd Ave transit spine. A grant from the Federal Transit Administration is paying for part of this work.

Today, Columbia St is a 1-way street heading westbound that connects to a viaduct on-ramp at 3rd Ave. Our project – the Columbia St 2-way Transit Corridor – will rebuild the segment between 1st Ave and 3rd Ave. The segment between 3rd Ave and Alaskan Way will be rebuilt and converted to 2-way operations as part of the Waterfront Seattle project.

Once done, there will be a new cement street that can handle the higher weight of buses and an eastbound lane for transit and local access to move thousands of people a day into downtown Seattle on our new, post-viaduct transit pathway.

Project Details

The project area is Columbia St from 1st Ave to 3rd Ave. Work includes complete street reconstruction, which means we’ll remove the current asphalt and street base and pave the street with cement. Intersections will be left as-is for now. Some new traffic signals will be added to the intersections to prepare for future eastbound traffic.

The newly paved street will be striped the same way it is today. Two-way operations will only begin once the viaduct is removed and the new streets under it are built and ready for transit in a few years.

While the street is open, our partners at Seattle Public Utilities will replace the water main pipe.



Project Background

This project is being constructed in preparation for the Alaskan Way Viaduct Replacement Project, which is being led by the Washington State Department of Transportation in partnership with the Federal Highway Administration, City of Seattle, Port of Seattle, and King County.


Fall 2017

Construction begins as soon as November.

Spring 2018

Construction ends.


Funding for this project comes from a grant from the Federal Transit Administration managed by King County Metro.



Mailer coming soon.