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23rd Avenue Corridor Improvements Project

Improving safety and mobility for all users

Last updated: September 18, 2017

Phase 1 | Phase 2 | Current Schedule | Background | Outreach | Materials | Cost | Contact Us

What's happening now?

Join us for updates about construction!

Starting as soon as April 2018, we will begin constructing improvements on 23rd Ave S from S Jackson St to Rainier Ave S. Come to our next open house to learn more about our plans for construction and how we’ve incorporated community feedback into the design.

Open House
Thursday, October 5, 2017
5:30-7:30 PM
Northwest African American Museum, Legacy Hall
2300 S Massachusetts St, Seattle, WA 98144

Open house materials will also be available on this website from September 26 to October 13. Stay tuned!

Project information line: 206-727-8857


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Phase 2

What’s coming up next?
Phase 2 of the project stretches from S Jackson St to Rainier Ave S. Construction is expected to begin a soon as April 2018 and last approximately 1 year. Be sure to visit our open house on October 5 at the Northwest African American Museum (5:30-7:30 PM) to learn what we know today about how construction will take place, how we’re coordinating with nearby projects heading into construction, and how we’re incorporating community feedback into the final design.

We hosted a design open house on July 19 and an online open house from July 10 – 28. Please stay tuned for a summary of community comments on the City’s plans for Phase 2. The project in this area will help enhance safety and mobility for people who walk, drive, and take transit. Phase 2 improvements vary throughout the length of the project and include:

  • Sidewalk improvements, such as sidewalks, crosswalks, and upgraded pedestrian crossing signals
  • Repaving the street
  • Redesigning the street from four lanes to three (one wider lane in each direction with a center turn lane) from S Jackson St to S Holgate St
  • Installing new storm drains
  • Landscaping and street trees
  • Replacing the water main under the street from S Jackson St to S Norman St
  • Replacing water service pipes and fire hydrants from S Norman St to Rainier Ave S
  • Transit improvements, such as real-time arrival information and bus pullouts (space for buses to stop outside of the flow of traffic)
  • Adjacent Central Area Neighborhood Greenway route

Please call 206-727-8857 or email us at if you would like to learn more about the design for Phase 2 or schedule a briefing for your community group. Sign up for email updates to stay informed.

Phase 1

From June 2015 through early 2017, crews rebuilt 23rd Ave between S Jackson St and E John St. The new street includes:

  • Over 285,000 square feet of new concrete paving
  • 105 new ADA-compliant curb ramps
  • Over 91,000 square feet of new sidewalks and driveways
  • Over 8,000 feet of a new water main to replace the previous, 
    100-year-old water main
  • Over 3,800 feet of new stormwater system (storm drainage) and 12 new storm drain filter systems
  • 77 upgraded pedestrian lights, 87 upgraded street lights, and upgrades to 14 existing streetlights
  • 41 new street trees
  • New bus pullouts and real-time information signs at transit stops
  • New public art at the 23rd Ave and E Union St intersection


The 23rd Avenue Corridor Improvement project includes three phases:

Phase 1: S Jackson St to E John St: June 2015 – spring 2017; major construction activities completed, minor close-out activities in progress

Phase 2: S Jackson St to Rainier Ave S – Construction expected to begin as soon as April 2018 and last approximately 1 year

Phase 3: North of E John St: Now the 23rd Ave E Vision Zero project – Visit to learn more.


SDOT has a total of $43 million in funding through a combination of local, state and federal sources. Phase 1 is estimated to cost approximately $31 million and is fully funded. Phase 2 is funded in part by the 9-year Levy to Move Seattle, approved by voters in 2015.


For a good introduction to the project, be sure to check out our overview video.

The corridor

23rd Ave is an essential arterial that connects a variety of users to businesses, educational institutions and residences in the Central District and beyond. Approximately 13,400-20,000 vehicles use 23rd Ave each day. This area also serves high volumes of pedestrians, bike riders, and transit users (approximately 6,000 daily transit riders).

Why construct improvements on the 23rd Ave corridor? 

Before the start of construction, the 23rd Ave corridor was in poor condition, including:

  • Many collisions (more than 900 reported in five years)
  • Poor road conditions (e.g. potholes, cracked pavement)
  • Narrow lanes
  • Back-ups created by left-turning vehicles
  • Narrow and uneven sidewalks
  • Inadequate buffers between vehicles and pedestrians

Improving safety and mobility in your neighborhood

In June 2015, the Seattle Department of Transportation (SDOT) began construction on 23rd Avenue between S Jackson St and E John St. This is the first phase of a project to improve safety and mobility for people who drive, walk, bike and take transit in the area.

Project improvements vary by phase and include:

  • Modifying 23rd Ave from a four-lane street to a three-lane street - one lane in each direction with a center left-turn lane (key intersections will stay four lanes)
  • New pavement
  • Widening sidewalks to at least five feet and repairing broken and buckling sidewalks
  • Installing new streetlights
  • Upgrading traffic signals to give transit priority at key locations
  • Consolidating bus stops to improve transit speed
  • Replacing a 100-year-old water main that runs underneath 23rd Ave
  • Installing public art near 23rd Ave and E Union St
  • Implementing a greenway adjacent to 23rd Ave, to create a quieter, safer route for people to bike and walk

The new roadway –opportunity for a safer 23rd Ave

The new corridor will have wider lanes – one in each direction – plus a 10-foot-wide center turn lane. The turn lane will allow left-turning vehicles to make a safe left turn, while still allowing thru-traffic to continue through an intersection and down the street.

On streets with 25,000 vehicles per day or fewer, such as 23rd Ave, changing the street design from four lanes to three can increase safety by reducing collisions, reducing speeding, allowing vehicles to turn without blocking traffic, managing drivers cutting in and out of lanes, creating space for wider sidewalks, making streets easier to cross and making it easier for freight and transit to travel. At most bus stops, the road will flare to approximately 18 feet, where buses can pull to the side and vehicles can pass the stopped bus in the travel lane. The City is also working with King County Metro to determine the benefits of electrifying the Route 48 line. The results from the study can be found in the Project Materials section below.

cross section

Get Involved

SDOT is committed to engaging with the community and responding to community needs in the project area. Please stay tuned for more information about future public engagement opportunities, and contact us if you would like to request a community briefing. 

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Project materials

Current materials


Previous materials

Previous translated materials

  • 23rd Avenue Corridor Improvements Project and Central Area Neighborhood Greenway Video
  • Contact information


    Call the project information line: 206-727-8857

    Maribel Cruz
    Project Communications Lead

    To request information in another format:

    If you need this information translated, please call (206) 727-8857.

    Si necesita traducir esta información al español, llame al (206) 727-8857.

    如果您需要此信息翻譯成中文 請致電 (206) 727-8857.

    Kung kailangan mo ang impormasyon na ito na nakasalin sa Tagalog mangyari lamang na
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    Odeeffannoon kun akka siif (206) 727-8857.

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