23rd Ave Corridor Improvements

Updated: June 7, 2019

What’s happening now?

23rd Ave S is back to two-way traffic!

We've returned to two-way traffic on 23rd Ave S between S Jackson St and S Norman St. The southbound detour has been lifted. We still have sidealk, curb ramp, and signal pole work to do. Expect to slow down and stop for flaggers and crews working in the area.

Picture of 23rd Ave S in 2-way traffic operation

King County Metro bus Routes 4 and 48 have also returned to 23rd Ave S south of S Jackson St. For more information about bus schedules, please check King County Metro's website: https://kingcounty.gov/depts/transportation/metro/alerts-updates.aspx 

We started construction May 2018. There's still some work to do before we are completely done with the project. We appreciate your patience as we get closer to completing all the work.

Phase 2

What's coming next?

Phase 2 mapPhase 2 of the project stretches from S Jackson St to Rainier Ave S. Construction began on May 14, 2018 and is expected to last approximately one year. 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

Construction Detour

Phase 2 detour map - click to view larger As of May 16, 2018, there is a southbound detour on 23rd Ave S in place while crews replace the water main and rebuild the street in the northern section of the project area. The detour is expected to last the full duration of construction on 23rd Ave S:

  • Southbound 23rd Ave S between S Jackson St and S Norman St is detoured to Martin Luther King Jr Way S
  • Northbound travel will be maintained on 23rd Ave S, with traffic reduced to one lane
  • We will maintain continual customer access to businesses
  • We will notify you in advance of any restrictions to your driveway; driveway access will be maintained except during temporary restrictions for activities such as driveway rebuilds, sidewalk work, water main installation, paving and striping.

Don’t hesitate to call (206-727-8857) or email us with questions about how to get around your neighborhood during construction.

The construction detour on 23rd Ave S also means long-term transit detours for King County Metro Routes 4 and 48 during construction. King County Metro and the Seattle Department of Transportation have been working together to limit impacts to transit riders during upcoming Phase 2 construction.

  • Route 4: Route 4 is being detoured to Martin Luther King Jr Way S.
    • From community feedback about Phase 1 construction, we heard the importance of maintaining Route 4 service to Judkins Park during construction. Since there is no trolley wire on MLK Jr Way S, Metro is using diesel shuttle buses to service all Route 4 stops south of E Jefferson St. On weekdays, continuing Route 4 riders need to transfer between the regular electric trolley bus and the diesel bus shuttle at E Jefferson St (on weekends, diesel buses serve all of Route 4 so there is no need to transfer).
  • Route 48: Route 48 is also detoured to MLK Jr Way S during 23rd Ave construction.

For more information about transit changes during construction, visit Metro’s website, look for posted Rider Alerts, or call 206-553-3000 (TTY Relay: 711).

Phase 1

23rd Ave reopened to two-way traffic in February 2017.

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 began on May 14, 2018, and is expected to last approximately one year

Phase 3

North of E John St: Now the 23rd Ave E Vision Zero project.


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.


Project area map

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

We are 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.


Current Materials


Previous Materials

Previous translated materials