East Marginal Way Corridor Improvement Project

Updated: February 7, 2020

What’s happening now?

We recently reached our 60% design milestone for the North and Central segments. We will continue advancing design throughout 2020 but we want your feedback on design so far! Click here to take a short survey and let us know what you think of our planned improvements for E Marginal Way S. 

If you commute by bike on E Marginal Way S, you may see our project team alongside the bike lane next week. Stop by to learn more about the project and ask us any questions you have! Below are the details for where we will be:

Tuesday, February 11: 7:15 - 8:45 AM near S Hanford St and S Horton St

Wednesday, February 12: 4:15 - 5:45 PM on S Spokane St near the West Seattle Bridge

Once design is complete later this year, we will move into construction in 2021. We plan to break the project into several phases of construction to build critical safety features as early as possible.

Phase 1 work will likely include:

  • Constructing a protected bike lane (PBL) between S Atlantic St and S Spokane St with full separation between people biking and people driving and delivering goods to make biking safer and more predictable in the spirit of Vision Zero
  • Rebuilding the existing traffic signal at S Hanford St to protect all bicyclist and motorist movements, and potentially relocating the railroad tracks at S Hanford St to provide more space between truck traffic and the bicycle facility
  • Constructing a new traffic signal at S Horton St to provide a protected diagonal crossing for bicyclists
  • Updating the existing signals at S Atlantic St and S Spokane St to work better with the changes to the corridor

We will continue to pursue funding for design and construction on other portions of the project as opportunities become available. We currently do not have a funding schedule and expect that it could take several years before funding is identified.

Comments and questions are welcome by emailing EastMarginal@seattle.gov or calling 206-684-8105.

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Project Overview

As Seattle grows, improvements to freight mobility are essential to promote regional and international economic competitiveness. East Marginal Way is a major freight corridor that provides access to the Port of Seattle terminals, rail yards, industrial businesses and the regional highway system, and between local Manufacturing and Industrial Councils (MIC's). It is also a designated Heavy Haul Route, critical last-mile connector and vital route for over-sized trucks or those carrying flammable cargo.  In addition, the corridor provides a major connection for people who bike between the West Seattle Bridge Trail, downtown, and the SODO neighborhood.

This project will:

  • Improve safety and reliability in the movement of people and goods
  • Support freight loads by rebuilding the roadway
  • Promote efficiency through signal modifications and intelligent transportation systems (ITS)
  • Improve safety by better separating non-motorized modes from freight traffic

Click here to view the 60% design overview.

Project Details

North Segment

For the North Segment (S Atlantic St to S Spokane St), design includes:

  • 2-way protected bike lane on the east side of the street between S Atlantic St and S Spokane St
    • From S Atlantic St to approximately S Massachusetts St, this bike lane would be under the SR-99 Viaduct
    • From S Massachusetts St to approximately S Holgate St, the bike lane would be to the east of E Marginal Way with a significant buffer from the roadway
    • From S Holgate St to S Hanford St, and in some sections between S Hanford and S Spokane St, the bike facility will be adjacent to the roadway but buffered by a concrete barrier
  • Multi-use path on the west side of the street between S Horton St and S Spokane St
  • New signalized diagonal bicycle crossing at E Marginal Way S and S Horton St
  • Reconstructing the E Marginal Way S roadway to heavy haul standards from approximately S Massachusetts St to S Spokane St
  • Replacing the existing water main in areas where the roadway will be reconstructed north of S Horton St
  • Rebuilding the sidewalk on the west side of E Marginal Way S adjacent to the roadway reconstruction north of S Horton St

North Segment cross section.

East Marginal Plan View - Hanford Options
PBL crossing at S Hanford St
East Marginal Plan View - Hanford Horton Options
PBL crossing at S Horton St

These recommendations are based on the public’s desire to reduce conflicts between bicyclists and trucks accessing Port of Seattle driveways and are consistent with existing northbound bike flow. Our design team evaluated placing the diagonal crossing at S Hanford St to take advantage of the existing traffic signal, however our analysis shows less delay for all users if we create a new signal at S Horton St.

Central Segment

This project aims to provide a clear route through the confusing area between S Spokane St and Diagonal Ave S.

Our proposed design includes a shared use path on the east side of E Marginal Way S south of S Spokane St. At approximately mid-block, the path will cross to the west side of the street at a marked crosswalk, where it will continue to Duwamish Ave S. From Duwamish Ave S, people walking and biking will use a marked crosswalk to continue on the west side of E Marginal Way S past the concrete plant. This would mark the beginning of a multi-use pathway heading south.

Freight improvements proposed in the central segment include reconstructing the surface street of E Marginal Way S to heavy haul standards, improving wayfinding and lighting to make it easier to navigate the area, and ITS improvements including a Dynamic Message Sign at S Alaska St.

Proposed central segment improvements

South Segment

The South Segment (Duwamish Ave S to 1 Ave S) is part of SR 99. There are neither bike facilities nor sidewalks on the west side of the street, and some missing sidewalks on the east side. These factors contribute to a challenging walking and biking environment for people trying to move through the area. 

In March 2018, SDOT completed a preliminary design for this section that included:

  • Pedestrian improvements at each existing traffic signal
  • Constructing missing sidewalks on the east side of the street
  • Transit stop improvements
  • Signal enhancements where appropriate to improve predictability and safety for people walking and biking

We have developed a proposal to improve the connection to the 1st Ave bridge, however funding constraints will prevent this from being part of the core project scope. If we identify a grant opportunity that allows us to include this connection, we will do so.

Design and construction of this portion of the project is currently unfunded. We will continue pursuing funding opportunities to advance the South Segment but currently do not have a schedule for this portion of the project.

Initial analysis of this section of the project also included evaluation of whether a lane of traffic on SR 99 could be removed to allow construction of a protected bike lane, as called for in the Seattle Bicycle Master Plan. Due to traffic volumes on SR 99, removing a motor vehicle lane was not recommended.

East Marginal Map South Segment
Click to enlarge

Project Benefits

  • Improved freight mobility –Support the economic vitality of our region including the Port of Seattle and local industrial businesses.
  • Safety - Better access and connections in combination with separating non-motorized modes to reduce potential conflicts.
  • Better pedestrian and bike connections – New and upgraded facilities for people walking and biking also improves access for employees using transit or non-motorized modes to get to work in the area.

Project Funding

Funding to evaluate alternatives and complete early design is provided by the 9-year Levy to Move Seattle, approved by voters in 2015. Learn more about the levy at Levy to Move Seattle.

In 2019, we secured grants to complete full design for the north and central segments, and to begin Phase 1 construction.

Schedule and Cost Estimate

The project is at 60% design completion. We expect to begin construction in 2021. SDOT will continue to pursue design and construction funding for additional phases of the project.

Phase 1 schedule


  • Data collection
  • Early design workshops
  • Preliminary traffic analysis


  • Online Open House and Survey from Spring to Summer
  • Spring
    • Develop options
    • Seek input on options
  • Summer
    • Create preliminary engineering designs
  • Fall
    • 10% design complete


  • Winter-Spring
    • 30% design complete


  • Restart design


  • Complete design for North and Central segments


  • Begin construction


  • Complete Phase 1 construction

Public Outreach

We are currently advancing design based on public input and comment collected from 2015 to present.

In fall 2019, we worked with businesses in the Central Segment to develop a preliminary concept for the area. We will continue working with businesses and community groups to develop design.

To request a briefing for your organization or for more information, please send an email to EastMarginal@seattle.gov.

Nearby Projects

S Lander St Bridge Project

Georgetown Mobility Study

Project Materials

60% Design Overview

Phase 1 60% Design Plan Set (selected sheets)

Phase 2 60% Design Plan Set (selected sheets)

Project Fact Sheet

East Marginal Way project INFRA grant, submitted 2/25/20

Project Contact

Dan Anderson, Communications Lead

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