East Marginal Way Corridor Improvement Project

Updated: October 28, 2020 

What’s happening now?

The East Marginal Way Corridor Improvement project team applied for funding from the Federal INFRA and BUILD grants earlier this year. This funding would have made it possible for roadway reconstruction on all or part of the roadway north of S Spokane St to happen at the same time as the bicycle facility was constructed. We found out in September that we did not receive funding from the BUILD grant. This means the project will be completed in phases, starting with Phase 1.

Phase 1 construction will include:

  • Two-way protected bike lane (PBL) on the east side of East Marginal Way S between S Atlantic St and S Spokane St
  • Rebuilt intersection and traffic signal at S Hanford St and a new traffic signal at S Horton St
  • Lighting and landscaping along the PBL
  • Potential relocation of train tracks at S Hanford St
Phase 1 does not include roadway reconstruction on East Marginal Way S. This major freight corridor is a priority for SDOT and full reconstruction of the roadway will be completed in a later phase.

We will continue to coordinate project permitting and right-of-way during the project design phase. We are committed to getting the best design for this project, and that includes some extra coordination with partner agencies, including the adjacent railroads. We hope to start Phase 1 construction in 2021, but the permitting process may result in construction starting in 2022. We will provide updates as we reach major milestones in the process.

Thank you to everyone who participated in the East Marginal Way Freight Survey. We received over 120 comments from truck drivers sharing their input on project design. Click here to view the Freight Survey Summary.

Comments and questions are welcome. You can reach us by emailing EastMarginal@seattle.gov or calling (206) 684-8105

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Bike lane enhancements as part of Reconnect West Seattle

The existing bike lane on East Marginal Way S has been enhanced with restriping and refreshing the delineators that prevent vehicles from entering the bike lane. These updates are part of Reconnect West Seattle plans to mitigate traffic during the West Seattle High-Rise Bridge closure. Reconnect West Seattle changes on East Marginal Way S do not impact the East Marginal Way Corridor Improvement capital project, which is due to begin construction as early as 2021.

Read more about these interim improvements on the SDOT Blog.

Photo of bike lane enhancements on East Marginal Way S as part of Reconnect West Seattle

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 Centers (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

Freight Survey Summary

Phase 1 90% Protected Bike Lane at S Horton St

Phase 1 90% Terminal 25 South Driveway

Design Rollplot

US Department of Transportation BUILD grant

60% Frequently Asked Questions

60% Outreach Summary

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
(206) 684-8105

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