Ballard-Interbay Regional Transportation System (BIRT)

The Washington State Legislature asked SDOT to develop a report on how to improve travel for people and goods in Ballard-Interbay.

At the City of Seattle, we are continuing to follow guidance from federal, state, and local leaders and our public health partners regarding COVID-19. During Governor Inslee's stay-at-home order, SDOT staff are continuing their work on the Ballard-Interbay Regional Transportation System project from their residences. At this time, it is anticipated that the BIRT report will be delivered on-time, by the November 1, 2020 deadline. We will continue our work with agency partners, and the community, from home and will update this website if for any reason the project gets delayed.

Join the BIRT project team for a live presentation on November 2 to learn about the newly released report to keep people and goods moving in Ballard-Interbay.

You'll have the opportunity to learn about the contents of the report, hear about transportation investment concepts that advance efficiency in Ballard-Interbay, and see a timeline and funding sources to replace the Magnolia Bridge and Ballard Bridge. 

Following the presentation, you'll have the chance to ask questions and to share your feedback. Monday, November 2, 6:00 PM - 7:15 PM

What is happening in Q4 2020?

  • Working with our Interagency Team partners to evaluate the draft Magnolia and Ballard bridge replacement timeline and funding strategy
  • Drafting the Ballard-Interbay Regional Transportation System report
  • Submitting final report to the Washington state legislature by November 2, 2020 (one day grace period because Nov 1st is a Sunday)

What happened in Q3 2020?

  • Worked with our Interagency Team partners to evaluate the needs of freight, industrial, and active transportation users in the BIRT study area
  • Analyzed traffic management and operations in relationship to the Ballard and Magnolia bridges and the broader transportation network for person movement, transit, freight, and vehicles
  • Developed a list of potential projects that could be considered to improve mobility in the BIRT study area
  • Prioritized engagement with Interbay employers and employees based on a race and social justice approach
  • Evaluated long-term trade-offs for Ballard and Magnolia bridge replacements and providing recommendations
  • Developed bridge replacement timeline and funding strategy for both Ballard and Magnolia bridges

Project Overview

Ballard-Interbay Regional Transportation System (BIRT) study, is a technical transportation study that will evaluate and recommend future improvements for a reliable transportation system in the Ballard and Interbay neighborhoods. The study will address all types of travel, considering movement of people and goods. A final report will be prepared and delivered  to the Washington State Legislature with recommendations including a timeline for replacing the Ballard and Magnolia bridges. Funding is not allocated to, nor adequate for, the design or engineering of the bridges.


The scope for the BIRT study is defined by the Washington State Legislature. It will be guided by an inter-agency team as dictated by the legislation. SDOT is leading this project in collaboration with the City of Seattle Port of Seattle, Sound Transit, King County, Washington State Department of Transportation, and the Washington State Military. 


This study is a year-long process that began in late Fall 2019 and ends with a report by November 2, 2020. The legislature provided a one day grace period because the 1st of November lands on a Sunday.


Ballard-Interbay is a dynamic area with employment and residential growth, maritime and industrial uses, local and regional freight routes, and an evolving transportation system that includes three future Sound Transit light rail stations. The primary area of study is illustrated on the map below and the Manufacturing Industrial Center is highlighted in yellow. Personal and commercial transportation needs are not just localized and the study will take into account the ways local changes and projects affect travel more broadly, including travel on regional systems such as SR 99 and I-5.

BIRT bus, bike and freight map


The 2019 Washington State legislature allocated funds for the BIRT project. The elements in the scope of work for the study and the timeline for its completion are based on the legislative language below.

ESHB 1160 - Section 311 (18)(a):

"Funding in this subsection is provided solely for the city of Seattle to develop a plan and report for the Ballard-Interbay Regional Transportation System project to improve mobility for people and freight. The plan must be developed in coordination and partnership with entities including but not limited to the city of Seattle, King county, the Port of Seattle, Sound Transit, the Washington state military department for the Seattle armory, and the Washington state department of transportation.

 The plan must examine replacement of the Ballard bridge and the Magnolia bridge, which was damaged in the 2001 Nisqually earthquake. The city must provide a report on the plan that includes recommendations to the Seattle city council, King county council, and the transportation committees of the legislature by November 1, 2020. The report must include recommendations on how to maintain the current and future capacities of the   Magnolia and Ballard bridges, an overview and analysis of all plans between 2010 and 2020 that examine how to replace the Magnolia bridge, and recommendations on a timeline for constructing new Magnolia and Ballard bridges."

Community Outreach

Community engagement will occur at key points during the study process.  Major study deliverables and meetings notes, as well as community outreach opportunities, will be posted on this website. SDOT will continually update the Ballard-Interbay Regional Transportation System study website as the project progresses to provide full transparency and updates about the project to all stakeholders.


The BIRT study is funded in the amount of $700,000 by the Washington State legislature. The funding provides resources for technical analysis and collaboration with agency and community partners. The outcome of this work is a report to the Washington state legislature with recommendations that include a timeline for the replacement of the Ballard and Magnolia bridges. Funding is not allocated to, nor adequate for, the design or engineering of the bridges.


Graphic of project schedule from January to November 2020

Stage One: Background Research and Needs Assessment

  • January 2020: Project Kickoff, Public Meeting #1, Convene Project Partners
  • February 2020: Review Previous Plans
  • March 2020: Traffic Analysis and Forecasts
  • May 2020: Interagency Team Meeting #2 (open to the public)

Stage Two: Alternatives Development and Analysis

  • April 2020: Evaluation Framework and Impact Analysis
  • May 2020: Draft Project Lists and Traffic Management Strategies
  • June 2020: Public Meeting #2, Finalize Bridge Alternatives and Traffic Management Strategies
  • July 2020: Interagency Team Meeting #3 (open to the public)

Stage Three: Recommendation and Implementation Strategy

  • July 2020: Develop Timeline and Funding Strategy
  • August 2020: Interagency Team Meeting #4 (open to the public)
  • October 2020: Draft Report, Public Meeting #3
  • October 2020: Interagency Team Meeting #5 (open to the public)
  • November 2, 2020: Final Report to WA Legislature 

Additional Information

In analyzing future transportation demand for the Ballard-Interbay area, the project will take into consideration future residential growth in nearby neighborhoods and additional employment at sites such as the Armory, Expedia and the Port of Seattle's Terminal 91. It will also adjust to reflect the recommendations of the Mayor's current Maritime and Industrial Lands Strategy.

The study will result in a report to the Washington State Legislature with recommendations on future multimodal transportation improvements and a timeline for replacing the Ballard and Magnolia bridges. The report's analysis may guide future policy decisions and infrastructure investments by the City of Seattle and the State of Washington.

Previous Work

Between 2017 to 2019, SDOT conducted two studies to examine options for replacement of the Magnolia Bridge and the Ballard Bridge. These two bridge studies examine associated costs, risks, benefits, and trade-offs of each option. This Ballard-Interbay area is also part of Mayor Durkan's Industrial Maritime Study that will look at how the city can protect and support industry and port operations.

The construction of the Ballard's Multimodal Corridor that will connect the Burke-Gilman Trail is underway and set to be complete in 2020. In addition to the work we have done, the Washington State Department of Commerce is working on the relocation of the National Guard's armory site, the Port of Seattle is working on a development plan for Terminal 91 Uplands, and Sound Transit is in the process of an environmental review for the Ballard Link Extension.



Get Involved 

We're committed to keeping you informed throughout the planning study. If you would like more information about the project, please use one of the following resources: