West Seattle Link Extension: FTA Approves!

United States, May 2, 2025

The ambitious West Seattle Link Extension project, a critical component of the Puget Sound region’s expanding light rail network, has achieved a significant milestone. The United States Department of Transportation’s Federal Transit Administration (FTA) has officially issued a Record of Decision (ROD), signaling the successful completion of an exhaustive environmental review process that commenced in 2017. This crucial federal approval empowers Sound Transit, the regional transit authority, to transition the 4.1-mile light rail extension into its detailed design phase. Approved by voters in 2016 as part of the comprehensive Sound Transit 3 (ST3) capital plan, this extension promises to dramatically enhance mobility for West Seattle residents and commuters. The project aims to slash travel times between key nodes like Alaska Junction and downtown Seattle’s Westlake station by an estimated 50 percent, while significantly boosting transit capacity and reliability in a rapidly growing corridor.

Paving the Way: Regulatory Green Light and Project Origins

The journey of the West Seattle Link Extension to this pivotal stage began with strong public backing, culminating in its inclusion in the voter-approved ST3 plan. This multi-billion dollar initiative is designed to expand high-capacity transit across King, Pierce, and Snohomish counties. The issuance of the Record of Decision by the FTA is a landmark achievement, formally concluding the rigorous National Environmental Policy Act (NEPA) review process. This decision validates that the project has met federal environmental standards and allows Sound Transit to proceed with final design, property acquisition, and eventually, construction. The environmental review meticulously assessed potential impacts on the natural and built environment, incorporating extensive public feedback and technical studies to shape the project’s trajectory and mitigation strategies. This federal endorsement is indispensable for accessing potential federal funding and moving towards project realization.

Defining the Line: Route, Stations, and Operational Enhancements

The West Seattle Link Extension will span 4.1 miles, connecting the existing SODO (South of Downtown) station to West Seattle’s vibrant Alaska Junction neighborhood. The project scope includes the construction of four new light rail stations strategically located at SODO, Delridge, Avalon, and the Alaska Junction terminus. A significant engineering feat within this project will be a new bridge dedicated to light rail transit (LRT) over the Duwamish Waterway. Upon its projected completion by 2032, the extension is anticipated to serve over 24,000 daily riders, with forecasts indicating a growth to between 24,000 and 27,000 daily boardings by 2042. Beyond the substantial reduction in travel time, the extension is engineered to provide a marked improvement in transit service frequency and reliability, offering a dependable alternative to vehicular traffic, particularly crucial given the known vulnerabilities and congestion challenges associated with the West Seattle Bridge.

Strategic Alignment Choices and Community Collaboration

In October 2024, the Sound Transit Board formally selected the preferred alternative for the project, a decision that defined the precise light rail route, vertical profile, and station locations. This selection was the culmination of years of technical analysis, environmental impact studies, and extensive community engagement. The chosen alignment incorporates several key features: a medium-depth tunnel for the West Seattle Junction segment to minimize surface disruption in the dense urban core; a lower height south alignment for the Delridge segment to optimize integration with the existing topography and community; a south crossing alternative for the Duwamish segment, selected for its operational and environmental merits; and an at-grade access station option for the SODO segment, facilitating efficient transfers and connectivity. This meticulous approach to alignment selection underscores Sound Transit’s commitment to balancing operational efficiency with community preferences and environmental stewardship, ensuring the project reflects the needs and values of the areas it will serve.

Integrating Transit into the Urban Fabric

The West Seattle Link Extension is more than just a transit line; it’s a catalyst for enhanced urban living and connectivity. The City of Seattle is actively collaborating with Sound Transit on the planning and design of station context areas. This involves detailed consideration of the immediate vicinity—typically one to two blocks—surrounding each new station. The focus is on creating well-designed public realms, including station plazas, surrounding open spaces, and seamless integration with other transportation modes, particularly bus services, to ensure efficient intermodal transfers. The Seattle Department of Transportation (SDOT) and the Department of Planning and Community Development (DPCD) are jointly spearheading the development of comprehensive street concept plans for these station areas. These plans, informed by ongoing feedback from Sound Transit and local community members, aim to optimize pedestrian access, bicycle infrastructure, and overall placemaking, ensuring that the new light rail stations become vibrant, accessible community hubs. This holistic approach to urban integration is critical for maximizing the project’s benefits beyond mere transportation.

Conclusion: A Transformative Step for Seattle’s Mobility

The issuance of the Federal Transit Administration’s Record of Decision for the West Seattle Link Extension marks a watershed moment for Seattle and the broader Puget Sound region. This project, born from public will through the Sound Transit 3 initiative, is now firmly on the path to realization. The 4.1-mile extension, with its four new stations and strategic Duwamish River crossing, is not merely an addition to the existing infrastructure but a transformative investment poised to reshape the daily commute for tens of thousands. By drastically cutting travel times, enhancing service reliability, and providing a resilient alternative to congested roadways, the extension directly addresses pressing urban mobility challenges.

The careful selection of the alignment, incorporating features like tunnels and optimized station designs based on rigorous technical analysis and robust community input, demonstrates a commitment to responsible and responsive infrastructure development. Furthermore, the collaborative efforts between Sound Transit and City of Seattle agencies to integrate the new stations seamlessly into the urban fabric, focusing on pedestrian-friendly designs and multimodal connectivity, will amplify the project’s positive impacts. This holistic planning ensures that the benefits extend beyond transit riders to enhance the livability and accessibility of the surrounding neighborhoods. As the project moves into the detailed design phase, the West Seattle Link Extension stands as a testament to the region’s dedication to building a sustainable, efficient, and equitable transportation future, promising improved quality of life and supporting continued economic vitality for decades to come.

Key Organizations Involved:

• Sound Transit (Central Puget Sound Regional Transit Authority): The public transit agency responsible for planning, building, and operating regional transit systems, including light rail, in the Seattle metropolitan area. It is the lead agency for the West Seattle Link Extension project.
• Federal Transit Administration (FTA): An agency within the United States Department of Transportation (DOT) that provides financial and technical assistance to local public transit systems. The FTA’s Record of Decision was crucial for this project to advance.
• City of Seattle: The municipal government working in partnership with Sound Transit on various aspects of the project, particularly through its:
  • Seattle Department of Transportation (SDOT): Responsible for city streets, traffic management, and multimodal integration.
  • Department of Planning and Community Development (DPCD): Oversees urban planning, land use, and community development initiatives in Seattle.