Sound Transit Updates ST3 Plan Amid FinancialConstraints

On Thursday, Sound Transit Board Chair Dave Somers will share a resolution to update the Sound Transit 3 system plan. This update will help align the agency's future Link extensions with the available funding. Due to record-breaking inflation and more accurate price estimates, Sound Transit is facing a $34.5 billion funding shortfall. In March, the agency shared three potential approaches it was considering for re-aligning ST3. These suggestions alarmed Sound Transit tax payers and transit advocates. Over the past few weeks, groups supporting different projects have sprung up, demanding that Sound Transit build the voter-approved system.

Map of funded ST3 projects under Resolution No. R2026-11. (Sound Transit, edited by author)

The resolution designates some projects to be fully funded through completion, some to be partially funded through planning or design, and others to be deferred until additional funding becomes available.

Project	Funded by Resolution R2026-11
Ballard Link Extension	- Construct CID to Seattle Center - Design Seattle Center to Ballard
West Seattle Link Extension	- Construct to Alaska Junction, skipping Avalon station
Everett Link Extension	- Construct to Everett
Tacoma Dome Link Extension	- Construct to Tacoma Dome
Graham St and Boeing Access infill stations	- Design both stations
T Line Extension	- Construct to Tacoma Community College, opening pushed back from 2035 to 2043
Kirkland-Issaquah Link	- Construct full line, opening pushed back from 2041 to 2050.
DuPont Sounder Extension	- Planning phase
Maintenance Facilities (Link North, Link South, Sounder, ST Express)	- Construct Link and Sounder maintenance facilitates - Partially fund ST Express bus base

The deferred projects include Sounder South platform extensions and access improvements, the rest of the ST Express bus base, and parking improvements at Link, Sounder, and Stride stations.

• Tacoma Dome Link Parking
• Everett Link Parking
• Stride Parking
• North Sammamish Park & Ride
• Edmonds & Mukilteo Parking and Access
• Bus on Shoulder Project
• SR 162 Corridor Improvements
• Sounder South Platform Extensions
• Sounder South Access Improvements
• ST Express Bus Base (remainder)

Link Ridership Projections

This new proposal to defer parts of ST3 comes as the existing Link system breaks ridership records. The two busiest days in the system's history occurred in February (Super Bowl parade) and March (Crosslake Connection opening). The 1 Line averaged 118,095 weekday boardings in February, breaking the previous record set in October 2025. Sound Transit has not released ridership data for March or April yet, but strong 2 Line ridership is expected to push total Link ridership well above current levels.

If Sound Transit wants to build a Link system with the highest possible ridership, this is not it. Ridership projections for ST3 Link projects show the Ballard Link Extension carrying more passengers than every other extension combined.

Projected daily ridership on each ST3 Link extension in the given horizon year. (Sound Transit)

To understand why Sound Transit would even consider building a system that does not maximize ridership, we need to look at the agency's financial and political constraints.

Borrowing Constraints

Sound Transit is not running out of money. The agency collects over $2 billion per year in sales, rental car, and motor vehicle excise taxes. About $200 million of this funding goes to paying down existing loans from Sound Move and ST2 projects. Another $200 million is spend on service delivery. This includes track and vehicle maintenance, passenger information systems, crossings and train control, and more. The vast majority of Sound Transit's funding is directed towards system expansion. The 2026 system expansion budget includes the Stride lines, Ballard Link Extension, West Seattle Link Extension, and more.

2026 System expansion budget by project (Sound Transit)

Sound Transit issues bonds and takes out loans borrowing against future tax revenues to build projects faster and more efficiently. The resulting debt is paid off over time, but there are limits to how much debt Sound Transit can hold at any given time.

By Washington state law, Sound Transit's debt cannot exceed 1.5% of the assessed valuation of real property located within the regional transit authority district. Additionally, the debt service coverage (total revenue minus operating costs, divided by debt service) cannot fall below 1.5 times the total debt service. These two constraints prevent Sound Transit from simply borrowing the necessary funds to build all ST3 Link projects on time. Instead, it needs to prioritize some projects over others to space out the loans.

Sound Transit Subareas

When deciding which projects to prioritize, Sound Transit must consider its subarea structure. For planning and budgeting purposes, the Sound Transit taxing district is split into five subareas: Snohomish, North King, East King, South King, and Pierce. In most cases, tax revenue collected in a subarea must be used on projects or services for that subarea.

The subarea split is the main driver for why Everett and Tacoma Dome extensions are not affected in the resolution. North King and East King subareas generate the highest revenues, but have also spent more on Link construction than the other subareas. Meanwhile, Snohomish and Pierce subareas generate less revenue, but do not have significant debt obligations from previous Link projects.

Sound Transit sub-area map

Other factors that support prioritizing the Everett Link Extension and the Tacoma Dome Link Extension are the project's lower cost increases and overall budget compared to projects in Seattle. The Ballard Link Extension is the most expensive ST3 project by far, as it includes a second Link tunnel under downtown Seattle.

The New Downtown Seattle Transit Tunnel (DSTT2) is an exception to the sub-area funding rule. Sound Transit considers the tunnel (Between CID and Denny) a regional investment, and funding for the tunnel will be split across the five sub-areas based on ridership projections. Sound Transit spokesperson Amy Enbysk shared the following DSTT2 planning, design, and construction costs split with Seattle Transit Blog. This split was based on planning assumptions in February 2026 and is subject to change.

Snohomish: 13%
North King: 51%
South King: 13%
East King: 14%
Pierce: 8%
Systemwide: 1%

Despite splitting the DSTT2 costs, building the full Ballard Link Extension (as currently designed) would require borrowing so much money that projects in other subareas would be deferred for decades. Building the cheaper extensions to Everett and Tacoma Dome still allow some of the other projects, such as West Seattle, to proceed with minimal delay.

Redesigning ST3

Some transit advocates have pushed Sound Transit to think bigger and redesign ST3. These arguments include using shorter, automated trains for Ballard and/or West Seattle, skipping the DSTT2, and improving bus service instead. Sound Transit has largely ignored these requests, though it did study deferring the second tunnel at Boardmember Claudia Balducci's request. Somers has since taken the option to defer the second tunnel off the table.

The proposed ST3 alignment is not a transit system designed to maximize ridership or connectivity. Instead, it is the result of a challenging financial environment, an emphasis on subarea equity, and artificial limits imposed on the transit agency.