West Seattle Link Costs Keep Climbing

A rendering of the West Seattle Link Extension's planned cable-stayed bridge over the Duwamish. (Sound Transit)

Last week, Sound Transit released the Final Environmental Impact Statement (FEIS) for the West Seattle Link Extension (WSLE) ahead of its scheduled publication date of September 20. Although there's technically one more comment period allowed for the FEIS, the massive document and its findings present a detailed review of each of the potential alternative paths Link may take from SODO to West Seattle.

Although the FEIS is focused on a vast range of potential tangible and intangible impacts the project may have, left unstated are the potential impacts of the project costs significantly exceeding Sound Transit's assumptions in their 2021 Realignment.

Inflationary Measures

In 2016, the Sound Transit 3 ballot initiative featured the West Seattle to Downtown Seattle Light Rail" project, with an estimated capital cost of up to $1.53 billion ($2.3 billion in 2023 dollars) for approximately 4.7 miles of grade-separated light rail and service at five stations (Stadium, SODO, Delridge, Avalon, and Alaska Junction). We've always known bringing light rail to West Seattle would be difficult, and support for the project became strained after early EIS analyses revealed likely project costs to be nearly double the ST3 estimate.

At the time, several of the more-expensive options were caveated with an acknowledgement the more-expensive options like tunneling under Alaska Junction, would require third party funding" - that is, additional funding from a municipality or some other benefactor - to be built by 2032. With this in mind, the Board selected a preferred alignment" which includes a second set of at-grade tracks at SODO Station, a high bridge over the Duwamish Waterway south of the West Seattle Bridge, an aerial station in Delridge, a slightly below-grade station in Avalon, and an underground station beneath Alaska Junction.

Summary map of the various alternatives reviewed for the West Seattle Link Extension (Sound Transit)

After selecting their preferred alignment, the Sound Transit Board requested a handful of further studies" with the hopes of saving costs, reducing impacts on businesses and residences, and improving rider experience at key transfer points. As noted in the staff memo summarizing the results of these further studies, most of the refinements resulted in additional project costs.

It appears these cost increases, in conjunction with the well-documented inflationary spike in construction costs and similar spike in land values through the region, have contributed to the preferred alternative's new estimated cost of $4.95 to 5.45 billion in today's dollars.

A segment-by-segment comparison of the cost estimates from the 2022 WSBLE DEIS and the new WSLE FEIS.

Sound Transit wrote in the FEIS:

Cost estimates reflect increased project costs due to steeply rising real estate prices and other construction expenses, and costs resulting from more advanced design that provides a better understanding of project scope and mitigation [...] Sound Transit, City of Seattle, and King County acknowledge there may be shared responsibility to address the additional cost difference between the final project to be built and the realigned financial plan through either additional funding or cost-savings opportunities."

Yesterday, the Seattle Times ($) published a report including updated estimates from Terri Mestas, Sound Transit's new Deputy CEO of Megaproject Delivery who shared previously-unpublished preferred-alignment costs between $6.7 and 7.1 billion. These costs are reportedly based on the actual design of the preferred alignment undergoing preliminary engineering. The FEIS cost estimates are derived from a unit cost" table reportedly developed in coordination with heavy civil construction firms, but the $6.7 to 7.1 billion estimate is a bottom up" calculation based on designs which have almost reached the stage of 30% completion. It is unclear why the near-30% design estimate and unit cost estimates disagree. From the article:

The numbers are upsetting to all board members, especially me," said transit board chair Dow Constantine, a lifelong West Seattle resident. I am very anxious to leave all of this planning behind," and finish the design to learn the real costs, he said. The worst thing we could do right now is be paralyzed and slow the project. Delay decreases the benefit and increases the cost," said Constantine, who is King County executive.

With Sound Transit's long-term financial plan expecting project costs of just under $4 billion, the agency, the City of Seattle, and King County seem to have an extremely steep hill to climb to be able to afford luxuries like a skyline-changing cable-stayed bridge or tunnelling to an underground station in Alaska Junction.

Tightening the Belt

Although it's not the first time Sound Transit's had to search the couch cushions to afford a project, it may need to consider much more severe cost-savings options. These options include delaying completion of the full extension by building a minimum operable segment" from SODO to Delridge, considering less-expensive construction methods for the high bridge over the Duwamish, and reverting to an all-above-ground alignment as described by the representative project" in ST3, but none of these options should be considered low-hanging fruit.

Further changes to the Preferred Alignment would require rework of the preliminary engineering effort already under way. As recently referenced in Sound Transit's staff recommendation against the addition of yet another alternative station location to the Ballard Link Extension EIS process, taking time to assess new alternatives come with its own significant cost: nearly $50 million for each month of delay. Attempts to reduce cost estimates now by altering the preferred alignment may be negated by the simple fact that pouring concrete tomorrow will be more expensive than pouring it today.

Regardless, there does not appear to be much more space for cost-savings refinements between SODO and Avalon, with the Preferred Alignment adopting the lowest-cost alternatives for the SODO, Duwamish, and Delridge segments. West of Delridge, though, there are a few cost-savings options which are still on the table: 1) building an elevated terminus at Fauntleroy and Alaska; 2) cancelling Avalon Station, and; 3) building the minimum operable segment.

Reconsidering Alaska Junction

Although tunnel stations are attractive due to the reduced short-term construction impacts and fewer long-term displacements, the preferred Medium Tunnel" alternative (WSJ-5b) is estimate to cost $700 to 750 million more than the Elevated Fauntleroy Way Alternative" (WSJ-2). Sound Transit summarizes differences in ridership and impacts for each of the studied segments the table below.

WSLE FEIS Chapter 2, Table 6-4, Projected Ridership and Key Impact Differences - West Seattle Junction Segment.

Of course, the most striking differences are in the potential displacements; the elevated alternative with a station over Fauntleroy Way would displace over four times the residents (but about half the businesses) as the underground alternative. On the other hand, WSJ-2 is the only alternative to show notably higher estimated ridership than other options, likely due to the station location being two blocks east of the rest of the alternatives. The report notes ridership would be about 5% higher due to higher numbers of walk, bike, and drop-off/pick-up trips.

Alternative WSJ-2 would demolish three apartment buildings completed while planning of the extension was underway. From the WSLE FEIS Appendix N2.

When faced with this prospect back in 2022, Sound Transit staff reported that due to land acquisition costs associated with going overground, the expense of drilling a subway would only be slightly more expensive than the elevated alternative. Now we can see this is clearly not the case. It seems that once again, the Board must seriously weigh the capital cost of drilling a tunnel against the political cost of demolishing hundreds of newly-built apartments.

And Then There (May Only Be) Two

Another difficult decision lies in the other cost-savings concept: the deletion of Avalon Station. First considered in one of the further studies" completed in 2023, the Board apparently hoped that by cutting one of the three new stations planned for the line, it might to be able to afford a tunnel to Alaska Junction.

Unfortunately, the apparent savings of $350 to 400 million with alternative WSJ-6 are partially negated by increased costs to start the tunnel in Avalon, with the corresponding Delridge segment (DEL-7) estimated to cost $150 to 200 million more than the preferred alternative. For relatively meager savings of $200 million, this alternative would generate 300 fewer daily boarding and reduce the project to two new stations (elevated at Delridge and underground at Alaska Junction), an expanded SODO station, and a very shiny cable-stayed bridge over the Duwamish.

Sound Transit did not study an option to skip the Avalon station and stay elevated to Fauntleroy, an alternative which may have been prudent to review in the face of high tunneling costs.

The Minimum Operable Segment

If the full project is found to be no longer affordable on Sound Transit's realigned schedule, the agency has little choice but to delay completion. To continue making progress on the project, the Board could choose to begin work on the minimum operable segment", or MOS, which would defer construction west of Delridge to a future date. Sound Transit has already floated this concept for the Ballard Link Extension in its earlier consideration of opening the extension to Smith Cove in 2037 then finishing the extension to Ballard in 2039.

For West Seattle, the segments from SODO to Delridge would be built first, with the rest of the extension to Alaska Junction finished later. How much later would depend on the cost of building the MOS, which is not presented in the FEIS. Based on the costs to build the SODO and Duwamish segments, though, the MOS would cost at least $2.65 to 2.95 billion not inclusive of the costs to build the temporary terminal station in Delridge.

Critical Support

Perhaps this latest cost increase will simply reinforce criticism of the project, but the choice remains between sparing no expense (no matter the cost), delaying for further study, or cancelling altogether. In a city famous for thinking, thinking, and thinking some more before actually doing anything, the return on investment from further studies is swiftly diminishing.

There may be an instinct to question whether voters would have approved a package containing such an incredibly expensive project in 2016; but there is little value in rehashing the same old arguments. The real question is whether Seattle will have the gumption to leverage this transit investment to grow the neighborhoods around these stations even more so than Shoreline, Lynnwood, Mountlake Terrace, Bellevue, and Redmond have around theirs.

Although Seattle should be willing to develop density around existing infrastructure and leverage incremental transit improvements to reduce car dependency city-wide, we must at least be able to plan for significant amounts of transit-oriented development around projects like WSLE to make the most of these major investments.

Looking Forward

In the meantime, the official 30-day public comment period starts on September 20. The Sound Transit Board Executive Committee will be briefed on the results of the FEIS during their today (1:30 to 3:30pm), and the full Board is expected to choose the final project to be built in a subsequent meeting. Once the Federal Transportation Administration issues its Record of Decision regarding the project and preliminary engineering is completed next year, design and pre-construction activities will continue with groundbreaking expected in 2028.