Implications of the West Seattle Link Cost
Pundits claim West Seattle had been added to the ST3 plan by politicians envious that Ballard gets a light rail connection. It seemed easy to draw another line on the map, but now that Sound Transit published the final Environmental Impact Statement for the West Seattle Link Extension (WSLE) it has become evident that it is far more complex than anticipated. While the ST3 measure promised to bring 37,000 riders for $1.5 billion ($2.4B in 2024 dollars) by 2030, now the price tag has tripled to $7.1 billion (in 2024 dollars), and completion is delayed to 2032, and the ridership forecast for 2042 (after WSLE is connected to the current downtown tunnel) is only 27,000 new riders systemwide.
The delays and cost explosions are directly related to the apparently-unexpected complexity of building the extension as drawn in 2016. The route needs to roller-coaster up over the Duwamish and Pigeon Point, down into the Delridge Valley, and then back up to the Alaska Junction. To ensure southward expansion in the distant future, the station at Alaska Junction was rotated to be north-south, requiring more property takings. To avoid disturbing the Duwamish superfund site, the new bridge needs to stay away from the river shore. The SODO soil is prone to liquefaction in an earthquake, so the elevated guideway pilings have to be extra deeper than normal. The Pigeon Point slope is unstable and requires large retaining walls. The initial setup for tunneling is expensive, even if the tunnel is relatively short.
Sound Transit staff told the Board the more expensive Preferred Alternative would require third party funding, but now they're assuming Seattle, King County, and Sound Transit will somehow find the funding, which is implausible given the large shortfall. If the Board decides to proceed with the current plan, they may choose the same approach as they did during the pandemic finance crunch (realignment"): delay delivery until they collect enough cash from tax payers to avoid breaking the debt ceiling.
As Sound Transit funding and spending is allocated by subarea, any cost increase would delay other projects in the same subarea, in particular the Ballard Link Extension (BLE) through South Lake Union and the second downtown tunnel, which would also delay the connection of the West Seattle line to Downtown. This extension had been promised for 2035 but because of the earlier cost increases, it is currently planned for 2039. Since WSLE is planned to be temporarily finished as a stub line ending at an expanded SODO station, the line will be of limited transit value garnering about 5,800 daily boardings whereas daily ridership for BLE is expected to be more than 50,000. Many riders will simply stay on the bus until WSLE connects to Downtown.
Another option is to build only the Minimum Operable Segment" (MOS) from the SODO station to Delridge Way pending further funding. While the entire WSLE is too expensive, the MOS was highlighted as financially feasible in the Final Environmental Impact Statement. Though if the Board decides to only build the MOS, WSLE will likely have even lower ridership as the Delridge Station will garner very few walk-up riders and Metro plans to continue the current bus service to downtown until the full line is built. Therefore, until the West Seattle Link extension connects downtown, Metro does not plan any bus restructure and no reassignment of bus hours to improve bus services across West Seattle.
West Seattle has already seen a lot of housing development from the RapidRide C and H lines. But housing growth around the stations is limited by the golf course, the steel plant, topography, and more restrictive zoning to the south and west of the Junction. The DEIS stated that Sound Transit only expects a reduction of 400 car trips(in 2042) across the West Seattle high bridge if the WSLE gets built. Meanwhile, it seems connecting Ballard, Interbay, and SLU to Westlake would provide far more opportunities for housing, reduction of car trips (vehicle miles) and bus hour relocation. The sooner this could happen, the better for our region.
Sound Transit says WSLE is necessary as they expect traffic congestion to increase significantly during the next decade, resulting in longer travel times between West Seattle and Downtown for drivers and bus riders. However, if the West Seattle buses travel slowly on Highway 99, SDOT could address this by connecting the busway to the Spokane Street Viaduct by a new on-ramp as I discussed earlier. Bus delays in West Seattle could be fixed with transit prioritization and other spot improvements.
A second realignment for ST3 (or, at least, WSLE and BLE) seems to be looming, and I fear the Board will choose to delay more impactful projects like BLE to finish this high-cost line to West Seattle first.ST3 had a specific delivery item to improve RapidRide C (and D) services in West Seattle before constructing the light rail extension. The Board placed such efforts on hold when they realigned their plan in 2021. If timelines slip again, this would be increasingly important. I hope the Board would consider those incremental bus improvements and focus on building light rail from Ballard/SLU to Westlake and delay WSLE (and potentially the second downtown tunnel) for now.