Sound Transit Concepts Propose Frequent Bus Service between Seattle and Tacoma in 2022

Sound Transit Express buses on I-5. (Wikipedia/Darrius Wells)

New Sound Transit service concepts for 2022 show that regional bus service could become frequent all day on weekdays and weekends from Tacoma and Federal Way to Seattle. The agency also highlighted other service improvements ahead as the Northgate Link and Tacoma Link Hilltop Extensions open and the pandemic lifts. Underpinning many of the changes are a focus on all-day regional service, ridership patterns that are less peak-oriented and more spread throughout the day, and sustained and stronger ridership in the South End.

Tacoma and Federal Way ST Express bus service improvements

The biggest news on Thursday was a new service concept that would increase frequencies on ST Express bus routes between Seattle, Federal Way, and Tacoma. Sound Transit staff have suggested that all-day frequencies could reach every 15 minutes on the corridor seven days a week. This would match the type of service provided to Snohomish County and East King County where Routes 512 (Everett-Seattle), 545 (Redmond-Seattle), and 550 (Bellevue-Seattle) — and eventually Route 522 (Bothell/Woodinville-Seattle) in October — have all-day 15-minute or better frequencies. Agency staff said that the proposal “responds to continued growth in the South Corridor and recent ridership trends.”

Service frequency oof the Sound Transit ST Express bus network pre-pandemic, October 2021, and in 2022. (Sound Transit)
Service frequency oof the Sound Transit ST Express bus network pre-pandemic, October 2021, and in 2022. (Sound Transit)

Looking at ridership trends by mode and area served, ST Express bus service seems to be performing notably better in the South End than other areas. Data from March showed that South ST Express had 35% of pre-pandemic weekday ridership levels compared to 23% for Link, 22% for North ST Express, 16% for East ST Express, 14% for South Sounder, and 4% for North Sounder. The dropoff and rebound in ridership for South ST Express during the initial period of the pandemic differed greatly from other modes and areas; the dropoff was less dramatic and the rebound was much more pronounced.

Weekday ridership during the pandemic by mode and service area. (Sound Transit)
Weekday ridership during the pandemic by mode and service area. (Sound Transit)

Several ST Express bus services connect Tacoma and Federal Way to Seattle, including Routes 577 (Federal Way-Seattle), 578 (Puyallup-Federal Way-Seattle), 590 (Tacoma-Seattle), and 594 (Lakewood-Tacoma-Seattle). It’s unclear which routes would get the service increases, but this could open up the potential for some routes to be consolidated, adjusted, or running extra trips that don’t extend all the way to the normal route terminal (e.g., Puyallup and Lakewood).

Other changes ahead

On October 2nd, the Northgate Link extension will open allowing Route 522 to be trimmed back to Roosevelt Station. The savings in service hours between there and Downtown Seattle allows Sound Transit to reinvest service hours into an improved service that provides 15-minute frequencies all day, except late evenings. In tandem with the extension opening, Sound Transit is modifying Snohomish County-Seattle ST Express bus service by sending Routes 511, 512, and 513 along with Community Transit 800 series routes to Northgate Station. However, Route 510 and Community Transit 400 series routes will still run to Downtown Seattle.

Additionally, Routes 542 (Green Lake P&R-Redmond) and 556 (Northgate-Bellevue/Issaquah) will be trimmed back to U District Station since light rail service would be duplicative and faster for most riders with the latter route being restored as it is currently suspended. Whether or not companion peak-hour services like Route 541, 544, and 555 return in 2022 remains to be seen but they are planned to remain suspended this year.

Looking ahead to 2022, agency staff highlighted the service levels planned for Sounder, Central Link, and Tacoma Link:

  • South Sounder regional rail service could be restored to the full 13 roundtrips by September 2022. North Sounder, however, may remain at two daily roundtrips, which is half of pre-pandemic service levels.
  • Central Link service levels are proposed to remain at current frequencies, which are every eight minutes during weekday peak hours, every ten minutes during weekday off-peak hours and on weekends, and every 15 minutes during late evening hours. Pre-pandemic, frequency on the line was slightly higher with trains every six minutes during weekday peak hours.
  • Tacoma Link service is expected to improve when the Tacoma Link Hilltop Extension opens in May. Frequency should go to every 10 minutes on weekdays and Saturdays, which is an improvement over every 12 minutes. Likewise, Sunday frequencies should go to every 20 minutes, which is better than the current 24-minute frequencies.

Next steps

Agency staff plan to begin outreach on 2022 service concepts this month with an online survey. Then the agency will spend August and September incorporating any feedback into a final plan to be transmitted to the Sound Transit board of directors for consideration and adoption in October. The budget to be approved in December will formally allocate funding for the corresponding service levels and changes will go into during the normal March and September service change periods.

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Stephen is an urban planner with a passion for sustainable, livable, and diverse cities. He is especially interested in how policies, regulations, and programs can promote positive outcomes for communities. Stephen lives in Kenmore and primarily covers land use and transportation issues for The Urbanist.

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What might be interesting is an express bus between Olympia and Seattle, with stops at Lakewood, Tacoma, and Federal Way, running 15-30 minutes throughout the day.

Something akin to Golden Gate Transit’s #101 between Santa Rosa and San Francisco, or perhaps the (unsubsidized) Oxford Tube between Oxford and London. Fast, frequent, limited stop service available to a wide segment of the population.

Stephen Fesler

I think Seattle-Olympia would be a bit too much for Sound Transit. That would be better as a state-run bus route and I think you’re unlikely to see otherwise, even if Thurston County is annexed into the ST taxing district. But Olympia-Tacoma would make more sense for a regional bus network due to operational considerations. Regardless, Intercity Transit would need to partner with Sound Transit to cost-share on a cross-county Sound Transit route.


It’s unclear which routes would get the service increases, but this could open up the potential for some routes to be consolidated, adjusted, or running extra trips that don’t extend all the way to the normal route terminal (e.g., Puyallup and Lakewood).

Yes, it will be interesting to see how it all shakes out. My guess is, the first thing they do is kill off the 586, the express from Tacoma to the UW. But that won’t save much money, as it makes less than ten round trips a day. The other three buses that serve Tacoma are:

574 — All-day half-hour bus from Lakewood and downtown Tacoma to SeaTac.
590 — Rush hour bus from downtown Tacoma to Seattle.
594 — All-day half-hour bus from Lakewood and downtown Tacoma to Seattle.

They could try and combine the 574 and 594 by simply killing off the 574. Riders from Lakewood and Tacoma would transfer to get to SeaTac. Outside of the early morning hours (where ST could retain the route) there would be merit to that, as the 574 gets very few riders most of the day. I just don’t see it though. SeaTac is not only an airport, it is a Link Station.

There are other peak-only buses, like the 577. They are full, so even if you wanted to try and combine routes, it wouldn’t save much.

That leaves the 578, another all-day half hour bus. It runs from Puyallup to Federal Way to Seattle. One potential way to save money is by simply running the bus from Puyallup to Federal Way. There are about 150 riders who travel between Puyallup and Federal Way and about 200 who board in Puyallup/Sumner/Auburn and keep going to Seattle. The ratio is such that simply truncating that bus in Federal Way could get a significant amount of savings, while losing relatively few riders. I could see that happening, but some riders might be unhappy. The express to Tacoma won’t be running every five minutes, but every fifteen, which will make the two transfer trip from Puyallup/Sumner/Auburn to downtown worse.

Other than that, I really don’t see any significant savings. Of course things change once Link gets to Federal Way. Then the 574 really can be killed off, while the express buses connect seamlessly via the freeway station.


I think combining routes becomes a lot easier once Link goes to Federal Way. At that point, the 574/594 could be combined and you don’t need the one-seat ride between Tacoma and the airport anymore. (The 574 could still do the early morning runs to the airport when Link is out of service if they carry enough riders to make it worthwhile).

The 586 should have been killed off back in 2016.


Yeah, I wrote about killing off the 574 when Link gets to Federal Way.

The point about retaining the 574 for early morning runs is a good one. That is when it gets most of its riders (the northbound 2:13 is the only bus that gets over 30 riders a run).


Looking at the map, the improved service (the blue line) is just Tacoma to Seattle, which suggests the 590 will get the upgrade to all day service and Lakewood service will be more-or-less unchanged. I could see ST simply add 590 trips in between the 594 trips to create 15 minute all day frequency between Tacoma and Seattle. Any bigger rethink of STX service in the area, such as fiddling with the 57X, will probably wait until Federal Way Link opens.

As I speculated below, I don’t think ST is looking to kill off other Pierce service to fund this improvement; upgrading the 590 from peak to all-day doesn’t require a larger bus fleet. I’m also speculating that 59X rather than 57X is the service that has seen the most resilient ridership during COVID.


I’m trying to figure out if the improved frequency comes from combining overlapping routes, or whether it’s actually new service hours in the corridor.


It reads to me that it is a net increase in service hours for the south corridor, as the Northgate truncations likely aren’t going to yield massive time savings. The 522 savings are reinvested the same route, and the prior Urbanst post on the Snohomish restructure also indicated improved service, in particular the 512, to coincide with Northgate truncations, so it’s possible the Snohomish doesn’t see a material change in annual STX service hours until Lynnwood

ST has been clear Lynnwood will result in net decrease of STX hours in Snohomish to fund Link operations; same for East Link eliminating rather than displacing STX hours. But it appears that when Link unlocks truncations outside of a subarea’s territory, that allows for ST to shift that subarea’s service hours into better service on the newly shorter routes.

I’d speculate that the improvement doesn’t occur until 2022 because the Northgate truncations will allow for some of the STX fleet to shift from CT to PT bases. By improving all-day service ST can deploy more service hours even if the STX bus fleet doesn’t change much. Looks like the 512, 522, and 590 will be the primary beneficiaries of running a higher share of the STX fleet all day.


How long until Sound Transit is forced to either restructure Sounder service or let it go? If current ridership patterns persist, all-day service that the express buses provide will seem much more economical.


Politically, Sounder is untouchable because it runs on rails, no matter how high the per-passenger subsidy. Even when Link goes all the way to Everett, Sounder Transit still considers Sounder to Everett (which is no faster than Link will be) untouchbable.

As to what should happen, Sounder is actually two lines covering very different areas, so you can’t just lump the two together into one category. Of the two, the south line has far more ridership potential than the north. The south line would ideally, itself, run all-day, if it weren’t for the fact that BNSF owns the tracks and won’t allow Sound Transit to run trains all day for any remotely reasonable cost. The north line should just be killed to help backfall the funding shortage in Snohomish County link extensions.

Stephen Fesler

The minimal annual cost for North Sounder would not do much salvage timelines for Everett Link, netting less than $350 million total through 2041. But there should be a lot of scrutiny for Mukilteo and Edmonds not rezoning around the stations. The lack of infill stations in Shoreline, Ballard, Interbay, and the Waterfront is also just asinine. The line is designed to vastly underperform its potential. Instead, electeds want to spend more money on parking instead of taking rational actions with zoning and more stations to serve more people.


The minimal annual cost for North Sounder would not do much salvage timelines for Everett Link, netting less than $350 million total through 2041.

Yeah, but $350 million for bus service in Snohomish County, even spread out over 20 years, would be a lot. It would serve way more people, and the subsidy per user would be a lot less.


I see two political openings for Sounder North to be removed.

First will be during the Lynnwood bus redesign. The Lynnwood restructure will be a complete reset of Snohomish transit operations, so ST & CT will have the opportunity to propose STX direct connections between Edmond’s & Mukilteo’s downtowns and Link stations in lieu of Sounder North service. It should be straightforward to sell this as an improvement in service for both cities, even if individual riders are greatly inconvenienced. Providing ‘better than Sounder’ service for these two cities prior to Lynnwood Link would require expensive & low preforming STX routes, which is why this option is not on the table today.

The second will be when the Sounder South capacity expansion project restarts (timing will depend on how strongly Sounder South ridership recovers). Removing the North Sounder service from the BSNF tunnel is an important carrot in ST’s negotiations for addition South easements. North Sounder could be truncation to Interbay (with a transfer to an interbay Link station), but if that proves unfeasible, Pierce & South King leaders will have an incentive to kill off Sounder North, whereas today the other subareas entirely defer to Snohomish on Sounder North as it exclusively comes out of Snohomish’s budget.

Stephen Fesler

ST is confident that ridership will rebound. It also serves a very different set of ridership catchments, so it shouldn’t be thought of the same as the express buses even though Tacoma is a common location served. There’s plenty of stops in between. And in any case, redundancy and alternatives are useful for a complete transit network. Personally, I think Sounder frequencies should be vastly expanded so that it can become all-day regional rail. It would also be helpful if WSDOT approved the RailPlus programme on Amtrak Cascades services between Seattle and Tacoma like is offered between Seattle and Everett (currently suspended). That would give riders more choice, fill empty seats, and provide Cascades more revenue.


Sounder South performs reasonably well. Sounder North does not. You could replace Sounder South with bus service, but it is quite possible that it would cost more. This is not the case with Sounder North, which is clearly flawed, and should be replaced with bus service. Run an express from Mukilteo to Lynnwood every half hour (to coincide with the ferry). Run a bus from Edmonds to Northgate every fifteen minutes. Do that and you get a lot more riders for a lot less money.


In my view, the current version of Sounder South isn’t sustainable or high-quality transit. Sound Transit either needs to decide whether it’s in their long-term vision to purchase the tracks from BNSF and have the ability to invest in an actual transit service rather than continuing the milkrun for a few 9 to 5 commuters. It’s quite possible ridership will rebound, but with BNSF standing in the way I don’t see how any realistic improvements can be made on the corridor without exorbitant costs.


It is probably a lot more expensive to buy the tracks than lease the time. Then you have the cost of running the extra trains. It is commuter rail — it is unlikely that you would get a ton of riders if you ran all day long. Keep in mind that the midday and reverse commute trains get very few riders. The northbound 4:30 and 5:15 trains get about 50 riders a piece — that’s a big money loser, even if you own the tracks.

I don’t know what you are talking about as far as it being a milk run. It is a commuter train — it doesn’t deviate at all. It just follows the tracks.


It is an order of magnitude more expensive to purchase the tracks vs lease. Creating all-day south Sounder is a project comparable to DSTT2 or a Ballard-UW subway (enormous benefit for enormous cost), whereas existing Sounder and the incremental improvements in ST3 are more comparable to a BRT project or funding a handful of express bus routes.


I think the fact that the service plan doesn’t include additional trips for Sounder North suggests that ST staff doesn’t expect ridership to rebound on that line.

Sounder South, of course, is completely different – it has been highly successful, ST expects ridership to rebound and is adding trips accordingly, and Sounder South is a keystone service for Pierce and South King.

Stephen Fesler

To be clear, my comments in this specific thread to Henry were in regards to South Sounder. Of course, not restoring all trips on North Sounder ensures that it won’t rebound anytime soon on the horizon. Total fait accompli.


Fair. But it also likely means ST staff isn’t getting any guidance from the Board that Sounder North is a priority, which means both the technical staff and the politicians don’t see latent demand.