ST3 Transfers Must be Excellent

Convenient transfers can transform a good transit network into a great one. When you don't think twice about switching lines, the network is really doing its job. Unfortunately the designs proposed for ST3's two new massive transfer stations, Westlake and International District (ID) Stations fall well short of that mark. These designs feel like they come from principles steeped in transit is only for commuters" or transit is for other people" rather than what they should be: transit intended to be the primary way everyone gets around the city.

So what makes a good transfer? Some of that is subjective - people don't want to have to cross the street or get rained on in the process, but most of it is objective: How fast can I get to the platform with the other train I need to catch? Anything over three minutes for an average rider is too long: after making it to the platform you still have to wait for the next train. Getting from one line to another has to feel as close to seamless as possible.

ID Station

Of the ID station options presented in the Draft Environmental Impact Statement, only two seem to be worth further discussion: 4th and 5th Avenue shallow." As we noted in our deep stations post, we were disappointed to see that shallow doesn't actually mean shallow - it just means less deep than the absurdly deep options. Sound Transit excluded a real shallow 5th Avenue option from consideration in a previous analysis phase due to construction impacts and considered a shallow 4th station too risky due to proximity to the existing DSTT. Not having either option to discuss or recommend at this phase is a major miss because rider experience matters and shallow stations provide the best rider experience possible.

Of the shallow" options presented, 4th seems to have the most potential. It could be a real transportation hub located between the existing ID station and Sounder/Amrak with direct transfers from buses on 4th Avenue. It also appears to be the hardest to fix for riders without switching to a station design that is as shallow as the existing ID station. Very common transfers from the line that terminates in Tacoma and Ballard are expected to take four minutes. We don't see obvious ways to speed that up but we'll leave those solutions to engineers. Sound Transit estimates that 43% of the daily 34,200 riders will arrive via transfers. That means every minute shaved off transfer times will collectively save these 14,700 riders transferring at this station ten days, every day.

Very common transfers add four minutes to each trip. Sound Transit.

The 5th Avenue shallow" option trades meaningfully slower transfers to Amtrak, Sounder, and buses on 4th Avenue for what should be much faster transfers to the existing Link tunnel. Yet this option is still marred by a slow transfer from the Ballard line to the Redmond Line of 4 minutes, that transfer includes high volume trip pairs like Bellevue to SLU. The fastest Link-to-Link transfer is a big improvement over the 4th Avenue shallow" option at 40 seconds, but that one transfer is the only speed improvement this option offers. It does seem like there are more ways to potentially fix the speed of transfers at this location, but as-is it doesn't perform as well as we'd expect for a transfer station directly adjacent to an existing station.

Slow transfers and pointlessly overbuilt on the right side. Sound Transit.

As with 4th, we have to wonder if a 5th alignment as shallow as the current ID station would look like in terms of trade-offs. In both cases, these options would be almost certainly cheaper, easier, and faster to build. The engineering decision to exclude shallow 4th needs to be reviewed. Using cut and cover to go over an existing tunnel should not be a high risk effort. We've requested more details on this decision including the risk register but have not received a response as of this writing.

Of the options we excluded from contention, the deep 4th and 5th stations were obviously bad, but the diagonal shallow 5th had some meaningful upsides in terms of lessening impacts and construction challenges. Unfortunately, forecasted transfer times are as high as five minutes ten seconds so this option should not be considered.

We generally focus on the long-term interests of transit riders above temporary construction impacts, but a station build-out along 5th is under scrutiny for being another in a long line of projects that have major disruptions in the International District. It's also worth noting that 4th may be a wash with 5th, costs wise, if we consider that the viaduct on 4th needs to be replaced anyways. On the positive side, the station entrances plan for 4th is very good, chock full of redundancy, and seems to consider the best pathways for the most potential use cases. All of that boils down to 4th shallow" being the best option presented so far, but it needs major improvements in order to work for transit riders.

This entrance plan is very good and we like it Sound Transit

Westlake Station
We would love to give the same kind of feedback for Westlake but Sound Transit really only offered up one viable alignment (5th Avenue), and one design option for that alignment. This seems really odd for the expected highest ridership station in the system at nearly 74,000 daily riders. Unfortunately, it looks like transfers will be slow at three or four minutes for the 23,000 daily riders who need to transfer here. Details of what makes this station perform so poorly are hard to discern. The station appears to be deeper and more complex than necessary. Without a more detailed explanation of choices made we can only guess. What we can say is that the station as-designed will be a poor experience for riders. This station needs to be improved with an eye on making transfer trips and access to the surface as fast and seamless for riders as possible.

SODO
There is one more transfer station in ST3 that is often overlooked: SODO station. It's much less complex than the other two mentioned here but is still critically important. Sound Transit expects 79% of the station's 14,600 riders/day to come from transfers. The worse the ID and Westlake stations are, the more important this station will be for riders traveling to or from points South of SODO on the Central and West Seattle lines. Most of the options offered in the alternatives analysis involve a level station, a new car bridge at South Lander, and involve removing the SODO busway. These are bound to be awkward for the pedestrian experience and we should be slow to let go of important transit infrastructure. If preserved, the SODO busway is expected to carry 30-50 buses per hour post Link construction.

The one alternative to at-grade stations offered is termed mixed profile elevated' and appears to have the most promise. This station would be elevated in SODO and would avoid the need for a car-bridge over Lander and the permanent removal of the SODO busway. Transfer speed is slightly better averaged across all potential transfer pairs even though it misses out on the fast (but low volume) cross platform North to Sound transfer. All transfers are at least pretty fast with the slowest options maxing out at 2 minutes. As for SODO station itself, elevated offers what appears to be the most intuitive transfer environment, which can be a big deal when you are unfamiliar with the station and trying to catch a train. This option does retain the gated car and pedestrian crossing at the existing SODO station, but the swing arms have always made this a low conflict crossing for pedestrians and cars.

The biggest knock against the elevated station is price, and a fair portion of that price is the need to knock over a post office building at 4th and Lander. Both the station's western entrance and the adjusted SODO busway require that demolition. The demolition doesn't appear to be necessary if the station moves north and the western entrance is replaced with entrances under the elevated station itself, as with most elevated Link Stations. Moving the station north to avoid a conflict with the Post Office is the same strategy employed by the preferred alternative to avoid the expensive demolition, so it's curious that it wasn't considered for the elevated option. We would like to see Sound Transit consider this alternative.

Removing a Post Office Facility is an expensive and unnecessary feature for SODO mixed profile."

The bottom line is that transfer stations need to be built as well as is physically possible. The success or failure of the transit network hangs in the balance of these decisions. For Westlake, we're disappointed in the lack of options provided by Sound Transit. Westlake is perhaps the most important station in the system and the public has what boils down to a single viable, though somewhat inscrutable, option. Of the options in the International District, a shallow 4th option is the best thing presented by Sound Transit but needs to be much closer to the surface if it is to be successful. We call on Sound Transit to study shallower 4th and 5th options for the ID and if making these stations closer to the surface is deemed impossible, doing everything physically possible to speed up and improve the rider experience.