New downtown tunnel for light rail, current DSTT for buses and streetcars

Second Downtown Seattle Transit Tunnel (Graphic: Jason Lu, Base map: Shane Valle)
Second Downtown Seattle Transit Tunnel (Graphic: Jason Lu, Base map: Shane Valle)

Both transit advocates and politicians have been discussing the idea of a second downtown transit tunnel through Seattle, which would act as the foundation for future rail service to Ballard and West Seattle. Seattle Subway’s proposal currently looks like this and seeks to address a few issues:

  • Mitigates the closing (for buses) of the current Downtown Seattle Transit Tunnel by building the tunnel initially for buses
  • Provides capacity enhancements in the downtown core
  • Can provide exclusive lanes for buses heading to West Seattle and Ballard

The proposed tunnel could also have a few drawbacks:

  • Costs of unused railway infrastructure: If the tunnel were to be built initially with railway infrastructure (tracks, power and communications) as Seattle Subway suggests, these would still require some form of maintenance even if they were not being used. These infrastructure components don’t stand still over time, and will have an aging effect. No one really knows how long it would take for rail services to begin, but it would be a waste to maintain infrastructure that is not being used.
  • There are only 3 stations (Westlake, Madison and International District), fewer than the current DSTT. Although this would give a direct connection to Madison BRT, it would also mean that buses serving the new tunnel have farther stop spacing and potentially shorter travel times than light rail in the DSTT, the opposite of what it should be.
  • Conversion to rail could be a slow process due to institutional and political inertia, which may result in another DSTT situation where buses are “phased out”. The lesson to be learned from the DSTT, is that joint-operations is difficult and results in unreliable service for every mode, even six years into operations.
  • Alignment constraint in the current DSTT are not addressed, such as the Westlake or Chinatown curves

In an attempt to explore how these issues could be resolved, I’ve created another proposal, which is a tunnel on 4th Ave that will accommodate all light rail services from the beginning and in the future. The current DSTT will then serve buses (again) and potentially streetcars. The “Westlake curve” will also be removed, allowing higher speeds in the tunnel. I’ve listed a few key advantages of this proposal.

Continue reading New downtown tunnel for light rail, current DSTT for buses and streetcars


Transit objectives should be defined before its infrastructure

As Seattle’s transit advocates, we often like to brainstorm about transit infrastructure because it generates discussions. It helps define what the region wants, and these discussions often drive politics. Light rail connections, BRT, and a second downtown tunnel are just some highlights of an ever-growing wish-list.

However, our focus on modes and infrastructure also leads us to overlook the actual objectives of these transit investments. We ask ourselves whether we want light rail and BRT, but rarely do we emphasize, “How quick and reliable should the system to be?” or “What is this system trying to accomplish?”

As a result, transit advocates are often surprised by operational deficiencies late in the process, leading to reactions like this:

“We have supported RapidRide and BRT from the beginning but Metro and the Council have let ‘BRT creep’ and politics take over, not what is best for riders. When RapidRide C and D lines open on October 1st we’ll have a glorified shiny new bus that is slower than existing service.” – STB

Part of the reason is because specific objectives are not clearly defined before transit is built. There were never defined travel times or reliability requirements from the beginning. We simply said “Build BRT” and assumed that everything would work out. As a result, decision makers have leeway to push for more infill stations to satisfy a few constituents, because why not? There was no legal requirement for what the actual travel time between A and B should have been. It’s easy to backtrack and modify service objectives that were never well-defined in the first place.

Continue reading Transit objectives should be defined before its infrastructure

Technical challenges of light rail versus conventional rail

Westlake Station (Photo: Jason Lu)
Westlake Station (Photo: Jason Lu)

A few days ago, I posted on why light rail vehicles may not contain the performance necessary for regional transport (i.e. services that bridge suburban rail and low-end intercity rail). A brief overview of technical limitations was presented, but in order to keep the article short, the technical issues were simplified and details were omitted.

If you’re the type who enjoys a discussion about some technical challenges unique to light rail, here’s your article. We’ll discuss design characteristics that separates light rail from conventional heavy rail, focusing mainly on wheel-rail interactions. Then we’ll touch a bit on why higher vehicle performance is more complicated than just asking the vehicle manufacturer to tweak their trains for a higher design speed.

Continue reading Technical challenges of light rail versus conventional rail

Seattle’s light rail is being made a one-size-fits-all solution that doesn’t (Part 2)

Othello Station (Photo: Jason Lu)
Othello Station (Photo: Jason Lu)

In part 1, we discussed how the limitations of our light rail system may impact its performance as a regional service. Now, we will highlight some potential issues within cities that we may face when our light rail capacity is adapted to serve high-demand suburban services.

Light rail’s need to provide high capacity and reliable mobility for the region is supported by its infrastructure. When the infrastructure means “surface running”, such as on MLK, high capacity (i.e. longer trains) is accommodated by large stations and reliability is provided by long stretches of track with uninterrupted travel. Although this means that mobility to and from the neighborhood is improved (regional mobility), accessibility within the neighborhood may be compromised.

Continue reading Seattle’s light rail is being made a one-size-fits-all solution that doesn’t (Part 2)

Seattle’s light rail is being made a one-size-fits-all solution that doesn’t (Part 1)

Tukwila International Blvd Station (Photo: Jason Lu)
Tukwila International Blvd Station (Photo: Jason Lu)

With light rail expansion and planning well on its way, things look positive for rail transport in the Puget Sound Region. The momentum and demand for rail-based transport in the region appears higher than ever, with residents beginning to realize that our current transport network is simply inadequate for the growth rate in this region. When a single fish truck can bring the region to hours of standstill, transport alternatives cannot come soon enough.

However, as with every major project, there is always a time to step back and once again look at the big picture. What type of transport objectives are we trying to accomplish? What kind of connections and services do we need?

But here is the biggest question that we need to answer before Sound Transit 3: What exactly are we building right now?

The simple answer is, of course, light rail. The more complicated answer is that we are building a regional light rail network.

And that could be a problem, because light rail vehicle technology is not intended for regional services. If Sound Transit pushes these vehicles to compete with cars between Everett and Seattle, or Tacoma and Seattle, it will have to find a delicate compromise between competitive travel times and travel time reliability. Let’s discuss why.

Continue reading Seattle’s light rail is being made a one-size-fits-all solution that doesn’t (Part 1)

The Planner as a Technician and Activist

The planner is at once a technician and an activist. These modes exist in constant tension within every planner, the balance between the two shifting depending on the degree to which the planner’s position permits him to express both modes. This writeup will focus on the role of the planner operating within a traditional municipal planning body and how a planner can skillfully balance both tendencies.

But first, what’s a planner for (broadly)

The planner receives information from and provides information to the community he works in. With the information he receives, the planner assesses trends, problems and opportunities. He provides the results of his assessment to the community. On this basis, the community may choose to pursue action, a choice relayed back to the planner whose role it is to help the community take action, and on and on the dialogue goes. The planner further serves the community by making the information he collects and generates accessible to everyone while encouraging members to exchange thoughts with one another and providing forums to do so.

The planner as a technician

The municipal planner also serves another master: the leader of the municipal body, often an elected citizen or body of citizens. It is the planner’s role to assist newly-elected leaders to accomplish what they said they would when they ran for office. This involves knowing the techniques of planning well enough to employ them for the official’s use.

Elected officials are not looking for planners with agendas; the officials were elected to implement theirs. In the words of a Portland Metro area mayor, “if you want to refuse to do something, be prepared to polish off your résumé.” Elected officials are looking for planners to provide them feedback on feasibility, to clarify complex language, to exchange information with the public, and to speak up when the official might be getting herself into trouble, either with the community or the law, both of which the planner must be very familiar.

The planner as an activist

In opposition to functioning subordinate to a political administration behaving as though there is nothing beyond the next two to six years (because often, for them there is not), planners must look out far beyond the term of the current electeds to protect the longterm interests of the community. Planners are uniquely situated to perform this task, being employees with no political expiration date, who consistently interact with all parts of the community served, who are aware of the flexibility afforded by planning codes, and who are attuned to persistent social, economic, and environmental issues.


Planners should take every opportunity to make the municipality government work for its community, even and especially when community members, present and future, are not being well served by the policies pedaled by electeds. The planner operates in an ethical grey area whether he choses to be an activist or not: by choosing to function as a cog in a machine, he is letting the status quo persist, often meaning issues of equity and sustainability go unaddressed; if he chooses to act, then some of what he sees as wrongs might be righted.

The skillful municipal planner keeps his job while also advancing the causes of his community members, despite a revolving cast of political characters. But even community members can be short-sighted, requiring the planner to sometimes act unilaterally, using his own knowledge and reasoning to account for voices not heard and for people not in the room (future generations, the environment, kids, elderly, the impacted but unaware). There are no guidelines for these situations. Planners should learn to inhabit and be comfortable in this grey area, where what is Good and True are ever-changing, and where the promotion and search for what are Good and True never cease.

Seattle area bus route passenger load section charts

I threw together a couple of charts to visualize how passengers have been using some of the routes that may be impacted by the U-link bus restructure. The data is hosted on Metro’s “For Transit Geeks” section of their U-Link bus network restructure proposal.

Here’s Route 48:

01 Load section charts-02

Notice how the passengers accumulate approaching the University District (45th St/15th or 50th St/15th, depending on direction) and begin to diminish when moving away from it. Also notice the higher passenger turnover when compared to the long haul 255 and 545 below (vertical comparison between colored area and grey area).

Here’s Route 255:

And here’s Route 545:

01 Load section charts-04

Both the 255 and 545 accumulate riders at a rapid pace until reaching the 92nd Av/SR 520 stop when going toward Seattle, with a few more getting off at Montlake than getting on. On the return trips, the 545 loses more than half of its load at the NE 40th and 51st St stops while the load on the 255 trails off somewhat steadily until the end.

Metro uses slightly different stops to define segments depending on which way the bus is traveling (inbound vs outbound); take heed when comparing the charts for the two directions. This visualization might be a lot more interesting and useful with break downs by time of day, by trip, or even by stop, but it doesn’t look like Metro provides that level of data. Bear in mind this is data for the whole day and is really only useful from that perspective.

An improvement I can already see is running these again on the same scale y-axis to get a better comparison between the routes; my intent here was simply to look at loading behavior across individual routes.