An Alternative for ST3, With Something for Everyone

When the Sound Transit board next convenes, it will advance a set of light rail and bus expansion projects to go to voters in 2016 as a package known as "ST3." Based on the project list, financial constraints, and desires of local leaders, informed observers assume that this package will include a light rail variation on the aborted monorail "green line" route, running from Ballard to West Seattle via downtown.

Before the final list comes together, let's stretch our minds for a moment and consider an alternate vision, one that's been kicking around here on this blog in the comments section and on Page 2. It comes from several Seattle Subway posts and arguments from from commenter RossB, among others. As we contemplate $15B in new transit spending over the next few decades, this idea is worth one last hearing. I'll call it the peanut butter plan, because it attempts to spread the benefits of light rail and rapid bus lines over as much of the city as possible.

What makes a good high-capacity transit network?

Before I get into the details, let's list some things we know to be true about Seattle public transit:

1. Buses can be time competitive with trains if given their own lanes on freeways or wide, freeway-like arterials. Therefore, in the rare places we have wide, flat, straight roads, we should take exclusive lanes for transit.
2. RapidRide buses work decently well outside of downtown, and could be even better if we gave them exclusive lanes, off-board payment, and got them off downtown streets
3. Rail, in general, ought to get built where geography or density make rapid buses impossible
4. East-West routes in this town generally suck and are great candidates for rail
5. Even after light rail is fully built out, most transit riders will still be using the buses, therefore"
6. Transfers should be great experiences: you can benefit more total riders if you optimize for useful bus-rail and rail-rail transfers

With those principles in mind, let's take a look at the current state of Link light rail and RapidRide lines in the city, including planned Link extensions set to open in a few years. The yellow areas in the map below represent the main choke points for transit, and therefore where the majority of our investment should occur: crossing the ship canal, downtown, and the entrance ramps to the West Seattle bridge.

Current and Planned Link/RapidRide Routes

Now let's look at the light rail expansion Sound Transit is likely to propose next month, which I'll call the Green Line (yes, I realize I'm using blue on the map). It would replace RapidRide D from Ballard into downtown via Interbay, with a stop in South Lake Union, a second downtown tunnel, and a line to West Seattle terminating at Alaska Junction (ST may choose Delridge over the Junction, but either way there won't be enough money to go too deep into West Seattle). Based on Sound Transit's corridor studies and other documents, we can guess the cost of the Green Line at around $6-7B.

Likely "Green Line" proposal

To be clear, the Green Line would be amazing; I think most people reading this article will vote for it in a heartbeat. But it has some downsides. It's very downtown-centric, for one. Getting East-West across North Seattle would still be a slow ride on the 44 or a circuitous route via downtown. Given the geography and lack of fast roads between Ballard and UW, there is no chance of ever building a fast bus to make that East-West connection. By contrast, most of 15th Ave W to Ballard and the West Seattle Bridge contains fast freeway or quasi-freeway right-of-way and relatively little cross-traffic, where buses can move fast if given their own lanes (see principle #1 above).

Secondly, the Green Line leaves several neighborhoods with no transit improvement at all. Belltown, a dense residential neighborhood, gets skipped to serve South Lake Union. That may be a good trade, but choosing one means avoiding the other. It doesn't do much for relatively dense and growing North end neighborhoods like Wallingford and Fremont. It means choosing either Delridge or the Junction, but not both.

The peanut butter plan, described below, addresses these concerns.

The Plan

The peanut butter plan combines several projects:

1. A second downtown transit tunnel for buses (the WSTT) speeds up Westside buses (like the C, D, E, 120, and others) through downtown, where space is congested and they need it the most. Since it's a tunnel, there's no chance that downtown congestion will ever affect the buses. Travel times to downtown from Ballard, Interbay, and Alaska Junction should be competitive with rail.
2. A 3-mile light rail extension from Ballard to the UW, which provides the vital East-West connection. Somewhat surprisingly, thanks to the magic of rail, a trip from Ballard to Downtown via UW is about as fast as Ballard to Downtown via Interbay, so Ballard riders could get Downtown nearly as quickly as via the Green Line.
3. All-day BRT lanes along 15th Ave and the West Seattle Bridge, which doesn't cost much but requires willingness to ignore or buy off certain interest groups.
4. A new, wider Ballard Bridge with bus, pedestrian, and bike lanes
5. Sound Transit-level BRT along the both Junction/35th Ave SW and Delridge Way corridors, all the way south to White Center or possibly Burien (if South King funding permits it), taking parts of ST's A4 and B2 BRT alternatives. To be super clear, this isn't just painted buses, it's "real" BRT, with mostly exclusive lanes on both corridors. For perspective, the Seattle Transit Master Plan envisions a combined $9 million in improvements to these corridors. Sound Transit assumes $2 billion for these corridors (details below), several orders of magnitude more investment.

Peanut Butter plan: delicious!

The result is a rapid transit expansion that brings serious speed and reliability improvements to just about every neighborhood in Seattle, while opening up a new East-West connection for non-downtown trips. Riders of express buses from places like Broadview, Phinney, and Alki would see their commutes shortened thanks to the new bus tunnel and a one-seat ride into downtown.

With this plan, we don't have to choose between Belltown and South Lake Union, we can serve both. We don't have to choose between Delridge and the Junction, we can serve both. We don't have to choose between Wallingford, Fremont, and Ballard, we can serve all three. Finally, it doesn't preclude the Green Line: the WSTT could still be converted to rail at a later date.

Political and Financial Costs

The peanut butter plan would cost about $6B, the low end of our Green Line estimate. That includes $2B for the WSTT, $1.9B for BRT on both 35th and Delridge and across the West Seattle Bridge, $2B for Ballard-UW light rail, and $100M for a new Ballard Bridge. You can view the math here, but keep in mind it's an informed guess.

More riders for less cost? What's not to like? Well, you don't get something for nothing. Making the peanut butter plan a reality would require a huge political commitment to fighting for every inch of bus-exclusive lanes along the Western half of the city. Before this month, I would have considered that an impossible task. After seeing how much pushback SDOT is getting for watering down Madison BRT, though, I'm slightly more optimistic.

Additionally, the Green Line saves operational costs by forcing West Seattle riders to transfer from several buses to a single, high-capacity train going into downtown. The peanut butter plan, by contrast, would give more West Seattlites a one-seat commute, but would incur higher operational costs by sending more buses all the way into downtown.

Lastly, technical merits aside, there's an important electoral question. ST3 needs to win big in Seattle to offset potential losses in other parts of the Sound Transit region. The plan can't just serve riders, it needs to win votes. To that end, any plan that doesn't string steel tracks across the Duwamish river is taking a political risk of losing votes in West Seattle. And not without reason: years of overloaded RapidRide buses slogging through various downtown and West Seattle chokepoints may have permanently soured West Seattle commuters on buses.

With the vote in 2016 we're going to lock in another 30 years or so of transit spending and funding. Let's not let pre-conceived notions prevent us from seeing the full range of alternatives.