by Dale Menchhofer
tl;dr: This post proposes a new option for the Interbay – Ballard segment of the West Seattle – Ballard light rail project that is measurably and significantly better than any of the remaining official options. The major components are (1) an aerial bridge over the BNSF rail yard, (2) an optional station at Fisherman’s Terminal, (3) a shorter tunnel under Salmon Bay, and (4) a station at 20th Ave NW and NW Market St.
This option has the highest possible value—retaining the high quality of a tunnel, but with significantly higher ridership, and at a competitive cost. In fact, it has a lower capital cost per rider than any of the official options. It has opportunities to turn Port of Seattle and BNSF into 3rd party funding sources, instead of potential adversaries. In spite of its superior characteristics, the only hope it has of becoming the preferred alignment is if enough of you support it in ‘scoping’ comments submitted to Sound Transit. Find handy links to do that at the end of the post.
Intro: why this option is optimal
The best possible ridership puts the station location in the center of the urban village, at 20th Avenue and Market Street. This location is closest to all of the current density, and closest to potential future development.
This option uses the shortest tunnel possible for crossing the ship canal of any practical location. It is about 10-12 % shorter than the 14th or 15th Avenue tunnel options. It is 28% shorter than the “BNSF West/20th Tunnel” option rejected in Level 1 scoping. The shorter the tunnel, the less costly the option. The limiting factors preventing the tunnel from being even shorter are (1) a maximum 5% grade and (2) allowance of 25 feet between the top of the tunnel and the bottom of the ship canal.
In order to reach the shortest possible tunnel, it is necessary to bridge over the BNSF rail yard. I acknowledge that would generally be unwise, but in a later section, I explain why this route is different; why it is uniquely feasible.
There is no practical route using a high fixed bridge to reach a station on 20th Avenue, because of impacts on the legally protected Ballard Landmark District. A tunnel is the only way to do it that does not sacrifice quality.
This option has two additional advantages. It has a net reduction in properties taken, thereby reducing cost further. By eliminating a curve, the Interbay station can actually be at Dravus Street, a better location.
14th and 15th Avenue options have significant drawbacks
Without this option, the option most likely to be chosen as the preferred alignment is the 14th high-bridge option. The simple reason is that it would be the only option left after discarding the drawbridge option, which the public has loudly denounced, and the tunnel options, which add too little value for the money.
A station on 14th would be disastrous for ridership. It would invite derision by critics as a “line to nowhere.” It would jeopardize the chances for passage of any ST4 proposal.
Avoiding complete disaster for the high-bridge option would require finding some way to get the station located on 15th instead of 14thh. That would likely involve taking a LOT of expensive properties. Adding still more expense, a station at 15th requires 3 pedestrian bridges to function reasonably well. One bridge would have to cross Market east of 15th for the sake of transit connections. To keep the walkshed from being severely stunted, a bridge would be required across 15th, and a third across Market west of 15th. A station on 14th does not need one for transit connections, but does need the latter two, in order for the walkshed to extend anywhere beyond 15th.
Possible paths to selecting this better option as the preferred alignment
- Because this 20th Avenue option costs less than the existing tunnel options, and would have substantially more ridership, making a case on the basis of lowest cost per rider might be just enough to win approval.
- The second path to success emphasizes avoiding a poorly performing station on 14th. There is a reasonable chance that the added costs necessary to scoot the line over from 14th to a station on 15th, plus the costs of adding pedestrian bridges, might add up to a higher total cost than a better 20th Avenue option.
- If two options are advanced as preferred, as ST staff have indicated is a possibility, then one would be a cheaper option, and the other would be contingent on securing 3rd party funding. In that event, we would want the more expensive option to perform better than what a station at 15th can do. If the only path to this better option depends on 3rd party funding, then this option has a realistic way to get Port of Seattle to become that partner. This route has an optional added station at Fishermen’s Terminal which could supply the incentive and justification they would need. (It would perform reasonably well too, with bus and bicycle connections, and a respectable amount of employment in the vicinity.)
Re-examining the “West of BNSF/20th/Tunnel” option
The only prior option proposing a station on 20th was discarded in Level 1 scoping. The reasons are summarized on page 50 of this document. The principal reason was due to the high cost of a longer tunnel. I have already explained that this new option has the shortest possible tunnel, so that reason does not apply.
ST says that the 20th station would require “construction and displacement within Ballard core.” The map on page 50 shows the station spanning Market Street, which implies an open pit to construct the station, disrupting busy Market Street. In contrast, the option I am presenting puts the station immediately north of Market. Since the tunnel would be bored under Market, this station placement avoids disruption of Market Street. (Access to station entrances on the south side of Market would be mined.) This station placement also brings the platform about 10 feet closer to the surface and slightly improves the walkshed.
20th is a far quieter street than Market, so a cut-and-cover technique ought to be sufficient, especially since there are standard techniques to keep one side of the street open at all times, and to install a temporary lid as soon as possible. If these techniques are not deemed sufficient, then the station and tail track can be mined. That is more expensive, but if it is the only way to get a better station location, so be it.
The bubble chart on page 49 identifies two more criteria ranked as “lower Performance.” I believe “Engineering Constraints” expresses concern that the right of way on 20th might be too narrow to allow uninterrupted sidewalk access while excavating the full width of a station. If so, the solution is once again to mine the station, although cheaper conventional techniques could still be used for the narrower tail track.
“ST Long Range Plan Consistency” apparently means that expanding the line north would require expensive tunneling to get to daylight on 15th. That is so, but at least it has a clear path to do it. In contrast, there is no good way to extend north from an elevated station on 14th. As for extending north from an elevated station on 15th, ST staff has said that there is enough room to squeeze past the new building still under construction, but since the available area is narrower than that for the representative alignment over on Elliott Avenue, call me skeptical. Regarding inability to turn the line toward UW, Ballard-UW is better done as an intersecting line, not as an extension.
20th Avenue is centered on the urban village
Census tract 47 extends from 8th Avenue to 24th Avenue, and from 60th Street to the Ship Canal. In 2018, the area of the tract west of 15th had 2 ½ times more population than east of 15th. And it has been pulling away. In percentage terms, it grew 4 times as much from 2010-2018 (86.6% vs. 21.8%), and 3¾ as much in the prior decade.
A 5 minute walkshed for 20th captures most of the taller buildings in the area, while 15th reaches a small fraction, and 14th reaches only a handful of buildings. A 10 minute walkshed for 20th gets to all except far-flung buildings at or beyond the corners of the urban village. The 10 minute walkshed for 15th barely gets to 60%. 14th doesn’t even get to 20%.
Land uses other than housing also favor 20th. The cinema alone generates 300 trips every weekend night. The hospital alone generates about 500 trips daily, for patient visitation and outpatient purposes, that is, not counting employee commuting. Both of these are easily within the walkshed of 20th, but are outside the 5 minute walkshed of 15th.
Anyone at all familiar with the neighborhood knows that for every single retail store, restaurant, coffee house, bar, nightlife venue, or professional service business in the walkshed of 15th, there are approximately 10 examples of them in the walkshed of 20th. About all that 14th can claim are 3 brewpubs, a set of hair salons, and a thin veneer of low-rise apartments bordering 14th or Market.
Sound Transit found (p. 29) that a station on 17th generally had a couple thousand more daily riders than one on 15th. Given the demographics and land use patterns I’ve described, this seems like an understatement. Furthermore, a station on 20th should amplify the trend.
14th would get few riders except those who transfer from a bus. 20th would get all of those, plus perhaps almost as many on foot. In other words, the ridership for a station at 20th may well be close to double that of a station at 14th. 15th would be somewhere in between, but closer to 14th. If we were to rank ridership using the bubble chart method, 14th would deserve an empty circle, 15th a half circle, and 20th a complete, filled-in circle.
A huge swath on the south side of the walksheds for both 14th and 15th is consumed by land uses that generate little pedestrian traffic: auto services, contractors with trucks heading to jobsites, and manufacturing. Even after construction impacts are past, a station at 14th or 15th would threaten the long-term viability of those businesses.
In contrast, a station at 20th would be surrounded by compatible land uses: numerous tall apartments and condos, a denser employment base, retail, hospital, professional services, restaurants, bars, coffee houses, entertainment and nightlife. Once a station is built near those, increased foot traffic will help them thrive.
Even if the boundary of the urban village is extended east, as has been proposed, and even if the current single family dwellings were all replaced by dense redevelopment, these stations would still underperform! A large fraction of the walkshed would still lie outside the upzoned area, and would still have incompatible land uses. Also, a station still close to the edge of the density can never catch up to a station in the center of it.
The cycle time of traffic lights at the intersection at 15th and Market is inherently lengthy, due to high vehicular volumes and left turn signals for every direction. Consequently, it takes up to 2 ½ minutes to cross in any direction. Crossing in both directions takes up to 3 minutes. The average is a bit less, but I used the maximum in determining the walkshed boundaries, for two reasons. First, people are annoyed by long waits more than they notice shorter waits, and perception matters. Second, in order to arrive on time, any rational traveler has to plan for the longest likely travel time.
Since 5 minutes is the average time for a ¼ mile walk, these lengthy delays cut the southwest quadrant of the walkshed down to 2 ½ blocks, and the northwest quadrant to a meager 2 blocks.
The location on 20th works better for buses in ways that are not obvious. We should assume that existing bus routes 17, 18, and D would terminate wherever the station is located, consistent with the Metro Connects 2040 vision.
Given that, a station at 14th or 15th wastes bus service hours for routes 17, 18 and 40, but a station at 20th does not. For the RapidRide D, 20th is a better new terminus than 15th for all the same reasons as for light rail. Ballard is a significant destination. It is better to not have the RapidRide D stop ¼ mile short.
Finally, 20th works as well as 14th for bus-rail transfers without crossing a street, and better than 15th.
Compatibility with BNSF operations
This route is unique, in that it appears to be the only route which can bridge over the BNSF rail yard without interfering with current operations or potential future changes. To explain why, as succinctly as possible, understand that horizontal and vertical access to trains is essential at sidings, not at switches (south end), nor by the yard office (north end). Also, significant restructuring of the track layout in the future is unlikely, because the current layout already maximizes use of the available land.
Like the existing options using Thorndyke, this route would be on the east side of BNSF to Dravus. But north of Dravus, it would head straight to the conveniently diagonal stretch of Emerson Place. To avoid placement next to sidings (or storage areas), support columns would be just east of the gravel maintenance path clearly visible in satellite images. But then, as it nears the yard office (attached to the old roundhouse), support columns would be on the west side of the path. Adjacent to the yard office, to keep columns out of the way of all traffic, a column could be next to a landscaped island, and others immediately north and south of the small parking lot, in the no parking zones.
The real estate arm of BNSF may have long-range plans to lid over the less used northeast wing of the yard, in order to derive new revenue from what could become several blocks worth of new urban density. If they have any interest in such a scheme, BNSF could become an additional 3rd party funding source. The optional station near Fishermen’s Terminal would be well placed to serve the resulting new neighborhood.
Compatibility with Fishermen’s Terminal
Even though this route is adjacent to Fishermen’s terminal, it avoids any conflict with port operations by skirting clear of the waterfront. Continuing north after bridging over BNSF, the route would cross Emerson Place, to run on the north side of the street. This avoids power lines on the south side. The parking lot for Fishermen’s Terminal provides a buffer area, maintaining sufficient distance from any possible conflict. The route then crosses above 21st Avenue and uses a convenient hill to transition to a tunnel portal in the vicinity of a gravel parking lot just north of a gas station. Running the route under 22nd avoids the waterfront, and happens to add just enough distance for the tunnel to get under the ship canal.
If I have succeeded in explaining this option, it should be apparent that it is far better than any other option. In spite of that, it has virtually no chance of becoming reality, unless enough of you submit your comments into the record in support of it. Please do that before the April 2 deadline, either online at https://wsblink.participate.online/ or by email to email@example.com. And please also ask your friends, who might not read this blog, to do the same. It is no slam-dunk, but we owe it to future generations to try. It is allowed by the formal process up until the deadline, but not afterwards. This is our last chance.
Dale Menchhofer has been working for 35 years, as an engaged citizen, to improve non-automotive transportation. He is employed as a data-centric software developer.