Page Two articles are from our reader community.


The Downtown Seattle Transit Tunnel has improved transit in Seattle more than any other project. Long before it served trains, it served buses (and still does). Thousands of buses have gone through it, saving passengers thousands of hours in travel time. Now it is an essential part of light rail — by far the most important part. It wasn’t cheap to build, but compared to the rest of the system (such as the Beacon Hill tunnel, the surface rail on Rainier Valley or the elevated rail to the airport) it is a tremendous value.


At a point in the not too distant future, the tunnel formerly known as a “bus tunnel” will only serve light rail. This is a good thing, but it means that some buses, especially those from the south, will be forced to the surface through downtown or rerouted elsewhere. At the same time, we are in the midst of planning for high speed transit from Ballard to downtown and West Seattle to downtown. We should build a new tunnel to address all of these issues.


I propose a new transit tunnel through downtown that will support both buses and light rail. From the southern end, it would start (and connect seamlessly) with the SoDo busway. In the middle, it would parallel the existing tunnel at least in part, allowing for easy transfers along the route. The northern route is trickier. The big question is whether to pay the extra money to include Queen Anne, and if so, which parts of Queen Anne. Corridor A includes stops on upper and lower Queen Anne. This wouldn’t be cheap, but it would certainly be popular. Corridor B only include a lower Queen Anne stop, and saves money in the process. Arguably the best value would be a modified Corridor C. This would be significantly cheaper, especially if much of the tunneling work could be done as cut-and-cover (just as the original tunnel was built as a mix of cut-and-cover and boring). I really don’t have a strong opinion on which northern route is best, as the costs are so sketchy. In general I would say that each proposal has merit, and that each route would be a good value. It is simply a case of how much extra we want to spend for the extra ridership. This decision (the exact northern route) does not alter the basic proposal — a second, mixed use tunnel would be a great value for the city.

The Southern End

Bus riders who live or travel south of downtown Seattle would benefit greatly by this tunnel. The SoDo busway is a great asset for buses. It connects freeways in the area with downtown (through the existing tunnel). With relatively inexpensive changes, the buses could connect from the south to downtown in a fast, exclusive way. WSDOT is currently improving the HOV lanes and has plans for more. Fairly soon, there will be HOV lanes continuously from Tacoma to Seattle. The state has also proposed adding a ramp to better connect I-5 to the SoDo busway (they don’t have a project website, but it is the second proposal listed here). This would enable a rider to go from Tacoma to downtown Seattle in an exclusive lane the entire way. Similar changes could be done for West Seattle. Parts of the West Seattle freeway are already HOV only, but more could be done on the freeway itself, as well as to connect the freeway to the busway. This isn’t cheap, but it is a lot less expensive than new light rail because much of the work has been done, and buses can travel a more steep grade than trains. For a lot less than the cost of the cheapest light rail line to West Seattle  (serving only one station) you could add miles of exclusive lanes and  ramps. With the money left over, you could fund countless improvements to the buses in the neighborhoods (exclusive lanes, traffic light priority, offsite boarding, etc.).

Speed Now and More Capacity Later

Unlike the existing tunnel, this new tunnel could be designed for off board payment from the very beginning. It would also be designed to handle buses and trains the day it opened. Like the transit tunnel, it could accommodate future rail expansion. If West Seattle ever gets populated enough to justify the extra capacity and cost of light rail, then the tunnel could handle it.


One alternative is to build light rail from West Seattle to this tunnel immediately. I could spend a lot of time explaining why I think this is a bad value, but consider, just for a second, how exactly that would be better for folks in West Seattle. The population in West Seattle, as in much of Seattle, is spread out. This means that you wouldn’t get very high ridership unless you funnel people (via buses) to the station. There is nothing wrong with that — it plays a large part in why I think this route makes so much sense. But in the case of West Seattle, it makes a lot less sense. Buses in the area can, in many cases, get to the freeway faster than they can get to a subway station in West Seattle (assuming there is only one subway line). This means that there would not only be a transfer penalty for most riders, but little to no time savings while riding. The transfer penalty could be substantial — Sound Transit expects headways on the West Seattle line of ten minutes (and that is during rush hour). It is important to remember that buses and light rail travel at about the same speed. The time savings come from grade separation, not vehicle capability. For this corridor, it is a lot cheaper to build that grade separation for buses, not rail. Rail is still better from a capacity standpoint, but at this point, it simply isn’t needed for this area.

Buses from Tacoma could simply use one of the other stations (such as the one in Tukwila). But that would cost riders a lot of time. Unfortunately, unlike the rest of the system, the train moves very slowly, and very infrequently between Tukwila and Seattle. Even transferring riders from Renton to a station at Rainier Beach would cost riders a substantial amount of time.

Another alternative is to use the SoDo station as the endpoint for buses. To do that, you would need to build a bus station there to allow buses to turn around. For this type of system to work, you would need very frequent rail service (think Toronto, not Washington D. C.). Unfortunately, I don’t think this will ever happen. Trains from the south will never be able to travel very frequently through the Rainier Valley. Sound Transit could add a turnback station in the SoDo area and send additional trains there, but there are significant limitations with that approach. Headways are limited in our central core, and some of those trains will branch off to the east side. Simply put, I don’t think we will be able to have the kind of frequency from SoDo to make such a transfer painless. The transfer would not be as bad as the one in West Seattle, but it wouldn’t be good, either.

Another approach would be to build a short tunnel from the southern entrance of the existing tunnel to the International District station. That would allow someone to make one transfer to any other part of the system. Furthermore, this puts it much closer to the heart of downtown. Even if SoDo becomes more popular, I doubt it will never be as popular as the area surrounding the International District. If not for the work being considered for Ballard, this would make a lot of sense.


As Bruce Nourish mentioned, the most important part of the Ballard to downtown line is from Mercer to downtown. The rest of the route can be done on the surface, with little time penalty (less than a minute). But through downtown, you need a tunnel. It makes sense to run this tunnel as far south as the SoDo busway, and have the southern end serve buses not only from West Seattle, but from Tacoma, Renton and other areas.

50 Replies to “Let’s Build Another Transit Tunnel”

  1. If Link is build between Downtown and Ballard or Downtown and West Seattle there will be a second transit tunnel in Downtown.

    The first question is is it worth building the second tunnel to accommodate bus operations? What is the additional cost? What operational compromises are forced by designing for mixed operation rather than an exclusive light rail tunnel?

    If ST3 is on a fast track to approval, it contains lines serving Ballard and West Seattle, and there is some improved service to Fremont (Link or exclusive lane streetcar) then I don’t think accommodating buses is necessarily worth the bother.

    On the other hand if ST3 isn’t going to be big enough to have a Westside line or looks to be delayed I think this is a very worthwhile project.

    While expensive this is something that might be possible with just city and county funds, especially if the monorail tax authority can be used to build it.

    The question of the northern portal is an interesting one. Obviously this is easier if you are concurrently planning/building a Downtown/Ballard line at the same time. Simply place the northern portal at the best location possible to provide access from Aurora and RR E. One thought would be to see if the current Battery Street Tunnel ROW can be used to access the new DSTT.

    If the tunnel is stand-alone then you would need a west portal. The trick here is to do this in such a way that it doesn’t preclude future rail options but doesn’t a large amount of tunnel not used by rail.

    1. That’s the north portal I was going to propose. The new 99 tunnel shouldn’t require demolishing this one, and it provides many options for continuing north, whether along 99 or turning left or right on Thomas or Harrison, or you may also have a route to Ballard via the Elliott/Western entrance.

      1. The thought of an additional northern portal crossed my mind as well. I decided not to complicate things by adding that idea to my post. My basic argument is that while light rail from West Seattle would be nice, it would be much more cost effective and rewarding for everyone if we simply funnel buses from the south end to a tunnel which serves trains from Ballard (and put some of the extra money into other improvements).

        But I agree, an additional northern portal makes sense. There are a few options, as I see it:

        1) Add entrances and exits on the surface. This wouldn’t be that expensive, and would allow a number of buses from the area to move through town much more quickly.

        2) Connect it to 99. This would make for a very fast and reliable “E Line”. You still have the problem of Aurora, though. They have BRT lanes there, but they are shared by drivers turning right, which slows things down. Overcoming that problem would be expensive. So, while a connection to Aurora would make the bus line better, it wouldn’t be cheap, and it wouldn’t be easy to make it great (as great as BRT from West Seattle could easily be).

        3) Dig a branch tunnel to South Lake Union. This would become the terminus for all south end buses (the tunnel would have a turnaround in South Lake Union). I don’t think this would be horribly expensive. For example, from 2nd and Battery to Westlake and Harrison is only about a kilometer. Not to say a tunnel is cheap, but this would be a huge improvement for transit in this (now every) popular area.

        I would consider all of these options nice, but they all add money (although the first one is dirt cheap). My guess is, though, that we could have all of them for the cost of West Seattle light rail.

      2. The thing is if this I’d being built (or even just designed) concurrently with a Downtown-Ballard Link line then any bus portal serving 15th NW is fairly redundant as Link would be expected to supplant any bus lines other than Magnolia.

        Other than 15th NW the other corridors that scream for better transit access from the north are Aurora, Dexter, and Westlake. With the exception of rapid streetcar on Westlake none of these are planned for upgrades to rail any time soon.

        A big question here is the fate of the 99 tunnel project. If it continues forward then the Battery street tunnel is largely redundant. If access ramps to a new transit tunnel can be fitted then it gives a ready-made ROW for accessing Aurora, Dexter, and SLU.

    2. A Westside Transit tunnel (via 2nd or 4th) would be a great idea if the legislature fails to get Sound Transit funding authority for ST3. Transit advocates should get some large capital project on the ballot for 2016 even if is not ST3 like we currently hope.

    3. I think you guys might be confused (sorry about that). I am proposing THIS as part of ST3. Basically, I would have the following for ST3:

      1) Ballard to UW underground rail (
      2) Ballard to Downtown rail, connecting to this tunnel. *
      3) BRT from West Seattle (and other areas) to this tunnel. **

      That’s it. That is what I would have (for Seattle) for ST3. I realize I only made a short and sweet argument for why I think West Seattle light rail isn’t worth it, so I will try and expand it later.

      * You could make the argument that with Ballard to UW rail and the tunnel, we don’t need rail from Ballard to downtown. However, Sound Transit doesn’t think so. None of their final proposals included BRT. On the hand, many of the West Seattle proposals list BRT.

      ** I hesitate to call this BRT, when what I really want to say is “bus improvements”. This includes the following:

      1) As much grade separation as a typical light rail system (like ours).
      2) Signal priority on the non-grade separated pieces (like our light rail).
      3) Off board payment.

  2. On the issue of time savings I’ve noticed that dwell times for light rail are shorter than buses due to the number of doors, and dramatically shorter in the case of disabled boarding so there would be somewhat slower and less reliable service by busses.

    Also I would recommend perusing the real study instead of linking to the presentations.

    It explains that: “… the 4th Avenue tunnel option for LRT was identified as performing better as it is adjacent to the DSTT, providing easier transfer opportunities and is located more centrally within the Downtown core (as opposed to being adjacent to the waterfront or I-5).” (Pg. 44 in the Part 7 PDF)

    I think 2nd makes more sense still, but they studied both and DSTT transfers are important. Put me down as sceptical the just like I am with the Eastside studies.

    1. 2nd has a really big sewer line that is in the way. I think 4th also does better due to higher office density.

      The concept they show for a 4th Avenue tunnel transitioning to 2nd would require a bored tunnel.

      1. Someplace under there there is also the BNSF mainline tunnel going between 4th and the waterfront.

      2. The ST study (this is buried in the West Seattle study) seems to suggest a clear winner in a tunnel that is on 2nd through belltown that crosses over the other tunnel (below, I presume) to 4th around Union.
        Regarding Aurora – its our (Seattle Subway) opinion that the right of way in the battery street tunnel is better used by transit than a bunch of rocks from the DBT project.

      3. A tunnel under 4th Ave would avoid the rail tunnel completely, but it would have to cross over the DSTT at the south end, then need to cross it again (under?) around Westlake Station. It would be great to use the opportunity to create an underground passage between the KSS Sounder platform, a 4th Ave line station and IDS. It would be nice to have a decent underground transfer between lines at Westlake Station too.

      4. It could also address the DSTT’s two biggest weaknesses: no Madison/library entrance, and no 4th & Pike entrance (for transferring to eastbound buses).

      5. A rough guess from the map in the study is the alignment is elevated on 6th through SODO, tunneled under 5th in the ID, under 4th north of Yesler, and transitioning to 2nd north of Union.

    2. Three things, and I’ll comment on them separately:

      Yeah, I probably should have linked to the page that links to the studies. I didn’t link to that page because it forces the reader to select various, separate links. I find that annoying, so I figured readers would too. But that is how the full report is presented, so I should just link to it.

      1. I guess I’ll respond to your points in separate posts as well.

        The separate report is super annoying. Somebody with Acrobat Pro or some other software that can merge PDFs, ought to combine the study and host it here or on Seattle Subway’s server or something.

        If worst comes to worst, I’ll do it at school next week and host it on my server.

    3. Second, did they even study a Second Avenue tunnel? Maybe they ruled it out earlier, but in the part seven of the South King County HCT Study they only studied tunnels on fourth, fifth and sixth. I figure it would be cheaper and most effective it it stays just to the west of the other tunnel, then heads northwest, towards Ballard. I didn’t catch where they ruled that out (or why) but such a line would have the same advantage they mention (adjacent to the DSTT, providing easier transfer opportunities). Perhaps it was the issue with the sewer line, although I would think you could squeeze it in between there.

      The study only looked at a couple things:

      1) Light rail from West Seattle.
      2) “BRT” from West Seattle which would then travel along the surface downtown.*

      So, they completely ignored the possibility of having other buses share the tunnel. They didn’t even consider BRT from West Seattle using a tunnel. Given that, I’m not surprised that they came to the conclusions they did. They simply ignored the SoDo busway, because it wasn’t part of their mandate. So I’m not convinced that they have really studied the issue (how best to connect buses from West Seattle (or other areas) to a tunnel connected to trains from Ballard). Even if they did, and the only way to make it work is to cross the other tunnel twice (which is what their rail proposal does) then it really doesn’t change my argument much at all. The southern crossing simply links up to the busway. I’m pretty sure the southern crossing would cross south of the International District, based on what I can see.

      * I don’t know how you could call any bus that runs through downtown “BRT”. That is just ridiculous, but that is all they considered. They did call out the fact that “Potential traffic congestion effects on the surface BRT alternatives were identified, which could reduce transit reliability”. Yeah, really — you think? Then why do you call it BRT! I get really tired of Sound Transit thinking that BRT simply means “cheap and ineffective”.

      1. Your right. It doesn’t look like they studied a 2nd avenue tunnel.

        That seems like a serious oversight on the level of some of the other oversights in the other HCT corridor studies.

        As transit advocates we need to watch these studies and make sure that all the options are properly considered. Including a tunnel for BRT.

      2. The sewer line in question is a huge bored thing, very expensive to move out of the way. I’m pretty sure this is why a tunnel under 2nd wasn’t looked at.

        They did look at 2nd ave elevated. 4th got better ridership probably due to serving the core of the financial district better.

        Crossing,the current LInk ROW isn’t really a big deal as long as you aren’t using cut&cover.

        FWIW I’m not sure there is much of a cost difference between cut&cover and bored tunnels especially in areas with a lot of underground utilities.. Boring has gotten much cheaper and utility relocation is expensive

      3. The argument for 2nd Avenue kind of goes away with the City Center Connector on 1st with exclusive lanes. The tunnel is no longer needed for the west side of downtown, so it makes sense to shift it east to 4th or 5th to balance the transit service. Otherwise you end up with three high-quality corridors bunched together on 1st, 2nd,, and 3rd, and nothing between 4th and 9th.

        Keeping the corridors close may be good for transfering, but 4th Avenue is as close to 3rd as 2nd is, and the CCC will cross the other corridors at two points (Intl Dist and Westlake).

      4. I think the strongest argument for a Second Avenue tunnel is that it might be cheaper. It would basically be a shorter distance to stay to the inside of the other tunnel (rather than crossing it twice). But it turns out, that isn’t the case, given the sewer line.

    4. Lastly, dwell times could improve with the right buses. As I said, I’m not expecting all the buses to go through here. This would be built from the very beginning to accommodate only a subset of lines, just as BRT does. But rather than just painting the buses a different color, these buses would be equipped with more doors and level boarding (like a train). This means more work at the other stops, but that would be relatively cheap.

      1. If the tunnel isn’t exclusively for BRT and LRT then you have to deal with the existing fleet of busses.

        Further more do you have an example of busses that would work?

        If so then only rail bias and capacity remain as LRT advantages.

        This also address Mike’s point, if you only have BRT busses and reduced dwell time then perhaps hybrid operations could really work. Otherwise you are cheeping out on the north end LRT users, while infuriating the West Seattle people who want a train.

      2. I’m not a bus expert, but I seem to remember someone more knowledgeable than me mentioning that buses have that capability. So, I did what every ignorant citizen does — check Wikipedia:

        Sure enough, right there as one of the bullet points is “Platform-level boarding”. Along with “High-capacity vehicles, typically with multiple doors to speed entry and exit.”. So I don’t know the particulars, but it seems like the situation has been addressed before. I would expect that you can load an unload a bus just as quickly as you can load and unload a train car. Given our already huge dwell times at train-only stations, I think any off-board paying, multiple door, platform level bus could load and unload in plenty of time.

        But, like you said, you would need to buy new buses. You would also need to change the bus stops. But all of that is pretty cheap (way cheaper than building a rail line to West Seattle). Which, as you said, then leaves only capacity and rail bias.

        I don’t think capacity is an issue on this line. Capacity is spread out through here. For every rider from West Seattle who wants a fast ride into town there is a rider from Renton. Or Tacoma (or South Park, or Georgetown, etc.). I have no doubt that we would fill the bus tunnel to capacity from the south, it is just that we would fill it with buses from all over, not just one little corner of the city (that doesn’t contain that many people or businesses). They would be special buses, to be sure, but I really don’t see that as a problem.

        If you didn’t know any better, you would assume that the solution would be to simply connect those buses from the south to light rail. But no one is proposing that because Link is just too darn slow through there. This is in big contrast to the north and east side, where it won’t be. Nor is it particularly frequent (although East Link won’t be either). We may get to the point where we ask folks from Tacoma or Renton to transfer to Link, but if they do so, it would cost them a lot of time.

        Which leaves rail bias. This is a big issue, politically. Most people think light rail means grade separation, but BRT means a different colored bus. This is bad, and it hurts the prospects of BRT in areas where it would not only be cost effective, but faster and more frequent for the majority of the riders. But if we can convince people that we can build BRT the way that Wikipedia defines BRT, then maybe we can convince folks from West Seattle that it would be a very good thing.

      3. “Most people think light rail means grade separation, but BRT means a different colored bus.”

        That’s because it often does. RapidRide is a perfect example of that. Light rail was in danger of that too, because every American LR line before Link was watered down to surface-running to keep the cost close to a bus route. ST was courageously pioneering in making Link more grade-separated than that, in spite of the higher cost. And with the First Hill streetcar, ST stuck to a 10-minute frequency and wouldn’t let Seattle lower it to 15 minutes to pay for the Pioneer Square extension. So ST has a pretty good track record, but we should still demand a concrete minimum standard up front just to make sure.

      4. The FHSC will run at 10 minutes only 2 hours a day.

        Sometimes, I have faith in your honestly and earnestness, Mike. Other times, you repeat proven falsehoods with such zeal that I wonder m if you’re no different than the foamer faction.

    5. “they completely ignored the possibility of having other buses share the tunnel. ”

      Probably because they’re having such a bad experience now with buses in the tunnel delaying trains, that they don’t want to do it again.

    6. Interesting, the final report is pretty negative on the value of a Burien – Renton segment. Both the travel pattern maps on page 21 (part 4) and the level 1 bullets on page 33 (part 5) say that the main travel patterns are north-south in both Burien and Renton. “The travel and transit market in the Downtown-West Seattle-Burien corridor is primarily oriented in a north-south direction, which aligns well with the proposed HCT alternatives. The travel and transit market in the Burien-Renton corridor is also generally oriented north-south, which does not directly align with the east-west HCT alternatives. For example, Renton travel is more oriented to Kent and Downtown Seattle.”

      Elsewhere the report discusses elevation challenges going east-west, particularly at I-5 and east of Burien. It contemplates underground stations at TIB and Tukwila Sounder. (Talk about expensive.)

      That makes me think we should cease thinking about a Burien-Renton line and start thinking about a downtown-Renton-Kent line instead. Or Rainier Beach-Renton-Kent as it may be.

  3. Great minds think alike Ross. Details are a bit different but we’ve been talking about this concept as “plan B” for ST3 for the last six months or so. As far as we can tell, its clear winner in the “what if Seattle can only build one thing” battle.

    I also think there is some value in considering mixed operations Even if ST3 does happen (or happens but is smaller than we would like.)

    We plan to talk about this a whole lot more if the legislature fails to get an ST3 funding authority package passed in the next session. Stay tuned.

    1. Thanks Kyle. We think alike on many issues, but I think we disagree a bit what we want in ST3. I want this, not light rail to West Seattle. I also want light rail from Ballard to the UW as well as light rail from Ballard to downtown. For the money, I think this (plus extra spending on other improvements) would be far more effective and popular than light rail on all three corridors.

      1. Ross – we’re closer to agreement on that point than you think. We want ST3 to be as ambitious a plan as possible and reach as many neighborhoods as possible. That said, West Seattle is certainly the 3rd most important corridor when objectively ranked and may not make it into the service plan for that reason. Even with DT to UW via Ballard, A new bus tunnel could have a lot of other upsides too for a marginal additional cost (vs rail only.). All of that starts with an ST3 funding source. Seattle could, failing that, fund ST to build just the West Side Transit Tunnel.

        Generally, regarding West Seattle – It my opinion that you (and DP) tend to downplay the timeline, the value of the incremental step, the political demand, capacity, resiliency issues, and the power of rail bias in your analysis… But I’ll digress – the changes we will be on opposing sides of a real life issue on the subject is nearly zero.

      2. I’m not sure you meant to say “West Seattle is certainly the 3rd most important corridor when objectively ranked”.

        I would say that a line replacing the Metro 8 (snipped at Mount Baker) would be the third most important line, if not the second. Such a line could probably be built for the cost of simply adding one stop on West Seattle. Meanwhile, it would carry lots more people, because it would be much closer to lots more people. Nothing exists in a vacuum, and some of these areas might be covered by other light rail (like Ballard to downtown). But most of these areas are off the radar right now, while we contemplate light rail to Paine Field or Federal Way. But anyway, that is a nice thought exercise, but it doesn’t matter. We have to work within the confines of what has been envisioned, and they haven’t envisioned any light rail for the area covered by Metro 8. So, it won’t be part of ST3. For ST3, I would build the following (for Seattle) listed in priority order:

        1) Light rail from Ballard to the UW.
        2) This (a transit tunnel).
        3) Bus improvements for the region.
        4) Light rail from Ballard to downtown (using the tunnel).
        5) Light rail from West Seattle to downtown.

        Interestingly enough, I would be OK with just the first three. I think it is probably the best value. Once you build fast light rail from Ballard to the UW, there is a lot less need for light rail from Ballard to downtown. Even with a transfer, going via the UW is still pretty fast. The closer you get to the UW, the more it makes sense. This means that the catchment area of a light rail line from Ballard to downtown gets much smaller if you build light rail from Ballard to the UW. Sound Transit is actually a bit worried about that — they don’t want to shovel all those passengers onto the “trunk”. BRT from Ballard to the UW could easily compliment it, though. For folks on 15th or to the west, I think it could do an adequate job. Folks just to the east would take the train to the UW, then downtown.

        But the first four items are solid, even though lots of folks from West Seattle might be disappointed. It is hard to explain to them that BRT could work just as well when we have seen some horrible examples of “BRT” in the city (I’m glad that the streetcar wasn’t called “light rail” — if it was, then folks would never vote for more “light rail”).

        If we built the last one, then the tunnel probably wouldn’t have buses, so some of the improvements to the bus lines would probably go away. Buses traveling northbound on I-5 are pretty much on their own. The busway really doesn’t make sense at this point, unless you go with plan ‘B’ — which is to dig another tunnel just for it to make a turnaround at the international district. That probably isn’t too expensive, but we may not have much money left after building a West Seattle light rail “starter line”. Basically, riders from Tacoma and Renton either have to interact with light rail (which is both slow and infrequent there) or slog through traffic. It would be really weird, because the fastest way from Tacoma to Seattle would be on a bus, but then the bus would have to get into downtown, and whatever advantage the bus had would suddenly disappear. I’m guessing thirty minutes from Tacoma to the edge of downtown, then another twenty just to get from there to the heart of town. It would probably still be faster than Link, though.

      3. Don’t know about popularity; it may be politically difficult to sell two lines to Ballard but none to West Seattle, but it would certainly be effective.

      4. West Seattle is third of the corridors considered. A Denny Way corridor would had to have been promoted ten years ago to be considered this round. The usefulness of the three corridors is clearly:

        1) Ballard to UW (which could double for Ballard-to-downtown trips)
        2) Ballard to downtown
        3) West Seattle to downtown

        That puts us in the position of advocating for two Ballard lines if we can only afford two, but that’s where ridership, acceptance of transit, and willingness to pay transit taxes are: along 45th and between Ballard and downtown. They’re all higher there than elsewhere.

      5. What Mike said about corridors. Regarding ST4, we’ll be starting the long range advocacy effort starting early next year. We’re getting feasibility feedback right now, but I think we have something that would be 100% awesome/of unquestionable value.

        Regarding “two lines to Ballard” — that’s end point fallacy based on how the corridor studies are set up. It would be one line from DT to UW via Ballard. West Seattle before Fremont? Before Wallingford? Before Belltown? Before LQA?

        Anyways — glad to see everyone starting to look at this. We need to keep our feet on the gas to make sure there is SOMETHING big for Seattle on the 2016 ballot.

      6. “It would be one line from DT to UW via Ballard. ”

        Hopefully yes, but ST hasn’t said that yet as far as I’ve heard. And they still decribe how ST will decide what to fund: one, two, or both.

      7. I love the idea of a HCT line replacing the 8 bus though I just wonder if it would be largely redundant at least LQA to Capitol Hill with a new downtown transit tunnel going thru Belltown and LQA combined with the existing Westlake-Capitol Hill Link line? I also wonder how the transfers would work as the 8 crosses a lot of major lines radiating out of downtown, seems there would have to be a lot of stations to hit all the transfer points.

  4. The main issues are the ones Chris Stefan raised above: what is the cost difference between a rail-only tunnel and a rail-bus tunnel, and how much are the other impacts of passenger delays and operational complexity?

    If we start from the hypothesis that it can be “better” than the existing joint operation and less expensive, then how exactly? How much would these help, and how can we guarantee they’ll live up to it? I can see three potential changes at this point: low-floor buses with more wide doors, off-board payment, and/or a lower volume of buses. But with Ballard trains every 10 minutes, four West Seattle bus routes (Fauntleroy, Delridge, 35th, Admiral/Alki), a few Tacoma routes, and some other south end routes (don’t forget the 101 and 150 if they’re still around, and there’s also the 124, 131, 132…) — don’t you reach capacity long before that? I think it could maybe fit the Ballard trains, the West Seattle buses, and some (perhaps not all) Tacoma buses.

    1. Mike — the biggest head scratcher for me in current DSTT operations is actually the follow rules for buses following the rail. Why if following a train any different than following another bus, safety-wise? Changing this would make an enormous difference.

      Also — pulling the trains all the way to the end of the tunnel would be a slight improvement if buses could follow closely.

      And yes — accept no cash fares in the WSTT with ticketing machines on mezzanines and on the platforms.

      If we’re talking about really getting tricky and improving function — run counter flow with center platforms.

      There are currently 17 routes in the DSTT with link. There should be room for Ballard trains, Aurora Trains, West Seattle Trains and Southern trains that turn around in the north part of the tunnel. Right? That is admittedly a very surface analysis — I know the RR routes are more frequent than a lot of current DSTT routes.

    2. @Mike “don’t you reach capacity long before that”?

      I hope so! That is really my point. I don’t expect everyone to be happy. We aren’t going to give everyone in the city a one seat ride to every place they want to go. But if the tunnel is full of buses, then it is a good thing. I would much rather fill the tunnel with bus riders, then have half that many riders on trains. That seems crazy, given the capacity of a train over a bus. But we are only talking about a train serving one little corner of the city (parts of West Seattle) while the buses could come from all over (Tacoma, Renton, other parts of West Seattle, etc.). As I mentioned, Sound Transit expects headways of ten minutes for a West Seattle light rail line (and this is one that has plenty of stops). I know I can beat that with BRT (probably many times over). But that is worse case scenario (assuming that we can’t fit many buses in there). Which brings me to Keith’s point.

      @Kieth — I agree. This is one of the key reasons why we should build this, from the very beginning, to do double duty (BRT and light rail). This could enable us to get reasonable headways. The other issues are really what BRT is all about — as demonstrated not only by the Wikipedia article, but also the current video on the main site ( But that does cost some money, which brings me to Mike’s other point:

      “The main issues are the ones Chris Stefan raised above: what is the cost difference between a rail-only tunnel and a rail-bus tunnel, and how much are the other impacts of passenger delays and operational complexity?”

      I don’t mean to imply that this would be dirt cheap. It would be expensive. But remember, most of the cost of a deep bored tunnel light rail system is the deep bored tunnel itself. We could build another light rail line right through downtown and it wouldn’t be expensive. But add the tunnel and you are talking big bucks (just look at the difference between a streetcar and a light rail tunnel). This is why, generally speaking, BRT is not cost effective. Once you build the grade separation, you might as well add the tracks. But in this case, the grade separation is largely there. There are freeways all over the place south of downtown, and there is a very nice busway. The state has even volunteered (or is at least considering) improving the line (by connecting I-5 HOV lanes to the busway). It just needs “the missing link” (a route through downtown). Building this tunnel won’t be cheap, but it would be worth it. It shouldn’t cost much more to make sure the stations are long enough, or can otherwise handle joint operations in an efficient manner.

      Let’s face it, a lot of our system was hobbled together. I love the transit tunnel. As I said in my intro, it is by far the most cost effective thing we’ve ever built for transit in this city. But it was only vaguely designed to eventually be replaced by rail. There was little talk of subway headways, or mixed mode operations. There is no reason why we can’t build a new tunnel with those things in mind. Pay a little extra and do it right.

  5. I agree that a new downtown transit tunnel is a good project. I also agree that at least one of the Ballard lines should be the highest priority, and that there are some issues with getting to West Seattle.

    However, I don’t find most of the specific arguments here against West Seattle all that convincing. Anyone who spends any time on the C can tell you that it’s far from a truly traffic-separated solution. Sure, in principle the city and state could tell car interests to pound sand and given these buses a truly clear path. But that hasn’t happened yet, doesn’t seem to be on the horizon, and I think it’s unfair to compare a bus system free of these constraints to a rail system that actually addresses them by building new right-of-way.

    I also reject the idea that there’s a fixed sum that voters will approve to allocate as planners see fit. Reducing the quality of the West Seattle line by going to BRT does *not* instantly free up those resources for bus improvements somewhere else. Bus improvements are, unfortunately, unpopular.

    Lastly, the chokepoint nature of this corridor seems tailor-made for a few collection points and a single line into the city. That single line really has to be a high-capacity vehicle; you can’t have people transfer from a full bus to a full bus.

    1. Thanks Martin. I need to write a post that focuses on West Seattle BRT. I thought about adding it to this post, but realized it would simply be too long. A transit tunnel under downtown would be part of it, which is why I wrote this first. I disagree with the idea that serving more people from more areas more frequently from West Seattle is “Reducing the quality of the West Seattle line”. But I understand the confusion, because I haven’t fully clarified the proposal (but hope to soon).

      But I’m also just thinking about writing an article describing what BRT is. A lot of people, including Sound Transit, seem to be confused about the concept. To quote Wikipedia:

      To be considered BRT, buses should operate for a significant part of their journey within a fully dedicated right of way (busway) to avoid traffic congestion. In addition, a true BRT system will have most of the following elements:

      * Alignment in the centre of the road (to avoid typical curb-side delays)
      * Stations with off-board fare collection (to reduce boarding and alighting delay related to paying the driver)
      * Station platforms level with the bus floor (to reduce boarding and alighting delay caused by steps)
      * Bus priority at intersections (to avoid intersection signal delay)

      So, basically, RapidRide is not BRT as defined by Wikipedia. Nor is the South Lake Union Streetcar “light rail”, even though some could call it that (as Mike mentioned above — In both cases, it certainly isn’t what I want us to build in this city. I want BRT as defined by Wikipedia for West Seattle. It wouldn’t be cheap to overcome the traffic obstacles you mention, but it would be cheaper to build than light rail (since at least some of it is already built). By the way, I would welcome more information about traffic obstacles on the C. Where exactly does it bog down (I’ve seen it back up past the entrance on 35th, for example).

      Lastly, I’m not sure which chokepoint corridor you are talking about? You mean SoDo or the West Seattle freeway? If you are talking about SoDo, then that was addressed as an alternative (one I originally supported). Basically, people don’t really want to transfer to a train on the edge of downtown. I am open to exploring that idea more, though, as it is complicated and there are many options, especially as we add another trail line through there.

      If you are calling the West Seattle freeway a chokepoint, I think there is an important distinction to make. It is not the West Seattle part of the West Seattle freeway that is a chokepoint, but I-5. Northbound traffic on I-5* clogs up, backing up all the way to the West Seattle freeway, along with every other entrance. This is why the West Seattle freeway rarely backs up in the opposite direction in the evening (even though the freeway feeds right into a traffic light). For a driver (or a bus) stuck in traffic this distinction is meaningless. But it means that there isn’t enormous demand coming from West Seattle, it is demand along I-5.

      In any event, With sufficient added HOV lanes, the problem (for bus riders) could easily go away. This might not be cheap, but a lot cheaper than adding light rail.

      * By the way, this very issue would have been addressed if we (the state) had spent money on “surface improvements” instead of building a new tunnel for 99. I often think that this was one of the stupidest campaigns ever run. Folks emphasized “surface and transit improvements” without saying that you would also improve I-5. This would have been way more popular if they would have let every driver on I-5 know that there is alternative, and that alternative would be way cheaper and effective in moving cars than building a new tunnel for highway 99 (that now is merely a very short cave).

      1. The Surface/Transit alternative was eventually rebranded as Surface/Transit/I-5, but I digress.

        I do wish you had split this post further: one advocating for a rail-convertible bus tunnel and one ripping West Seattle Link, because the latter partially undercuts the former.

        The basic rhetorical problem you have is that rail advocates have spent a few decades being shown how the same result could theoretically be achieved by something using bus technology. And indeed it could! But the word “theoretically” does a lot of work in that sentence, because BRT already sacrifices a few nice attributes (capacity, comfort, legibility, popularity, robustness to freeway disasters) and inevitably gets watered down further. And here you’re handwaving that the costs must be much, much cheaper without really doing the analytical work.

        More here:

      2. Martin,
        BRT done right is often quite expensive, with costs approaching rail for far less capacity.

        I believe BRT has a place in the transit system. However it shouldn’t be used where the capacity of rail is needed. When the costs begin to approach rail in the same corridor rail is probably the better choice as well.

        Given the politics, I suspect rail to West Seattle will have to be priority #2 in ST3 after Ballard-Downtown. While costs per rider are an issue, I’m not sure the capacity of BRT is sufficient for the demand, particularly through the primary choke point along the bridge and Spokane street. Solving that problem isn’t going to be cheap with either buses or rail.

        The Delridge option A3 is somewhat intriguing as while it would require a transfer to get to the Junction it bypasses most of the bottlenecks at an attractive cost per rider. The total project cost is a bit easier to swallow than the other rail options as well.

  6. Would it be possible, feasible worthwhile to use the tunnel we’re already building…or, trying to build anyway? The DBT, if it’s ever finished, will be a radically fast alternative between the north and south ends of downtown. We know from the toll revenue projections that it won’t be used to capacity by cars and trucks for a variety of reasons like not having downtown exits. We can suspect that WSDOT is looking for money to cover the cost overruns that are likely coming from all the delays and extra work. They may be willing to add on something of value to transit for a bargain price if it patches their hole. Why can’t we build one bus station somewhere alongside that tube? I honestly can’t believe this wasn’t in the design all along. The timing is perfect for buses coming out of the other tunnel. It could have a nice connection to the 1st Ave streetcar for distribution. It would only cost the amount needed to create the station, not a whole new tunnel. I’m sure the engineers can figure it out. Acceleration/reentry lanes could be short if there was a lower speed limit / warning signals in the outside travel lane near the station. I totally agree something should be done to keep buses off the surface. Was this studied and rejected or is there something I’m missing? Seems like we should use what we’re already building and make the most of it.

    1. Possible in the sense that it could be done if you threw enough money at it.

      I suspect purpose building a transit tunnel would be cheaper and better suited to the task.

  7. So why not keep the existing tunnel as bus-rail as it was designed and build the new tunnel as rail only? Seems kind of crazy to me to convert a bus-rail tunnel to rail only then build a new bus-rail tunnel.

    By the way, why isn’t there a main entrance into Westlake Station from Westlake Park which would also help connect to the buses going up Pike? Westlake Park/Square is a dump anyway and this would get more foot traffic through the plaza and activate it at night.

Comments are closed.