The sparseness of the rapid network

San Francisco has complicated geography. While the hills are nice to look at and offer some great views and parks, they’ve also forced Muni to do some suboptimal network design. Hills will break up the street grid and be very hard to pass over. We can see this quite clearly with Mt. Sutro and the Twin Peaks, which cut off the Castro/Noe Valley street grid from the Sunset one. This makes it difficult to design an east-west line that fills in the gap between the N and the L. The 7 tries to avoid this by coming in from Lincoln Way, and the 48 up from West Portal (though only during peak hours), but large areas are still left uncovered and the innermost bits of the Sunset aren’t well served by this sort of design. Hills also break up Noe Valley and Glen Park, making continuous north-south lines difficult.

In addition, I think that the hills and narrower streets that some of the highest-ridership lines traverse have prevented them from getting rapid buses added to them. I would expect the criteria for adding a rapid bus to be something like the following:

  • High ridership
  • Lots of transfers to other high-ridership lines
  • Long route
  • Dense stop spacing on the local

If we look at just the rapid network, it seems to be very commute-focused, with few crosscutting lines except for the 28-19th Avenue. Entire areas of the city also seem to be lacking in rapid service.

I excluded the 7R-Haight/Noriega Rapid here because it skips so few stops that it might as well be a local.

Just about every line here serves to get people downtown! By contrast, the area just west of downtown LA seems to have no problem implementing a rapid grid in addition to its locals.


It’s missing a few pieces—perhaps rapid lines on Beverly and La Brea—but the grid structure is clear here. Can we look at something similar for SF? First, we need to decide which lines are due for rapid upgrades. The Van Ness section of the 47 and 49 will essentially be rapid once Van Ness BRT is complete, so that’s a start. Having a 49R to complete the rest of that journey would be nice as well, and Muni does seem to be planning something along these lines. I have some ideas for other upgrades, ranked roughly from what I think are the best options to the worst:

  • 29-Sunset (19k riders/weekday, crosstown line, connections to most rapids and Balboa Park Station)
  • 44-O’Shaughnessy (17k riders/weekday, crosstown line, connections to most rapids and Glen Park Station)
  • 1-California (26k riders/weekday, 29k with express routes, adds service north of Geary)
  • Either the 22-Fillmore (16k riders/weekday) or 24-Divisadero (10k riders/weekday, but longer route and denser spacing)
  • 45-Union/Stockton (10k riders/weekday, goes through an area with little rapid coverage, though the route is shorter)


So what’s stopping us from upgrading these lines? One of the interesting things about rapid buses is that if they are deployed along frequent local bus lines, they won’t really save much time or go much faster if they can’t pass the local buses. This means that trolleybus lines that are potentially too steep for a full motorcoach are immediately off the table! The 1, 22, 24, and 45 won’t be able to have rapid service for this reason. This is a real bummer, since the 22 or 24 would have filled a nice gap in the middle and added a crosstown rapid line. Additionally, the stop spacing on the 24 is so dense in some areas that it stops are not even 600 feet apart—sometimes even under 300 feet! It would have been nice to have a fast ride at times other than the middle of the night, but it’s not looking too good right now.

Can we at least add rapid service to the 29 and 44? Passing on normal two-lane streets is harder, but still possible. From the Presidio terminus to about Holloway & 19th Ave, the 29 is mostly on large streets where passing is easy. The same is true while it’s on Ocean. Otherwise, the streets are narrow and might not allow passing, and passing on Mansell would probably be dangerous for bikers. The 44 spends a lot of time on large roads as well, and Silver is a better street to pass on than most with only one lane in each direction.

What does the rapid network look like with these additions?



Still not perfect, but it’s getting there! We have some semblance of a grid in the southern and western areas of the city now. Twin Peaks has a faster way to go crosstown. The northern areas are still underserved, but I’m not sure there’s a good solution to that short of a Union St subway. Perhaps something could be done using Broadway since it is flat, wide, and the area seems like it could use the service, but it wouldn’t line up with any existing line and would probably be the result of some rejiggering of the lines that are already in the area.

A downtown subway grid

Recently, the SFCTA, SFMTA and various other transportation organizations released a website called Subway Vision. It aims to collect ideas from everybody about where to install new subways in SF. The Subway Master Plan is supposed to ensure that we are always building a subway, and we currently have the Central Subway under construction, along with planning for the M subway and construction hopefully in the not-too-distant future. Future expansion plans are also being considered right now, as the Rail Capacity Strategy report released back in February gives an outline of what Muni thinks its next steps will be.

People spend a lot of time talking about Geary whenever new subways are discussed. And that’s great! Having high-capacity transit on Geary is extremely important given that its bus lines ferry the same ridership as Caltrain. BRT will definitely help, and we’ll see how this develops in the future. However, I think the need for new subways downtown is often overshadowed by this discussion. Our current rail network has one subway that goes from downtown outwards, through which a large percentage of its 150,000 daily riders go. This is a huge bottleneck! Problems that occur in the subway here are liable to delay many people and cause lots of gaps and bunches. If there is one thing we can learn from New York here, it is that these problems are way more tolerable when there is some redundancy.

Having extra subways parallel to the Market Street Subway downtown is hardly a new idea. SPUR advanced the idea in this report and has implied it in various materials concerning a second Transbay Tube. By pulling together some ideas from these and the Rail Capacity Strategy, we can come up with a nice grid-like structure for subways in downtown SF.

First, if we look at the Rail Capacity Strategy, we find that Muni eventually wants to put LRT on Geary. LRT will improve capacity even more than BRT, but the most interesting part about the plan is the fact that it might be a hybrid subway/surface line. Muni gives cost estimates for all of the involved projects in the report, and the lowest estimate for Geary LRT appears to be the cost of installing surface rail along its entire length at a cost of about $1.4 billion. By using the estimated cost of installing other subways and doing some math, we can figure out that the $3 billion upper bound makes sense if Muni installs a mile of subway and 5 miles of surface rail. One mile of subway takes us from Market to about Van Ness along Geary, which is a reasonable option.

But why should we stop at Market? Merging into the Market Street Subway is probably not feasible, since it’s not possible to fit a flyover junction when there is already another subway below. Even if it were possible, it would probably be ill-advised, as we’d get one extra stop at the expense of subjecting the new subway to all of the same problems we get by combining the other lines. But there are other options—the report also has lots of figures for job and population density in various sections of the city, and we can use those to extend the route. 2nd St in particular has a very high density of both, and a subway in the Geary area could connect through Mongtomery Station and continue into SoMa along 2nd St. This line could be anchored at AT&T Park, which is surrounded by a commercial district, and which often relies on the easily-overwhelmed Muni Metro Extension to get people in and out on game days. 2nd St is also slated for an upgrade to LRT in the distant future, according to the Rail Capacity Strategy.

It might seem like overservice, and while the redundancy with the Central Subway is nice, that’s not really what we’re after. The grid really comes together when we install a subway along Folsom. Folsom is considered one of twelve high-priority corridors for expansion by Muni. By pulling a line out of the Market Street Subway between Church and Van Ness and instead sending it up Folsom, we solve a number of problems:

  • Fewer lines are merging at Van Ness, which means we can mitigate a bottleneck there
  • The already-existing flyover junction would make construction of the other one less disruptive, since we wouldn’t have to reconfigure the current subway
  • In the event of backups in the Market Street Subway, all KLM trains could reroute into the Folsom Street Subway instead, mitigating delays (J and N trains could stop at Church & Duboce for transfer) and still allowing decent access to Montgomery and Powell areas via the 2nd/Geary and Central Subways

In this proposal I choose the L train to be pulled out in standard service because we can’t pull out the J or N, as the new trains will leave the MSS before the J or N merge in; the M is going to improve capacity in the MSS after its subway expansion and use of longer trains, which is important; and the K can only run short trains at the time being, and may still be used to serve the Muni Metro Extension.

The end result is a grid-like structure centered on 2nd, 4th, Market and Folsom Sts, with additional transfer points along the Embarcadero and on King. Here’s what it looks like:

Above-ground stops are circled with gray, and Van Ness BRT is shown as the green dashed line.

There’s also room for further expansion: Leavenworth, Civic Center and 7th St stations all line up quite nicely, for instance (and would be easily connected by the bus I laid out in earlier articles). If the Caltrain railyard is rebuilt underground and the 280 spur is at least partially torn down, this could open up enough land that extending the Muni Metro Extension out to 7th St and building more rail along 7th St makes sense, as well. Some ideas for extending high-capacity transit along Van Ness send it down 11th St and Potrero Ave, in which case they would also fit nicely into this grid; extensions down Mission could also use the transfer to the new station at Duboce Ave. Sadly, I think the Chinatown T stop is too far north to have a really easy transfer, but a line down Sacramento St might be useful and connect Van Ness BRT with Embarcadero and Main St Stations. The T would be within reasonable walking distance of such a line.

This expansion provides a lot of extra options for people to move around on corridors that Muni considers important, and getting them into a shape where they work well together. Having redundant infrastructure makes the system more resilient and also makes it easier to justify arbitrary planned service changes, which people will need to deal with if we ever eventually want 24-hour rail service.

But don’t just take my word for what subways are worthwhile to build. With Subway Vision, Muni is giving all of us an opportunity to influence the evolution of the city. We should use this opportunity to tell them what we think!

Completing the grid: The Tenderloin gap, part I

If you look at a transit map of San Francisco, you might find some surprising holes in the coverage. Perhaps we can learn something about network planning by trying to fill them in.

One of the more confusing examples of this is the lack of north-south lines running through the Tenderloin, Nob Hill, and Russian Hill. The Tenderloin is one of the densest areas in the city and has a lot of below-market-rate housing, so adding service would increase mobility for a lot of people. Nob Hill and Russian Hill are also very dense and poorly connected by transit, which means we have a big opportunity here.

Fisherman’s Wharf employers have trouble filling positions because the area is out of the way, and having more service there could bring in more employees and tourists. Because it is such a big destination and it just north of Russian Hill, it can serve as an anchor for one end of the line. Another important point on this line would be a connection to Muni Metro and BART.

Lastly, if we want a frequent grid that functions well, we have to make sure the grid lines are not spaced too far apart, or our reliably-covered areas will have huge gaps.

Let’s look at the current map of north-south lines to see what we’re up against.


You might look at this and say, “Coverage seems fine!” That’s true, but for such an important area, there is startlingly little frequent transit, and the lines aren’t very simple. If we evaluate each of these lines, the picture comes out much bleaker.

First, let’s look at the 19-Polk. North of the Tenderloin, this bus is basically a less reliable Van Ness bus. It runs less frequently, there is no owl coverage, and any speed problems plaguing Van Ness buses will be put to rest by Van Ness BRT in a few years anyway. I’d wager that any time the 19 saves by going faster is cancelled out by the extra wait. The portion in the Tenderloin has one-way splits, and they cross over each other a few times, making the route harder to remember. Perhaps it is useful for connecting some areas to Civic Center Station, but it seems to me more like the old 26-Valencia, which was an infrequent bus next to a bunch of really important and frequent lines running on Mission. The 26-Valencia was discontinued in 2009 for this reason.

Let’s update the map.


Next, let’s talk about the 27-Bryant. This bus has a number of problems. First and foremost, it does serve the Tenderloin, but its route is plagued with so many leapfrogging one-way splits that it’s impossible to remember where the stops are! It seems like planners were trying to follow an imaginary extension of 5th St northwest on the other side of Market. Dragging this diagonal line across a normal grid is a recipe for disaster and the incredibly confusing route proves this.

This line also has a poorly-anchored terminus at Van Ness between Washington and Jackson. I don’t know of anything there that will attract riders other that the connection to the 47 and 49 lines and possibly the Academy of Art. It seems like the decision to terminate the line there was an attempt to keep Tenderloin bus riders out of Russian Hill, especially when you compare the route of the 27 to its neighboring cable car routes (which we’ll get to in a minute).

In addition to problems with the alignment, the bus is not that frequent. I don’t think this is a suitable north-south line in the frequent grid. One more time:


The cable cars are interesting, because they are actually quite frequent. They are anchored at both ends by Union Square in the south and Fisherman’s Wharf/Aquatic Park and North Beach in the north. However, they are specifically routed around the Tenderloin, likely to avoid serving its residents. This shows they are aimed at wealthy Russian Hill/Nob Hill residents and tourists, and aren’t a useful part of the grid, either.

It is important to note that the Tenderloin used to have more cable car routes, and the cable cars used to be a more equitable mode of transit. This fell apart in the mid-1950s when the city government was trying to dismantle the Tenderloin. One of their weapons was removal of cable cars that went through the neighborhood, which city officials claimed were “dragging down” the city. The city said the cable cars were slowing down automobile traffic in Union Square, which it was desperately trying to expand into the Tenderloin. They also promised to replace the affected lines with buses as part of a “modernization” effort.[1]

It’s clear that this was a move to contain the Tenderloin and its people rather than improve the transit network. It wrecked transit access in the Tenderloin and we can still see the effects today. Here’s what we’re left with.


This is the north-south component of our frequent grid in this area. It looks a little bare, doesn’t it? This, too, has problems for anyone living in the center. The one-way splits on the 8-Bayshore and 30-Stockton are extremely wide (4 blocks apart!) and so the area which you can really call “covered” by those buses is greatly diminished. The 8-Bayshore is split all the way up to Columbus, making it especially useless in the middle area.

The distance between the Van Ness buses and the Stockton buses is also very far:


Keep in mind that all of the northbound Stockton buses use Kearny when they are south of Sutter. That means your nearest frequent bus might be half a mile away, and south of O’Farrell, it might be even worse! In the average case, it’s still 8/10 of a mile between routes. Noted transit planner Jarrett Walker often talks about frequent grids in network design and says that parallel lines should be generally 1/2 mile apart and at most 3/4 mile apart, so a gap this large means we are underserving the middle area.

I think we’ve laid out the case for having another frequent north-south line here. Next time I’ll discuss what we should think about when we design it.

  1. The Tenderloin: Sex, Crime, and Resistance in the Heart of San Francisco by Randy Shaw, pp. 96-98