Transit and Scale Variance Part 1: Bus Networks

I intend to begin a series of posts, about the concept of scale-variance in public transit. What I mean by scale-variance is that things work dramatically differently depending on the size of the network. This can include any of the following issues, roughly in increasing order of complexity:

  • Economies and diseconomies of scale: cars display diseconomies of scale (it’s easier to build freeway lanes numbers 1-6 than lanes 14-20), transit displays the opposite (there’s a reason why the world’s largest city also has the highest per capita rail ridership).
  • Barriers to entry: a modern first-world transit network, or an intercity rail network, requires vast capital investment, beyond the ability of any startup, which is why startup culture denigrates fixed-route transit and tries to find alternatives that work better at small scale, and then fails to scale them up.
  • Network design: the optimal subway network of 500 km looks different from the optimal network of 70 km, and its first 70 km may still look different from the optimal 70 km network. Bus networks look different from both, due to differences in vehicle size, flexibility, and right-of-way quality (surface running vs. grade separations).
  • Rider demographics: the social class of riders who will ride half-hourly buses is different from the class who will ride the subway, and the network design should account for that, e.g. by designing systems that the middle class will never ride to destinations that are useful to the working class. But then marginal rider demographics are profoundly different – sometimes the marginal rider on a low-usage bus network is a peak suburban commuter, leading to design changes that may not work in higher-volume settings.

For a contrasting example of scale-invariance, consider timed transfers: they underlie the Swiss intercity rail network, but also some small-town American bus systems and mid-size night bus networks such as Vancouver’s. I wrote about it in the context of TransitMatters’ NightBus proposal for Boston, giving a lot of parallels between buses and trains that work at many scales.

However, night buses themselves are an edge case, and usually, bus network design is different at different scales. In this post I’d like to go over some cases of changes that work at one scale but not at other scales.


The trigger for this post was a brief Twitter flamewar I had earlier today, about Brampton. TVO just published an article praising Brampton Transit for its rapid growth in bus ridership, up from 9 million in 2005 to 27 million in 2017. Brampton is a rapidly growing suburb of 600,000 people, but transit ridership has grown much faster than population. The bone of contention is that current ridership is only 45 annual bus trips per capita, which is weak by the standard of even partly transit-oriented places (Los Angeles County’s total annual bus and rail ridership is about 40 per capita), but is pretty good by the standard of auto-oriented sprawl. The question is, is Brampton’s transit success replicable elsewhere? I’d argue that no.

First, Brampton’s transit ridership growth is less impressive than it looks, given changing demographics. Fast growth masks the extent of white flight in the city: it had 433,000 visible minorities in 2016, up from 246,000 in 2006 and 130,000 in 2001, and only 153,000 whites, down from 185,000 in 2006 and 194,000 in 2001. The TVO article points to racial divisions about transit, in which the white establishment killed a light rail line over concerns about traffic, whereas the black and South Asian population (collectively a majority of the city’s population) was supportive. Ridership per nonwhite resident is still up, but not by such an impressive amount. Brampton’s population density, 2,200 per square kilometer, is high for a North American suburb, and a change in demographics could trigger ridership growth – this density really is okay for both transit and driving, whereas very high density (e.g. New York) favors transit and very low density (e.g. most of the US Sunbelt) favors driving regardless of demographics.

But even with demographic changes, Brampton has clearly gotten something right. I compare ridership today to ridership in 2005 because that’s when various bus improvements began. These improvements include the following:

  • A bus grid, with straighter routes.
  • More service to the airport.
  • Free transfers within a two-hour window.
  • New limited-stop buses on the major trunks, branded as Züm.

The bus grid is not especially frequent. The Züm routes have variants and short-turns, with routes every 10-12 minutes on some trunks and every 20-25 on branches and the lower-use trunk lines.

This isn’t the stuff high ridership is made of. Most importantly, this is unlikely to be the stuff higher ridership in Brampton could be made of. The Toronto region is electrifying commuter rail in preparation for frequent all-day service, called the RER. One of Brampton’s stations, Bramalea, will get 15-minute rail frequency all day; but Brampton Station itself, at the intersection of the two main Züm routes, will still only have hourly midday service. With fast service to Toronto, the most important thing to do with Brampton buses is to feed the RER (and get the RER to serve Downtown Brampton frequently), with timed transfers in Downtown Brampton if possible.

The express buses are specifically more useful for low-transit cities than for high-transit ones. In low-transit cities, the travel market for transit consists of poor people, and commuters who want to avoid peak traffic. Poor people benefit from long transfer windows and from a grid network, whereas commuters only ride at rush hour and only to the most congested areas; in Brampton, where city center doesn’t amount to much, this underlies the express bus to the airport, and the trains that run to Downtown Toronto today.

The marginal rider in Brampton today is either a working-class immigrant who can’t afford Toronto, or a car-owning commuter who drives everywhere except the most congested destinations, such as Downtown Toronto at rush hour, or the airport. Brampton has catered to these riders, underlying fast bus ridership growth. But they’re not enough to lead to transit revival.

Bus grids

The value of a bus grid in which passengers are expected to transfer to get to many destinations rises with the frequency of the trunk lines. In Vancouver and Toronto, the main grid buses come every 5-10 minutes off-peak, depending on the route, and connect to subway lines. Waiting time is limited compared with the 15-minute grids common in American Sunbelt cities with bus network redesigns, such as San Jose and Houston.

The difference between waiting 15 minutes and waiting 7.5 minutes may seem like a matter of degree and not of kind, but compared with bus trip length, it is substantial. Buses are generally a mode of transportation for short trips, because they are slow, and people don’t like spending all day traveling. The average unlinked bus trip in Houston is 24 minutes according to the National Transit Database. In San Jose, it’s 27 minutes. Breaking one-seat rides into two-seat rides, with the bus schedules inconsistent (“show up and go”) and the connections not timed, means that on many trips the maximum wait time can be larger than the in-vehicle travel time.

The other issue coming from scale is that frequent bus network don’t work in sufficiently large cities. Los Angeles can run frequent bus lines on key corridors like Vermont and Western and even them them dedicated lanes, but ultimately it’s 37 km from San Pedro to Wilshire and an hourly bus on the freeway will beat any frequency of bus on an arterial. There’s a maximum size limit when the bus runs at 20 km/h in low-density cities (maybe 30 in some exceptional cases, like low-density areas of Vancouver with not much traffic and signal priority), and cars travel at 80 km/h on the freeway.

This has strong implications to the optimal design of bus networks even in gridded cities. In environments without grids, like Boston, I think people understand that buses work mostly as rail feeders (it helps that Boston’s public transit is exceptionally rail-centric by the standards of other US cities with similar transit use levels, like Chicago or San Francisco). But in sufficiently large cities, buses have to work the same way even with grids, because travel times on surface arterials are just too long. The sort of grid plan that’s used for buses in Chicago and Toronto is less useful in the much larger Los Angeles Basin.


  1. andrewla

    First, Brampton’s transit ridership growth is less impressive than it looks, given changing demographics. Fast growth masks the extent of white flight in the city

    Is the argument that other cities can’t replicate this because they already had their white flight?

    • Alon Levy

      The argument is that Brampton’s transit growth is in part due to replacement of middle-class whites with working-class nonwhite immigrants. This can’t happen on a national level, contra far-right replacement theory; white Canadians are still having babies, at almost-replacement rate.

      • Jonathan

        While the demographics of Brampton are certainly changing as it grows, it’s not really accurate to say that middle-class whites are being replaced with working-class nonwhite immigrants. They are being replaced with middle-class nonwhite immigrants. For example, median household income rose in Brampton has been climbing through this change, to $87,290 in 2015 from $77,787 in 2010.

          • Jonathan

            For sure, it isn’t as affluent a suburb as Markham or Oakville. But the point is that as it has gotten less white, median incomes have gone up not down. So it’s not simply a story of the city becoming poorer.

          • adirondacker12800

            Surely you are looking at median. ,,,,Bill Gates and Warren Buffet walk into a bar. The average income of people in the bar shoots through the roof but the median stays almost the same. Per capita can be interesting but so is household and family income. Distribution of people living in poverty too.

          • PlannerMike

            Per capita incomes are usually below the average in most large urban areas. This is a larger number of varying family types in large urban areas. It does not mean, however, that all the people taking the bus are poor.

    • PlannerMike

      The race of the population has nothing to do with ridership, and should not even be factored.
      Transit is used by residents of all incomes and races in most Canadian cities.

      • Alon Levy

        Okay, but the article I’m basing this on explicitly says that the nonwhite residents supported light rail whereas the white ones opposed it.

        • adirondacker12800

          Very likely it was there were other demographic differences too. Age. language spoken at home. Cable versus satellite…

  2. Untangled

    Brampton’s density is quite high but it’s worth noting that this density is the tower in the park type of density. The setbacks for these towers are huge, the roads are wide and unwalkable, all the activities like jobs and shopping malls are dispersed rather than centrally located in downtown Brampton. That is not a good setup for greater public transport usage, for travel within the city-suburb or elsewhere except the places mentioned, and everything else is generally laid out more like a typical suburb. RER, LRT and feeders might help but the ship has sailed in Brampton and Bramalea. Unless they start all over.

    • Alon Levy

      Light rail might still happen – they built the line in Mississauga, and are waiting for Brampton to approve its own segment. Eventually the white NIMBYs will no longer politically dominate a city where they’re 23% of the population.

    • Eric

      Looking at Google 3D maps, there are only a couple blocks of “towers in a park” development. The rest appears to be single family houses (on relatively small lots) and industrial areas.

      • PlannerMike

        While the layout of the subdivisions is still suburban. The density of the single family housing in Brampton and most Toronto suburbs is actually very dense. In most cases, the density in these new subdivisions is similar to that of some of the inner city neighbourhoods in Toronto. In fact, many of the newer homes in Brampton have less backyard space than homes in the inner city of Toronto.

        The density is there. It is just that the rest of the subdivisions are still built very suburban, with strip plazas, etc.

    • PlannerMike

      The built environment in Brampton is not as bad as you make it out to be. It is also no different than the older suburbs of Toronto which support high levels of transit usage and pedestrians (because of the high transit usage).
      Could Brampton be designed better? Of course. But it is far from the worse place for a pedestrian or transit user.

      Most Brampton neighbourhoods are centred on a central town centre area, be it Bramalea City Centre, Heart Lake Town Centre, Shoppers World, Downtown Brampton, or Trinity Common.

      Brampton has major activities centred around the Bramalea City Centre Mall. This area supports pretty strong transit usage, and functions as a downtown for the area. We have to stop looking at suburban developments and assuming that it is not good, because it was built post war and in a suburban style. Bramalea City Centre is basically a downtown. Just the shopping happens to be in a mall. But the areas functions well as a hub.

      • Untangled

        Downtown Brampton itself doesn’t look too bad but outside of that, the built environment isn’t very nice for a pedestrian or transit user, it might be slightly better sprawlsville because of its density but it’s still very much a North American suburb.

        The hubs are too dispersed rather than centrally located, you listed those many hubs. For a place with just over half a million people, that’s a tad too much and none of them bar one is located near the train stations. Ideally, there would be just 2, both would be around Brampton and Bramalea station and would be much stronger any of the numerous ones that exist today. Bramalea City Centre Mall is surrounded by tons of parking on all sides. Although I shouldn’t single out Brampton, Mississauga is like that but even worse (I’m especially looking at places like Meadowvale, Airport Corporate Centre, etc – ideally all these places will be located near Square One).

        The reason why I say this is because I recently found out that Sydney and GTA has a similar public transit mode share (27 vs 24%) but Sydney is much less dense than GTA, especially in weighted density. Sydney is less dense than even Vancouver but has a transit higher mode share.

        So what accounts for this? Sydney seemed to do one thing quite well that seemed to go a long way to make up for the lack of density, centrally locating as much as possible creating bigger, fairly urban commercial hubs all over the metropolitan area and some are quite congested. They are often near train stations with offices, jobs, shops including shopping malls, etc. It’s like Downtown Brampton but bigger. This seems to help lift transit despite the lack of density. (Although I will say that a decent regional rail system is probably needed.) You won’t find shopping malls surrounded by tons of parking in Sydney, all the mall parking is in multistory structures and malls are typically built right up to the sidewalk in Sydney, even deep in the suburbs. And remember Australia had similar post-war suburban forces as North America.

        The funny thing is that even though both cities have similar transit mode share, they had different ways of getting there, to simplify it, one has good density but bad suburban hubs (Toronto) and another has good hubs but bad density (Sydney). Public transport isn’t all about density if it was GTA would smash Sydney in mode share. Of course, Sydney’s suburban hubs can still be drastically improved. It would be really interesting to see how GTA develops with suburban transit improvements.

        • Eric

          I think the US built unwalkable neighborhoods for the sole purpose of keeping out “crime” (i.e. black teenagers who didn’t have access to cars). I suppose this is less of an issue in Australia (a more homogeneous population)?

          • adirondacker12800

            The kind of people who are gonna break into your house and steal your 55 inch TV are the kind of people who know how, or know someone, who knows how to steal cars.

          • Michael James

            Eric 2018/01/11 – 15:38

            I think the US built unwalkable neighborhoods for the sole purpose of keeping out “crime” (i.e. black teenagers who didn’t have access to cars). I suppose this is less of an issue in Australia (a more homogeneous population)?

            No. Guns. And cops don’t turn up and shoot the suburban (white) woman who just made the 911 call.

            Australia has one quarter of its population born elsewhere–the highest in the world–and 10% have at least one parent born in Asia. We’re en route to becoming a Eurasian nation even if Kiwis are still a dominant “immigrant” group (they don’t have to ask permission to live in Oz; 10% of NZ population lives in Oz, hence the Russell Crows etc) and Melbourne is said to be the largest Greek city outside of Greece.

          • Michael James

            Yes, Alon, highest in the world.
            Well the only one on that absurd list that is nominally higher is Switzerland with 28.9% versus Australia’s 27.7%. But less than one third of “resident foreigners” are citizens (another third are Germans +Italians + French who possibly work in Switzerland but live across the border (common in Geneva and Basel). The next “real” cases are NZ (25.2%) then Canada (21.9%). The US is at 14.3%, Germany at 14.9%, UK at 13.2%.
            All of the ones above us are artifactual or meaningless (Lichtenstein & Luxembourg, Vatican etc.; Andorra whose sovereignty is shared by Spain & France; many of these shouldn’t be on the list) whose population comes from their surrounding states or who officially have citizenship different to these mini-states. Singapore is clearly in this same category. The first bunch on the list are Arab states with zillions of guest-workers (who will never obtain citizenship). The UAE has 84% resident foreigners but how many are destined or planning or will be allowed to become citizens? Or those tiny British island tax-havens who have citizenship elsewhere (and probably residency too given their amenability to such arrangements). Hong Kong is high on the list despite it being 92% ethnically Han Chinese!

            I think again this shows up your rather blind econocratic approach to things. That approach would lead you to proclaim Vatican city (100%) as the highest in the world and the most multi-culti! See the problem?

            Demographers will tell you that Australia is the most multi-culti country in the world. The majority are citizens, with almost all of them destined to become citizens. And from all over the world.

          • Alon Levy

            Among the large countries of the developed world, the most racially diverse one is the US. Don’t forget black people and second- and third-generation Hispanics and Asians in your calculations; Australia didn’t historically have anything like that, for reasons like the White Australia policy. On other markers of ethnicity, like language, Switzerland and Belgium are very diverse, as are Singapore and Canada, all to much greater extent than Australia.

            Australia isn’t especially multicultural. It likes to tell itself it is, but it isn’t. Same thing with the “we’re a Eurasian nation” bit – no, you’re not. Ask any Singaporean whether they view Australians as even remotely Asian; they barely register second-generation Asian-Americans and Asian-Canadians as Asian, and I don’t think the mentality toward Asian-Australians is any different. In Singapore, you speak English with something that sounds like British or American accent = you’re an expat.

          • Michael James

            Alon, you keep changing the subject or are unable to stay on topic (which was immigrants). I don’t know why I would care what “any Singaporean’s” view on anything would be. Especially when about one third of Singaporeans, especially the young, would migrate to Australia tomorrow if they had the opportunity (and “other things being equal”–which of course, due to family ties–they are not). But the Singaporeans most likely to comment on Australia will be those in positions of influence and power who happen to have been educated in Australia (perhaps it is a cheapo alternative to their great leader’s Cambridge but much more practical for most Singaporeans; Australia’s provision of education to a lot of Asia’s middle-classes is a hidden soft-power we have, though often wasted or neglected, or even abused.).
            I didn’t say Australia is a Eurasian nation but that that is its fate. One I embrace (total disclosure, I have a bit of Cantonese in my pedigree), and despite the rhetoric you may hear in the media about some anti-Asian sentiment, this won’t be a problem. Though it is true, one doesn’t proclaim it as policy but it really is our demographic fate and a good one*. Indeed one of the more popular politicians is Penny Wong, opposition leader in the Senate, who is part Malaysian, part-Chinese, first openly-gay Cabinet minister (in previous government), and someone the rest of the world will be seeing more of after the next election when she will become Labor’s minister of Foreign Affairs. Remember too that a previous recent PM (Kevin Rudd) was fluent in Mandarin (the second most common language spoken in Australian households).
            My viewpoint is that it is the dull British culture that is the problem with our nation. Though it is marginally better than the Calvinist + Quaker (English, Dutch, German etc) religious extremist heritage of the US. Our history is much closer to California with which we shared a gold rush and the influx of Chinese that that provoked in the mid-19th century. Also I should make clear that I actually agree(d) with Singapore’s Lee Kwan Yew’s notorious comment about Australia: “the white trash of Asia”. He subsequently relented but the only reason we won’t remain that is because we will have become Eurasian! (So really he was correct.)
            *The recent byelection in the inner-Sydney federal seat of Bennelong is a case in point. The irony too is that the byelection was brought about by the discovery of the incumbent’s dual-citizenship (of the UK, by inheritance, not allowed for federal parliamentarians–they must legally renounce other nationalities by the time of nomination). Census data is rather complicated but here is my selection of “both parents born overseas” and only showing those with >1,000 (Vietnamese, Indonesians, Malaysians etc are present but just under this threshold). (source: Australian Bureau of Statistics):

            Australian 1,239
            Chinese 29,262
            English 7,296
            Korean 6,831
            Indian 5,133
            Italian 4,317
            Filipino 2,072
            Lebanese 1,884
            Irish 1,760
            Scottish 1,636
            Greek 1,386
            German 1,077

            Total responses: 87,863

            Bennelong is one of the most prosperous electorates in Australia (if not quite “North Shore” or “Eastern Suburbs” of Sydney), and these Chinese and others are rather conservative middle-class successful business types etc. (quite a few from Singapore, no doubt). The electorate has become more “ethnic” over the last two decades and in 2008 it actually kicked out the then-PM John Howard (who poetically lost both his party’s re-election federally and his own electorate) who had a persistent (fully deserved) “dog whistling” racist reputation, plus along with Kevin Rudd’s popularity and Mandarin-speaking local appearances during the election. Another curiosity of the byelection was Labor’s candidate, Kristina Keneally an American-born former Premier of NSW, and now destined for federal parliament via the Senate–she brought about a 7% swing but it wasn’t quite enough to capture the electorate for Labor (like I said, it is naturally fairly conservative though heading to Labor). So sometimes even our poor white trash speaks with an American accent! (born in Las Vegas no less, grew up in Toledo, Ohio). Oh, another delicious factlet to mention is that during her period in office, there was a total dominance of the “chain of command” by the matriarchy: QEII, Governor General (Quentin Bryce), PM (Julia Gillard), Premier of NSW (KK), Governor of NSW (Marie Bashir, with Lebanese-born parents) and Mayor of Sydney (Clover Moore). You’ll notice the predominance of immigrant background in this lot, not least that the top two elected politicians were not Australian-born (Gillard was born in Wales).

  3. ckrueger99

    Gosh, why would Bramalea get 15 min service instead of Brampton? With Brampton, a small amount of infill TOD and you have the beginnings of a downtown. Can’t say that for Bramalea.

    • Fbfree

      Beyond Bramalea, there is significant freight train interference on the tracks, this being the CN mainline between Toronto (MacMillan yard) and Chicago. Eventually, additional transit capacity may be provided on the corridor, but given the expense, it’s supplanted by other priorities such as electrification.

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