Transit-Oriented Suburbs

I did a Patreon poll last month with three options, all about development and transit: CBDs and job concentration in middle-income cities (e.g. auto-oriented Bangkok and Istanbul don’t have transit-oriented Shanghai’s CBD formation), dense auto-oriented city neighborhoods (e.g. North Tel Aviv), and transit-oriented low-density suburbia. This is the winning option.

In every (or almost every) city region, there’s a clear pattern to land use and transportation: the neighborhoods closer to the center have higher population density and lower car use than the ones farther away. Moreover, across city regions, there is such a strong negative correlation between weighted density and auto use that exceptions like Los Angeles are notable. That said, the extent of the dropoff in transit use as one moves outward into suburbia is not the same everywhere, and in particular there are suburbs with high transit use. This post will discuss which urban and transportation policies are likely to lead such suburbs to form, in lieu of the more typical auto-oriented suburbs.

What is a suburb?

Definitions of suburbia differ across regions. Here in Paris, anything outside the city’s 1860 limits is the suburbs. The stereotypical banlieue is in history, urban form, and distance from the center a regular city neighborhood that just happens to be outside the city proper for political reasons. It is hardly more appropriate to call any part of Seine-Saint-Denis a suburb than it is to call Cambridge, Massachusetts a suburb of Boston.

So if Seine-Saint-Denis is not a suburb, what is? When I think of suburbia, my prototype is postwar American white flight suburbs, but stripped of their socioeconomic context. The relevant characteristics are,

  • Suburbs developed at a time when mass motorization was widespread. In the US, this means from around 1920 onward in the middle class and slightly later in the working class; in the rest of the developed world, the boundary ranges from the 1920s to the 1960s depending on how late they developed. Note that many stereotypical suburbs were founded earlier, going back even to the 19th century, but grew in the period in question. Brookline is famous for refusing annexation to Boston in 1873, but its fastest development happened between 1910 and 1930, straddling the 1920 limit – and indeed in other respects it’s borderline between a rich suburb and rich urban neighborhood as well.
  • Suburbs have low population density, typical of single-family housing. Aulnay-sous-Bois, at 5,100 people per km^2, is too dense, but not by a large margin. Beverly Hills, which has mansions, has 2,300, and Levittown, New York, probably the single best-known prototype of a suburb, has 2,900. The urban typology can mix in apartments, but the headline density can’t be dominated by apartments, even missing middle.
  • Suburbs are predominantly residential. They can have distinguished town centers, but as broad regions, they have to have a significant number of commuters working in the city. This rules out low-density central cities like Houston and Dallas (although their individual neighborhoods would qualify as suburbs!). It also rules out Silicon Valley as a region, which represents job sprawl more than residential sprawl.

The three criteria above make no mention of whether the area is included in the central city. Most of Staten Island qualifies as suburban despite being part of New York, but Newark fails all three criteria, and Seine-Saint-Denis and most of Hudson County fail the first two.

Where are suburbs transit-oriented?

I do not know of any place where suburban transit usage is higher than city center transit usage. In theory, this suggests that the best place to look for transit-oriented suburbia is the cities with the highest transit mode shares, such as Tokyo, Singapore, and Hong Kong (or, in Europe, Paris). But in reality, Singapore and Hong Kong don’t have areas meeting the density definition of suburb, and Tokyo has few, mostly located away from its vast commuter rail network. Paris has more true suburbs, but like Tokyo’s, they are not what drives the region’s high rail ridership. All four cities are excellent examples of high-density suburban land use – that is, places that meet my first and third definitions of suburbia but fail the second.

Instead, it’s better to look at smaller, lower-density cities. Stockholm and Zurich are both good models here. Even the central cities are not very dense, at 5,100 and 4,700 people per km^2. Moreover, both are surrounded by large expanses of low-density, mostly postwar suburbia.

Winterthur, Zurich’s largest suburb, is a mix of early 20th century and postwar urban typology, but the other major cities in the canton mostly developed after WW2. At the time, Switzerland was already a very rich country, and car ownership was affordable to the middle class. The story of the Zurich S-Bahn is not one of maintaining mode share through a habit of riding transit, but of running frequent commuter rail to suburbs that did not develop around it from the 1950s to the 70s.

In Stockholm, there is a prominent density gradient as one leaves Central Stockholm. I lived in Roslagstull, at the northern end of Central Stockholm, where the density is 30,000 people per km^2 and the built-up form is the euroblock. Most of the rest of Central Stockholm is similar in urban form and not much less dense. But once one steps outside the city’s old prewar core, density nosedives. City districts to the west and south, like Bromma and Älvsjö, go down to 3,000 people per km^2 or even a little less. A coworker who used to live in Kista described the area as American-style suburban. Beyond these city districts lie the other municipalities, which together form a sizable majority of the county’s population. Of those, a few (Solna, Sundbyberg) are somewhat above the density cutoff, but most are far below it.

In both Zurich and Stockholm, the city is much more transit-oriented than the suburbs. Stockholm’s congestion pricing was a city initiative; the suburbs banded together to oppose it, and eventually forced a compromise in which congestion pricing remained in effect but the revenue would be deeded to urban freeways rather than to public transportation.

And yet, neither city has a big transit use gradient – at least, not so big as Paris, let alone London or New York. Stockholm is expecting 170,000 daily metro trips from its expansion program, which barely touches Central Stockholm. Existing T-bana ridership on the suburban tails is pretty high as well (source, PDF-p. 13), as is ridership on commuter rail, which, too, barely touches Central Stockholm.

The structure of density

In my previous post, I complained that Los Angeles’s density has no structure, and thus public transit ridership is very low and consists predominantly of people too poor to buy a car. The situation in Stockholm and Zurich is the reverse. Density has a clear structure: within each suburb, there is a town center near the commuter rail station.

The histories of Zurich and Stockholm are profoundly different. Each arrived in its structure from a different route. In Zurich, the suburbs come from historic town centers that existed long before cars, often long before industrialization. 20th-century urban sprawl arrived in the form of making these historic villages bigger and bigger until they became proper suburbs. The geography helps rail-oriented suburbanization as well: the ridge-and-valley topography is such that urban sprawl forms ribbons served by commuter rail lines, especially in the southerly direction.

Stockholm’s topography is nothing like Zurich’s. There are water boundaries limiting suburb-to-suburb travel, but the same is true of New York, and yet Long Island, New Jersey, and Westchester are thoroughly auto-oriented. Instead, the structure of density came about because of government planning. Sweden built public housing simultaneously with the Stockholm Metro, so the housing projects were sited near the train stations.

This does not mean that the suburbs of Zurich and Stockholm are actually high-density. Far from it: the housing projects in the Stockholm suburbs are surrounded by a lot of parking and greenery, and the suburbs have extensive single-family housing tracts. However, the density is arranged to grade down from the train station, and there are small clusters of walkable apartment buildings in a small radius around each station. In Zurich the same structure came about with private construction and topography.

To the extent this structure exists elsewhere, it leads to higher low-density transit ridership too, for example in London and the Northeastern United States. Various West Coast American transit bloggers, like Jarrett Walker and Let’s Go LA, keep plugging the West Coast grid over the Northeastern hierarchy of density. But this hierarchy of suburbs that formed around commuter rail to the CBD produces transit ridership that, while awful by Continental European standards, is very good by American ones. Many of the suburbs in question, such as in Westchester, have 15-20% of their commuters choose transit to get to work.

Getting to higher numbers means reinforcing the structure of density and the transit that works in the suburbs, that is, regional rail (or a metro network that goes far out, like the T-bana, if that’s an option). Stations must be surrounded by development rather than parking, and this development should facilitate a somewhat transit-oriented lifestyle, including retail and not just housing. Jobs should be accessible from as many directions as possible, forming CBDs rather than haphazard town centers accessible only by road. Only this way can suburbia be transit-oriented.


  1. Untangled

    How could you talk about transit-oriented suburbs and not talk about the Copenhagen Finger Plan? That was the probably the first plan ever that envisaged transit-oriented suburbs in the auto era. It was the Finger Plan that pretty much provided inspiration to cities across the world in the auto age on how to build and provide useful transit in a car suburb. Stockholm and Zurich I’m sure are inspired by the Finger Plan, they probably implemented it better than Copenhagen too but the Finger Plan was the original plan for transit in the suburbs. In fact, one of the cities, and probably one of the few in the English-speaking world, that was inspired by Copenhagen was Sydney. Of course, it was badly implemented, but the Finger Plan has definitely left its mark on Sydney, it has a higher transit usage share than any other Australian city and any other North American metro area, except NY. Sydney looked at London firstly in the post-war era but they abandoned it in favor of a bastardized/North American-ized Copenhagen Finger Plan. So Sydney ended up with quite unique suburban development patterns especially around regional rail stations thanks to that stripped down Finger Plan, in the Australia/North America context at least. Other Australian cities stuck with a bastardized version of London on paper without much TOD around suburban stations, but it mostly just sprawled anyway so it was pretty much North American.

    But anyway, look up the Copenhagen Finger Plan. Even though other cities probably did transit-oriented suburbs better, it’s still worth drawing looking at the original plan of all the plans.

    • Alon Levy

      What should I be reading about the Finger Plan? Wikipedia has a very brief discussion. As I understand it, the idea was to concentrate suburban development near S-tog lines? I don’t know to what extent this was influential on Sweden – Stockholm’s commuter rail is way less developed than the S-tog, and instead the state built public housing on top of new-build metro lines.

      Also, same question re Sydney. I’d assume Sydney has structured density purely because it has such high regional rail ridership, but I don’t actually know what the urban layout there is.

      • Untangled

        Yes Stockholm’s regional rail is not as well developed as S-tog but you can still see corridors or “fingers” along the T-bana with some green wedges (I guess instead of a green belt) in between. Idk what to read tbh, I read about the Finger Plan a few years ago but didn’t keep track of what exactly I read, I can remember some things about it (which is why I raised it) but can’t remember what it was called. A lot of the principles, like putting suburban shopping malls and other places, not just residential even if the suburb was mostly residential, close to stations was a big part of it. It also planned subcenters near suburban stations. It was all about proximity to stations for everything, not just housing.

        That said a quick Google search brings up this document which skims through the principles between page 10-17.

        As for Sydney, it used some of the principles of the Finger Plan in building around suburban stations, the big exception was the lack of green wedges where a lot of the outright car-dependent development occurred, like Ryde for example, the train was near-ish to stations but just too far away at the same time. Car-dependent developments also occurred in areas not served by rail or high-frequency bus corridors at all. I’ll might write up more on what I think about Sydney or dig up some stuff when I have time.

        • Untangled

          *train was near-ish to stations

          Oops, sorry for the gibberish there. What I meant was that a lot of Ryde is near-ish to stations, as in at least 2km away but not quite close enough. So car-dependent housing in what would otherwise be a green wedge. The stations around Ryde are getting quite an apartment boom, but not Ryde itself, Meadowbank is full of them right now and the Macquarie Park area is going big as well.

    • Michael James

      The main thing that distinguishes the Finger Plan from simple default radial transit, is the “green fingers” between the radials. The TOD aspect is a natural consequence, though does benefit from explicit planning as per our earlier discussion of such places as Cergy, Poissy, Melun (and Evry) etc (or Milton Keynes I suppose). In fact, if there is one city that appears to conform to the Finger concept it is … you guessed it … Paris. It even has the five fingers represented by the 5 RER lines; the Wiki entry even speaks of it based on Regional Rail (which is the R in RER). This is more convergence than inspiration from Copenhagen (but I have the Robert Cervero book–ref#1 in the Wiki entry–so I’ll check it out when I get home today). By virtue of density of those proto-TODs in Ile de France, and their existence, grace of royal estates, Paris-Ile-de-France is happily endowed with huge green fingers, and I don’t mean Bois de Boulogne or Vincennes but Meudon, Marly, Montmorency, L’isle-Adam, Rambouillet (220km2), Fontainebleau (250km2), St-Germain-en-Laye (35km2), Sénart (30km2) and a dozen others. By whatever sequence of historical events London didn’t have the same thing and, very late in the day, created a so-called Green Belt to provide some relief to urban sprawl (some argue it just pushed sprawl even further out). By the time urban planners got any traction most big world cities were beyond its implementation though arguably Tokyo had its opportunity post-war, but blew it big time.

      • Alon Levy

        The big difference is that suburban population density here is high. Aulnay is comparable to Stockholm proper, and Saint-Germain-en-Laye minus the forest is a hair denser than Bromma or Levittown. The built-up form here is continuous urbanization in the city, Petite Couronne, and innermost areas of the Grande Couronne, with some internal parks like Bois de Vincennes. In this way France is a lot like the US and Japan, except denser all around than the US but less dense than Japan, and unlike Britain and Canada (with their green belts) or the Netherlands, Germany, and Austria (where there are sharp boundaries between municipalities).

        You only start seeing ribbon-style development really far out, like along the RER B past Massy, or downriver vaguely near Transilien J. But up the Marne there’s not that much greenery between the RER A and Transilien P. Closer in it’s one blob of density, which is why they keep adding suburban Metro extensions and the M15 and M16 orbitals.

        The farther-out examples of TOD are more dots than ribbons. Marne-la-Vallee clusters around MLV-Chessy and Val d’Europe, and doesn’t reeeeally form a ribbon around the RER A. Cergy, same thing. Evry has a forest to its east, but to the west there’s continuous sprawl. Melun and Meaux are historic town centers that suburbanized, like Wintherthur but a lot denser.

        • Michael James

          I don’t disagree. As I wrote, a lot of Paris and Ile de France development has been fortuitous. OTOH, while I haven’t examined London’s history from this angle, in France I suspect the Revolution and continuing republican sentiment for the intervening period, kept all that green space–former royal parks and hunting forests–from being sold off to developers, ie. kept it as public space. Further, as you noted, existing development, ie. regional towns, were already dense and this was a big advantage for modern big-city development compared to England and the Anglosphere, where lower-density single homes or terrace-housing was preferred. (One theory as to why posits that on mainland Europe security issues prior to modern nation states led to compact and sometimes fortified development even in small villages was the norme.)

          Re the Marne, yes it is heavily industrial or rather uninteresting flat farmland. No accident that this area encompasses the infamous banlieus of underprivileged Paris, as it never had the royal palaces and their parks and forests like the three other cardinal directions had/have. You have to go beyond Meaux to find chateaux etc. OTOH, the upper Seine is pretty unrelenting industrial too, just that with Senart and Fontainebleau it had some protected regions.

          By the way, remember in that earlier comment I talked about sailing “my” peniche up Canal de l’Ourq (thru Seine-St-Denis then Seine-et-Maarne) to Bois Belleau/Chateau Thierry? Alas, no. I was taking poetic liberty–in addition to not having a peniche. First, the canal guides warn that this stretch is not very interesting. Second, it doesn’t turn more interesting until after Claye-Souilly to Meaux, and this part (the so-called Petite Section) is not navigable by any serious boat and certainly not a peniche; in fact depending on that summer’s rainfall it may not get past Sevran, 13km before Claye-Souilly. The only way for a peniche to get to Meaux and then Chateau Thierry, is on the river Marne itself.
          The Wiki entry on Copenhagen’s Finger Plan is an abbreviated version of Cervero’s chapter 5.

    • Si Hollett

      “a bastardized version of London on paper without much TOD around suburban stations”

      A very bastardized version of London – most of London’s suburbs grew around the stations with the design orientated around them. This was for the very simple reason that the rail companies were the ones building the houses initially. If you look at maps through the inter-war years, the areas around stations urbanise and then that spreads out to the arterial roads that were being built at the same time.

      Even in my exurb with its mostly post-war developments not owned by the railways, everything was designed with walking to the station as a key priority (so lots of footpaths towards the station), and driving was made relatively difficult – lots of cul-de-sacs and long-ways round, few exits from estates by road. But, like most of the rest of Metroland (and the clue is in the name that it’s TOD), the railway doesn’t serve the majority of people’s current commuting patterns (Outer West London & the bit just over the boundary from it is its own travel-to-work area), and the infrastructure that does is inadequate for the flows, and mostly car-reliant, and thus congestion.

  2. James Sinclair

    “I do not know of any place where suburban transit usage is higher than city center transit usage.”

    The unique case would be the suburban college campus. New Brunswick, New Jersey. Davis, California. maybe Ann Arbor?

    • Alon Levy

      I wouldn’t call these places suburbs – they miss the third criterion. They’re centers of small metro areas. Middlesex County, New Jersey is a net recipient of commuter flows measured by income; like Silicon Valley, it’s an example of job sprawl rather than residential sprawl.

  3. dhdaines

    The South Shore suburbs of Montréal are fairly heavy transit users. Brossard in particular has a transit mode share that would be the envy of most cities in the USA:

    Until 2022 or so the transit system in question will continue to rely on a team of workers who manually place orange cones on the Champlain Bridge to block off a bus lane every morning and afternoon. As you say, it all comes down to a very high job density in the city centre, but also the extremely limited road connections to it.

    • dhdaines

      (actually that’s not true, we’ll get a new bridge next year, but no LRT on it for a while still)

  4. ckrueger99

    Delaware County, Pennsylvania (of Philadelphia). Has light rail and buses for the working class; regional rail for the upper.

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  8. Miguel

    The vast majority of Americans live in suburbs (not cities), and it is rare for the anchor city of metro areas to have larger population than surrounding suburbs. Like differences overall in suburbs, there are many densely populated, often older suburbs of American cities with transit. The three most densely populated municipalities in Illinois, for example, are all western suburbs of Chicago (which is 4th most densely populated in state). Many of those suburbs have heavy rail, urban rail (subway/elevated trains), bus systems (plural) and stops for national rail too. There are also smaller cities, many old, which have now blended into metro area sprawl. Chicago area is unique, like NE US, with many transit options, including the remaining interurban in the US (to/from South Bend, Indiana). The notion of suburbs being far away places devoid of commerce or population, is outdated. Furthermore, most Millennials (generation often discussed)also live in suburbs in greater numbers. covid has made the exodus to suburbs from cities grow.

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