The Four Quadrants of Cities for Transit Revival
Cities that wish to improve their public transportation access and usage are in a bind. Unless they’re already very transit-oriented, they have not only an entrenched economic elite that drives (for example, small business owners almost universally drive), but also have a physical layout that isn’t easy to retrofit even if there is political consensus for modal shift. Thus, to shift travel away from cars, new interventions are needed. Here, there is a distinction between old and new cities. Old cities usually have cores that can be made transit-oriented relatively easily; new cities have demand for new growth, which can be channeled into transit-oriented development. Thus, usually, in both kinds of cities, a considerably degree of modal shift is in fact possible.
However, it’s perhaps best to treat the features of old and new cities separately. The features of old cities that make transit revival possible, that is the presence of a historic core, and those of new cities, that is demand for future growth, are not in perfect negative correlation. In fact, I’m not sure they consistently have negative correlation at all. So this is really a two-by-two diagram, producing four quadrants of potential transit cities.
Old cities
The history of public transportation is one of decline in the second half of the 20th century in places that were already rich then; newly-industrialized countries often have different histories. The upshot is that an old auto-oriented place must have been a sizable city before the decline of mass transit, giving it a large core to work from. This core is typically fairly walkable and dense, so transit revival would start from there.
The most successful examples I know of involve the restoration of historic railroads as modern regional lines. Germany is full of small towns that have done so; Hans-Joachim Zierke has some examples of low-cost restoration of regional lines. Overall, Germany writ large must be viewed as such an example: while German economic growth is healthy, population growth is anemic, and the gradual increase in the modal split for public transportation here must be viewed as more intensive reuse of a historic national rail network, anchored by tens of small city cores.
At the level of a metropolitan area, the best candidates for such a revival are similarly old places; in North America, the best I can think of for this are Philadelphia, Boston, and Chicago. Americans don’t perceive any of the three as especially auto-oriented, but their modal splits are comparable to those of small French cities. But in a way, they show one way forward. If there’s a walkable, transit-oriented core, then it may be attractive for people to live near city center; in those three cities it’s also possible to live farther away and commute by subway, but in smaller ones (say, smaller New England cities), the subway is not available but conversely it’s usually affordable to live within walking distance of the historic city center. This creates a New Left-flavored transit revival in that it begins with the dense city center as a locus of consumption, and only then, as a critical mass of people lives there, as a place that it’s worth building new urban rail to.
New cities
Usually, if a city has a lot of recent growth from the era in which it has become taken for granted that mobility is by car, then it should have demand for further growth in the future. This demand can be planned around growth zones with a combination of higher residential density and higher job density near rail corridors. The best time to do transit-oriented development is before auto-oriented development patterns even set in.
There are multiple North American examples of how this works. The best is Vancouver, a metropolitan area that has gone from 560,000 people in the 1951 census to 2.6 million in the 2021 census. Ordinarily, one should expect such a region to be entirely auto-oriented, as most American cities with almost entirely postwar growth are; but in 2016, the last census before corona, it had a 20% work trip modal split, and that was before the Evergreen extension opened.
Vancouver has achieved this by using its strong demand for growth to build a high-rise city center, with office towers in the very center and residential ones ringing it, as well as high-density residential neighborhoods next to the Expo Line stations. The biggest suburbs of Vancouver have followed the same plan: Burnaby built an entirely new city center at Metrotown in conjunction with the Expo Line, and even more auto-oriented Surrey has built up Whalley, at the current outer terminal of the line, as one of its main city centers. Housing growth in the region is rapid; YIMBY advocacy calls for more, but the main focus isn’t on broad development (since this already happens) but on permitting more housing in recalcitrant rich areas, led by the West Side, which will soon have its Broadway extension of the Millennium Line.
Less certain but still interesting examples of the same principle are Calgary, Seattle, and Washington. Calgary, a low-density city, planned its growth around the C-Train, and built a high-rise city center, limiting job sprawl even as residential sprawl is extensive; Seattle and the Virginia-side suburbs of Washington have permitted extensive infill housing and this has helped their urban rail systems achieve high ridership by American standards, Seattle even overtaking Philadelphia’s modal split.
The four quadrants
The above contrast of old and new cities misses cities that have positive features of both – or neither. The cities with both positive features have the easiest time improving their public transportation systems, and many have never been truly auto-oriented, such as New York or Berlin, to the point that they’re not the best examples to use for how a more auto-oriented city can redevelop as a transit city.
In North America, the best example of both is San Francisco, which simultaneously is an old city with a high-density core and a place with immense demand for growth fueled by the tech industry. The third-generation tech firms – those founded from the mid-2000s onward (Facebook is in a way the last second-generation firm, which generation began with Apple and Microsoft) – have generally headquartered in the city and not in Silicon Valley. Twitter, Uber, Lyft, Airbnb, Dropbox, and Slack are all in the city, and the traditional central business district has expanded to South of Market to accommodate. This is really a combination of the consumption-oriented old-city model, as growing numbers of employees of older second-generation firms chose to live in the city and reverse-commute to Silicon Valley, and the growth-oriented new-city model. Not for nothing, the narrower metropolitan statistical area of San Francisco (without Silicon Valley) reached a modal split of 17% just before corona, the second highest in the United States, with healthy projections for growth.
But then there is the other quadrant, comprising cities that have neither the positive features of old cities nor those of new cities. To be in this quadrant, a city must not be so old as to have a large historic core or an extensive legacy rail network that can be revived, but also be too poor and stagnant to generate new growth demand. Such a city therefore must have grown in a fairly narrow period of time in the early- to mid-20th century. The best example I can think of is Detroit. The consumption-centric model of old city growth can work even there, but it can’t scale well, since there’s not enough of a core compared with the current extent of the population to build out of.



