Schlomo 'Solly' Angel is a world renowned urbanist and author of countless books including Atlas of Urban Expansion, Planet of Cities and Tale of Scale. He is adjunct professor at New York University (NYU) and senior research scholar at the NYU Stern Urbanization Project, where he leads the Urban Expansion initiative. He has advised the United Nations, the World Bank, and the Inter-American Development Bank (IDB).
So when Solly Angel observes that across the United States that "the great majority of workplaces (are) now dispersed outside CBDs, employment sub-centers or live-work communities, and (are) beyond walking or biking distance" he is saying so as a well-informed global expert.
He goes on to conclude that as a result "increasing the productivity of American cities requires a sustained focus on meeting the travel demands of the great majority of commuters rather than on improving mobility at large or on transportation strategies focused on CBDs, employment sub-centers, or live-work communities."
Essentially, the point he is making is that few cities observe the deterministic overlays imposed by urban planners for the sake of convenient analysis. The monocentric model (a high density CBD to which a majority of workers commute from outlying dormitory areas) he claims almost never exists in reality (although oddly, this model describes widely held prejudices about our own urban form).
The poly-centric model (with multiple centres) is he says equally more often described in theory than in practice. There are various other urban models, including what he calls "the maximum disorder model" (which I love the sound of) but the one that he argues best describes the majority of US cities is the "constrained dispersal model" where "the great majority of jobs are dispersed throughout the metropolitan area and where workers and workplaces in a metropolitan-wide labor market adjust their locations to be within a tolerable commute range of each other." Makes sense, hey?
In a nutshell, because we live and work in largely randomized locations across cities, a focus on urban productivity needs to acknowledge this reality and try to create transport systems that cater for the majority of commuters, not just a proportion who can be serviced by public transport in high density cores. In his words:
While we do not have to accept this state of affairs as the best of all possible worlds, as Voltaire's Candide would have it, we do have to acknowledge it and to understand that the future of our cities is path dependent: the cities of the future will be variations on the cities of today and, barring catastrophes and calamities of one kind or another, any changes in their spatial structure and their built form are likely to be gradual and marginal, building upon their existing spatial structure. The same observation also applies to commuting patterns: most commuting patterns are quite likely to be between dispersed residences and dispersed workplaces for a long time to come.
In Australia, much like the USA, CBDs do not dominate as metro wide employment hubs (as they might in a hypothetical mono-centric model). They are significant but not dominant. In some cases, their significance is eroding – not because they are shrinking, but because the suburban economy is growing faster. In Sydney and Melbourne for example, inner city jobs (being the CBD plus surrounds, described as the SA3 by the ABS) represent 22% and 21% of metro wide jobs respectively. In Brisbane the figure is lower – with the inner city representing 14% of regional jobs. Interestingly, while Brisbane's inner city added 12,802 jobs (full and part time and casual) in the 2011-2016 period (growing by 7%) the Greater Brisbane region added nine times that number at 112,517 jobs in the same period, growing faster at 12%.
Much like the USA, our major cities mostly fit Solly's "constrained dispersal" model. Plus, with the two fastest growing future industries being health and education, that pattern of dispersal is likely to increase over time. So to ensure our cities remain economically productive, urban transport policy should ideally support the efficient movement of the greater majority of people from home to work and during work. Cycling, walking, and traditional modes of public transport are suitable for some of the working population, but nowhere near a majority. For the majority of workers, the rational transit solution is the car.
Which makes the relentless public policy and media assault on the private car a strange thing. For the majority of workers in dispersed urban locations, it offers door to door convenience, it is on demand (ready when they are), it is comfortable (and often air conditioned), and generally quite affordable. As a transport choice, it also generates substantial government revenues via taxes (fuel excise, registration fees, etc) compared with public transport which consumes a great deal more in subsidies than it generates via the fare box.
We have fallen into a habit of blaming congestion on the car but we also need to accept that more people (a bigger population) trying to get around on the same road space is - mathematically and inevitably - going to mean more congestion. Public transport has an important role to play but its ability to "solve" congestion has been oversold. Unless worldwide patterns of employment dispersal are suddenly and radically reversed and the monocentric urban model materializes overnight, PT will forever be limited by its convenience for the minority of urban workers with jobs in urban cores or high density suburban centres. Outside this, the 80% of the remaining urban workforce will continue to use cars as a rational and affordable choice. (Additionally, intra urban freight will continue to be totally reliant on private delivery vehicles using the road space).
The horizon for the private car is also not bleak, as some might suggest. Advances in driverless technology, car sharing and other innovations in urban mobility that revolve around better ways to make use of private vehicles (which for many sit idle 20 out of 24 hours) are worthy of exploration, but receive little public policy attention (or investment). So far anyway.
Addressing urban congestion therefore should require a balanced policy which accepts the critical role played by private transport and the road network, along with the critical role played by public transport. Demonising the car, or suggesting that it can be largely replaced by walking or cycling or PT for a majority of the population, is delusional given the spatial reality of our urban economies. If this thinking finds its way into public policy practice, it goes from delusional to dangerous.
You can read Solly Angel's work on Commuting and the Spatial Structure of American Cities, via the link below.