Suburbia Requires a New Transportation Technology

We built the first suburbs based on passenger trains, the next set based on grade-separated urban rail, and a third set based on streetcars. Then we did it again with the automobile, and again with the limited access highway. In every case, it was a new transportation technology making previously inaccessible land more accessible and making it accessible in such volume that an urban development pattern built on cheaper-then-previous-urban land happened. Each time, over time, the flood of new resource was exploited, but further exploiting it required greater and greater investment, leading to declining returns, until things petered out, and the financial of the new development pattern no longer worked. 

No one recognizes this today, because for three generations we had a massive subsidy regime where we taxed gasoline to pay for new limited access highway miles. That subsidy regime went bust in 2008, and the last fifteen years have been a scramble to prop it up. Because there is a lot of money invested in suburbia continuing. There are entire industries predicated on turning raw land into suburban houses, and entire polities dependent on that process, and there is an awareness if that engine stops running, our entire economy might tank. (Japan's did. China's is). 

So the smart money gets that another round of suburbia requires a new transportation technology. So there is a lot of investment in both flying cars and connected and autonomous vehicles*. Both are oversold, because the people developing both are trying to recruit enough investment money to actually develop a saleable product, so they overstate the benefits their product will provide. The most basic way they do that is talking about how much time drivers will save, which sounds great to drivers. But to anyone involved in infrastructure (planners, transportation economists, engineers), everyone is very clear that driver time is not the limiting factor in our transportation system but rather road capacity, and driver-time has heretofore been a limitation on driver utilization of road capacity. So even if every vehicle becomes a CAV, traffic will not disappear, and indeed, will likely grow worse.

I say new technology because old technologies aren't going to save us. We are already familiar with their characteristics, with their limitations, and make use of them where appropriate and efficient. But having another round of suburbanization relies on a transportation technology sufficient to make a massive volume of previously inaccessible land available for development. 

My personal bet is on flying cars, simply because they don't have right-of-way costs. But flying cars have the same issues as automobiles, if not worse: they take up a lot of space. So they may be useful at the periphery, they don't solve the problem of making trips between two regimes: the low-D autocentric regime, and the high-D geometry-hates-cars regime. 

Urbanization and Transportation

The spatial arrangement of urbanization is determined by trade in whatever is valuable. If that thing is rare or dense, you build cities at natural crossroads. If it's bulky, you get cities near navigable rivers. If it relies on combining things, you build around ports. If you rely on bulk inputs, your build at the fall line. 

Urban Regimes

It's critical to recognize that for travel behavior there exist different urban regimes, which can be defined in terms of the "D variables" (Density, Diversity, Design). And in one regime, it's painfully absurd to do anything but drive. Distances are long, routes are indirect, all the infrastructure is auto-centric, parking is plentiful and free. And that regime characterizes 95% of the urban area. But when distances are shorter, routes are direct, you've got infrastructure that is safe and humane for people not in cars, and parking is painful. Useful transit exists. And in the latter regime, that car is no longer the most efficient mode of transport.

And when that happens, we should stop privileging the automobile as the most efficient mode. Even conceptualizing what it would be like to privilege another mode is astonishingly powerful, because it rapidly leads to a catalogue of things we have to do for cars: the space we provide, the risks we tolerate, the funding we provide, the denial of access, the regulation of unrelated matters (Daylight Savings Time), the distortion to every development, etc. And we have to ask: "If cars are no longer the most efficient mode, why are we spending millions prioritizing the movement of cars, and mandating everyone else spend millions providing for the storage of cars"?

The simple answer is that for most trips, one end of a trip lies in the auto-centric regime, and it's a choice between imposing costs in the smaller area where cars are less efficient, or in the larger area, where cars are more efficient. And benefitting the suburbs to the detriment of central cities was official US policy for decades. It wasn't until the "Urban Transportation Problem" hit, when congestion outstripped road building, that thoughtful people realized building their way out of congestion was impossible--traffic was growing faster than the capacity to pay for it, even as the cost of paying for it became exponentially higher. And then we started building rapid transit. (And saving older transit systems). 

Geometry hates cars

The simple fact is that geometry hates cars. Cars are an amazing way to travel, and for most places in America, nearly the only way to travel. But cars take up a lot of space (most of which is parking). Most places, that's a non-issue: We've mandated a 30-year supply of both roads and parking. But for anyplace that existed prior to those mandates (any main street, downtown or CBD more than 50 years old), those mandates didn't exist, and adding either lanes or parking requires demolishing buildings. 

We all understand that adding a lane for a block doesn't do anything. If it's going to do any good, it's got to go on for a good long while. So adding a lane for five miles requires acquiring five miles worth of front yards. And fighting with a few thousand property owners. And that's very difficult to do these days--lawsuits and lawsuit-induced delays are an inevitability. 

I've written previously about the extraordinary racism of urban highways, but here is the nut: the land was never cheap, the marginalized people it was taken from just lacked the legal rights to effectively contest it, and get a fair price for what was being taken. Where they did (DC) you'll find a near-complete absence of urban highways. 

Cars require a lot of land. They aren't making any more land. With fixed supply, as the demand rises, so does the price. So every bit of land devoted to cars is expensive and mandating that land be devoted to cars is just imposing a cost that, given free choice, people would not choose to pay.