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.