The subsidized roads/zoning feedback loop

I've been reading this fascinating article by William Fischel at Dartmouth about the history of zoning in America. The ultimate conclusion is that zoning is a political manifestation of home value insurance and that such insurance might be valuable in lessening the exclusionary impacts of zoning, but the history that the author gives is much more interesting.

The most interesting conclusion he has is that zoning was a direct response to the freedom of the automobile, bus, and freight truck. Whereas previously the rich (always the most fervent advocates of zoning, both then and now) were secluded from the city and inner-suburb riff-raff by higher subway fares and the expense of owning and operating a car, the author argues that the coming of trucks and buses in the 1910's is what really did in unregulated land use. Apartment blocks were the bane of every wealthy single-family homeowner's existence, and they were seen as lowering housing prices and destroying the character of a neighborhood.

All well and good – an explanation that rings true even today – but there's something that I find lacking in it. Namely, the car, bus, and truck weren't the only ingredients in this whole shift: there was also the not insignificant matter of the roads they ran on. The capital costs of laying streetcar tracks were financed by sale of houses and real estate around the streetcars, and the operating costs were financed through user fees.* The roads, on the other hand, were, at this point in time, both constructed and maintained by various levels of government. Though "libertarian" writers from the Cato Institute would have you believe otherwise, the government spending binge on roads preceded the nation's first state fuel tax (passed in Oregon in 1919) by at least half a decade. As early as 1913, the costs of building roads were already weighing on state and local budgets, who didn't fund those projects out of dedicated fuel taxes. The federal government didn't start collecting user fees in the form of fuel taxes until 1932, despite passing its first highway bill in 1916, and really getting into the highway funding game with the Federal-Aid Highway Act of 1921.

If the increased mobility afforded by buses and trucks is seen as a direct result of subsidized roads, then zoning is as well. Sadly, not only was zoning driven by the subsidized roads, but now zoning begets even more roads. Populations grow but legislated densities rarely do, so the natural tendency is to build outwards rather than upwards to accommodate the change. Though our current road system may be more-or-less pay-as-you-go, looking somewhat like a self-sustaining independent free market creation, the truth is that the current patterns are only sustainable because of the zoning regulations that spread people far enough out that everyone's driveway doesn't have to open into a six-lane highway. Were the government forced to provide roads for any density that required it, it would be overwhelmed with the costs of constantly widening streets.

* The land use situation wasn't completely laissez-faire. Real estate developers (i.e., streetcar magnates) often used their political connections to get the government to grand monopolies on streetcar lines, creating a sort of de fact exclusionary zoning code.