As production becomes increasingly clean and knowledge-based, as our urban economies tip dramatically to service industries, as racism and ethnic animosities ebb, and as the model of mixed use becomes more and more persuasive and visible, cities are in a position to dramatically rethink zoning as a medium for leveraging and usefully complicating difference, rather than simply isolating it.
Raskin, in his essay on variety, suggested that the greatest flaw in city zoning is that it permits monotony. I think this is correct. Perhaps the next greatest flaw is that it ignores scale of use, where this is an important consideration, or confuses it with kind of use.
Work uses suggest another bugaboo: reeking smokestacks and flying ash. Of course reeking smokestacks and flying ash are harmful, but it does not follow that intensive city manufacturing (most of which produces no such nasty by-products) or other work uses must be segregated from dwellings. Indeed, the notion that reek or fumes are to be combated by zoning and land-sorting classifications at all is ridiculous. The air doesn’t know about zoning boundaries. Regulations specifically aimed at the smoke or the reek itself are to the point.
Every attempt to cul-de-sac city streets, to change traffic patterns in favor of pedestrians, or to narrow street ends is met with the same howl of protest from the authorities: this will increase congestion because urban traffic is a zero-sum game. Any reduction in volume in one place in the city will inevitably be accompanied by a rise in traffic somewhere else.
This claim is fallacious: the true corollary is the opposite. In case after case, a reduction of the space available for vehicular traffic has simply resulted in the reduction of traffic overall.