On Engineering Urban Densification

City planning in America began as a Progressive Era exercise, intended to pre-serve property values and implicitly incorporate the social norms of officials and planners. Over time, rigid zoning was replaced by flexibility, accompanied by opaque bargaining between localities and developers. Still, even in vibrant large cities, homeowner preferences for low density largely prevailed over attempts to enhance agglomeration through increasing density. The effect is to reduce economic opportunity for individuals, and cities less prosperous.One method of increasing agglomeration is the imposition of densification, utilizing the assembly of transient coalitions that could impose grand bargains between alderman and strong mayors. Expert planners would devise detailed quotas for desirable and undesirable uses in different parts of the city, and recipients of favorable zoning would receive regulatory property that is locked in place by procedural and constitutional requirements. Roderick Hills and David Schleicher advocate this approach in City Replanning.This Article reviews the history of idealistic, and later pragmatic, comprehensive planning and zoning. It then analyzes the case for agglomeration, and how it might be obtained through density mandates. The Article subsequently reviews undesirable consequences of such mandates. It asserts that grand bargains attenuate democratic decisionmaking, significantly reinforce the perceived evils of the current system, and are apt to be ineffective