NYC-WTC_000187725

NYC 9/11 Public Portal Document

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The 1960s and 1970s were a period of vigorous experiment with both of these types of model. The Lowry model was extended and improved, and was widely used in many planning offices, especially for structure planning in Great Britain. (This model had never postulated a monocentric city.) Efforts were made to convert the Wingo-Alonso approach to a form of linear programming — first without employment centers by Herbert and Stevens, and later with multiple centers by the NBER project, centered at Harvard University. Meanwhile McFadden and other economists developed the theory of discrete choice, and thus provided a basis for gravity­ like models. The stage was now set for a unification of these two streams of residential theory and models, together with a modern version of retail trade location. This unification proceeded on both a practical and a theoretical level, the practical effort being based on Lowry, and the theoretical on Wingo-Alonso. The Lowry model tradition reached its peak in the development of an integrated set of models and the addition of an industrial location model in the work of Stephen Putman at the University of Pennsylvania. However, Putnam’s model, like Lowery’s, did not include rents. At the same time, a Cambridge architect-planner, Marcial Echenique, extended the Lowry model in many directions. He too added a model of industrial location, and he incorporated a full scale transport demand model and used rents (largely fictitious) to arbitrate the competition for space and prevent unrealistic overcrowding. Both of these models have been operational successes, and have been widely applied under their authors’ supervision in several metropolitan planning efforts. Echenique’s work most closely approximates work deriving from the Wingo-Alonso tradition. Anas integrated the Wingo-Alonso theory with McFadden’s discrete choice theory to allow for diverse choice behaviors and multiple employment centers, while preserving the expression of a true economic theory of land prices as the basis for reaching equilibrium. This equilibrium represents a kind of outer limit of the benefits which can be achieved by a residential plan, assuming that all households ultimately find their best achievable location. The equilibrium depends, however, on all the surrounding decisions about zoning, transport facilities, and industrial (non-population- serving industry) employment. The current formulations of the model, presented as NYREG in this Handbook, have adopted direct measures of the benefits of a transport plan in terms of the economic concepts of consumer and producer surpluses. There is a significant benefit for planners in the fact that both of these classes of models are readily computable, given their careful formulations and present computer technology. In NYREG’s case, this computability depends on the equilibrium nature of the model, and the fact that its formulations are mathematically exact as well as being well-structured for' modern super computers or desk-top workstations.

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