Homogeneity Analysis and Planning Studies

Aggregation bias has been recognized as a problem when trying to define travel demand and is documented in detail for a subarea of Buffalo. This subarea consists of three adjacent square-mile transportation zones, varying from white to black in racial composition. The zones are shown to differ in those household parameters usually associated with travel generation: income, auto ownership, and related parameters including housing value and job type. In the zones considered, auto ownership is approximately one-half the city average, yet satisfaction of travel demand is not consistently good or poor throughout the zones. The primary trip purpose, work trip, is more readily satisfied by use of public transit in the white area than in the black area. A microstudy based upon block statistics underlines the inherent bias brought about by macrostudies. To refine such studies a new quantitative concept of homogeneity and continuity is defined and applied to the study area. The paper concludes with a description of how microstudy analysis can serve as a real input to macroplanning.