Optimal spacings for a rectangular grid transportation network—I: A hierarchy structure

Abstract

An idealized rectangular grid transportation network is considered for serving a uniformly developed urban area in which trip origin-destination characteristics are translationally symmetric. The object is to choose the spacings between different types of roads so as to minimize the sum of travel and construction costs, subject to the hypothesis that travelers choose routes of (approximate) minimum travel costs. It is shown that rectangular grid systems are, generally, superior to square grids and that an efficient network will contain a hierarchy structure. Estimates are made of the spacings between roads in each direction and in each hierarchy.