CHARACTERISTICS OF METRO NETWORKS AND METHODOLOGY FOR THEIR EVALUATION

Presented in this paper are the results of research on metro (rapid transit) networks, focusing on their geometric characteristics. The object is to define the most important measures, indicators, and characteristics of geometric forms that can improve the present predominantly empirical methods used in metro network planning and analysis. Several measures of metro network size and form, including length, number of lines, and stations, which express the extensiveness of the system, are selected; they are also needed for derivations of various indicators. A number of selected indicators are then presented. These represent the most effective tool for network comparison because most of them are independent of network size. Several indicators relating metro network to the city size and population express the degree of adequacy of the network to meet the city's needs. Based on experiences from a number of metro systems, characteristics of different types of lines (radial, diametrical, circumferential, and other) are defined. These allow evaluation of network types, such as radial-circumferential versus grid networks. An analysis of metro networks in 10 different cities is presented to illustrate the applications of theoretical and empirical materials; several basic measures and indicators of these networks have been computed and analyzed. The scope of quantitative elements, analyses of types of lines, and descriptions of networks are limited because of space constraints, but they illustrate the methodology that can be used, in a more comprehensive way, for a number of different analyses of metro networks, their designs, or their extensions.