Network Analysis of Intra-urban Public Transport

A Case Study of Municipal Bus Service in Kyoto

Abstract

In this paper, the structure of bus service network is analysed as a system of bus routes connecting a pair of unit areas. This research is based on graph theory, in which transport networks are interpreted as systems of connections between pairs of places.
The paper is concerned with the region served by the municipal bus service of Kyoto City. This consists of 164 unit areas, including 162 mesh areas and two secluded areas among mountains, Onogo, and Yase-Ohara (Fig. 1).
A connectivity matrix C is defined on the basis of the existence of the connection by a bus route between any pair of unit areas. Then, a shortest path matrix D₄ is derived from C. The sum across any row of D₄ indicates the accessibility from one area to all other areas (Fig. 2). The peak of this accessibility is at the city center of Kyoto, Shijo-Karasuma, and ridge lines radiate from there along Shijo street and Karasuma avenue. The matrix L⁴ is derived from the matrix L, with elements of numbers of services, whose pattern of accessibility resembles that of D₄ (Fig. 3).
The accessibility index of the matrix L⁴ between any pair of areas is multiplied by the population indeces of the two areas, and the resulting matrix is defined as interaction between the two areas. Among these interactions of an area, the largest is specified as a link comprising the nodal structure of the region (Fig. 5). The resulting nodal structure indicates that a great majority of the unit areas are oriented to the city center, and that this region lacks an intervening level of centers. This means that, in the scale within the city, there is no system covering changes between rapid mass-transit, such as trains, and municipal bus service.