COMPARISON OF SUSTAINABILITY BETWEEN PRIVATE AND PUBLIC TRANSPORT CONSIDERING URBAN STRUCTURE

It is said that the car is convenient but consumes high-energy per passenger, while public transport is an environmentally friendly mode but needs high cost of investment and management. However, this view does not take account of urban structure such as population size and density. For instance, higher population density would cause congestion and consequent inconvenience for car usage. This may shift demand to public transport use. On the other hand, in a lower density of urban area, public transport attracts only a small passenger demand and thereby accounts for a high-energy consumption per passenger than private cars. The urban structure therefore can be the dominant factor for determining the effectiveness of urban transport. The urban structure is affected by the provision of transport infrastructure and its service level. In classical urban economic models, the location of agents and urban shape vary depending on the transport conditions. Therefore, the urban structure and transport effectiveness are inter-dependent. Even if the population size and density is the same, the efficiencies of private and public transport might be different due to the urban structure because of their historical pattern of land use and transport development. In this paper, we present the interaction between urban structure and transport using a simple urban-transport model. We also examine the sustain ability, measured by economic efficiency and environmental impact, of private and public transport in a hypothetical urban space. In this regard, it is specially focused on the path dependence of urban-transport interactions, and showed the possibility of multiple urban and transport situations. Several policy implications are proposed for utilizing the results of the models.