Formation of Hub Cities

Abstract

Many cities are located on rivers or coasts. This paper argues that such cities developed as transportation hubs or markets for interregional trade, since these locations provide better access (lower marginal transportation costs) to other regions. Local products are collected at such hubs, and interregional trade then takes place among these transportation hubs. As the volume of trade between hubs increases, more workers are needed in order to meet labor demand for shipping and handling commodities, resulting in population agglomeration at such hubs. This paper constructs a simple three location-identical consumer model, in which transportation hub and population agglomeration emerge endogenously. In contrast with much of the literature on city formation, we introduce no economies of scale into the model. Markets are assumed to be perfectly competitive and complete. Since prices are determined in equilibrium, transportation costs and routes are simultaneously determined in the system. Population agglomeration occurs solely because of location-specific production technologies (which generates gains from trade) and the differences in transportation technologies among locations (which determines the transportation routes). It is shown that a hub city emerges when transportation technologies are heterogeneous enough.