Source: adapted from Friedmann, J. (1966) Regional Development Policy: A Case Study of Venezuela, Cambridge, Mass.: MIT Press.
The conventional core-periphery model of development tries to represent the emergence of an regional urban system in four major stages which goes on par with the development of regional transport systems. From an initial process that favors the setting of spatial inequalities, these are eventually reduced and a functionally integrated urban system emerges.
- Stage 1 (Pre-industrial). The pre-industrial (agricultural) society, with localized economies and a small scale settlement structure. Each settlement is fairly isolated, activities are dispersed and mobility is low. There are limited differences between spatial entities in terms of levels of economic development.
- Stage 2 (Transitional). The concentration of the economy in the core city begins as a result of innovation. capital accumulation and industrial growth. The specific reasons behind this concentration are often not too clear, location (better access) being a significant factor, but the fact remains that a dominant center emerges within an urban system to become its growth pole. Trade and mobility increase, but within a pattern dominated by the core even if the overall mobility remained low. Among the numerous examples of such a phase are the early industrialization of Great Britain in the late 18th century or the beginning of the colonial incorporation of Latin America, Africa or Asia.
- Stage 3 (Industrial). Through a process of economic growth and diffusion, other growth centers emerge. The main reasons for deconcentration are increasing input costs (mainly labor and land) in the core area. This diffusion is linked with increased interactions between elements of the urban system and the construction of transport infrastructures.
- Stage 4 (Post-industrial). The urban system becomes fully integrated and spatial inequalities are reduced significantly. The distribution of economic activities creates a specialization and a division of labor linked with intense flows along high capacity transport corridors. The factors that have favored spatial inequalities in the previous phases of development have structured dominant poles of the urban system and favored the setting of a large commercial gateway, usually a world city.