In 1925, Burgess presented a descriptive urban land use model, which divided cities in a set of concentric circles expanding from the downtown to the suburbs. This representation was built from Burgess’ observations of a number of American cities, notably Chicago, for which he provided empirical evidence. The model assumes a relationship between the socio-economic status (mainly income) of households and the distance from the Central Business District (CBD). The further from the CBD, the better the quality of housing, but the longer the commuting time. Thus, accessing better housing is done at the expense of longer commuting times (and costs). According to this monocentric model (see above figure), a large city is divided in six concentric zones:
- Zone I: Central Business District (called the “loop” in Chicago) where most of the tertiary employment is located and where the urban transport infrastructure is converging, making this zone the most accessible.
- Zone II: Immediately adjacent to the CBD a zone where many industrial activities locate to take advantage of nearby labor and markets. Further, most transport terminals, namely port sites and railyards, are located adjacent to the central area.
- Zone III: This zone is gradually been reconverted to other uses by expanding manufacturing / industrial activities. It contains the poorest segment of the urban population, notably first generation immigrants living, in the lowest housing conditions.
- Zone IV: Residential zone dominated by the working class and those who were able to move away from the previous zone (often second generation immigrants). This zone has the advantage of being located near the major zones of employment (I and II) and thus represents a low cost location for the working class.
- Zone V: Represents higher quality housing linked with longer commuting costs.
- Zone VI: Mainly high class and expensive housing in a rural, suburbanized, setting. The commuting costs are the highest. Prior to mass diffusion of the automobile (1930s), most of these settlements were located next to rail stations.
According to Burgess, urban growth is a process of expansion and reconversion of land uses, with a tendency of each inner zone to expand in the outer zone. On the above figure, zone II (Factory zone) is expanding towards zone IV (Working class zone), creating a transition zone with reconversion of land use. Although the Burgess model is simple and elegant, it has drawn numerous criticisms:
- The model is too simple and limited in historical and cultural urban context that prevailed up to the 1950s. It is a product of its time.
- The model was developed when American cities were growing very fast in demographic terms and when motorized transportation was still uncommon as most people used public transit. Expansion thus involved reconversion of existing land uses. This concept cannot be applied in a contemporary (from the second half to the 20th century) context where highways have enabled urban development to escape the reconversion process and to take place directly in the suburbs.
- The model was developed for American cities and has limited applicability elsewhere. It has been demonstrated that pre-industrial cities, notably in Europe, did not at all followed the concentric circles model. For instance, in most pre-industrial European cities, the center was much more important than the periphery, notably in terms of social status. The Burgess concentric model is consequently partially inverted.
- There were a lot of spatial differences in terms of ethnic, social and occupational status, while there were low occurrence of the functional differences in land use patterns. The concentric model assumed a spatial separation of place of work and place of residence, which was not generalized until the twentieth century.
However, the Burgess model remains useful as a concept explaining concentric urban development, as a way to introduce the complexity of urban land use and to explain urban growth in American cities in the early-mid 20th century.