Urban Realms Model
Each realm is a separate economic, social and political entity that is linked together to form a larger metro framework.

Main issue to note with this model is that the city has been decentralized and that edge cities are now the center of realms which surround the city. The main CBD is no longer as influential as it once was. Know what an edge city is to fully understand this model.

The creator of the theory of urban realms was James E. Vance Jr., and he created it in the 1960’s.

Now urban realms have become, so large they even have exurbs, not just suburbs.
Exurbs are suburbs that are, so far away from a city they really can’t be called suburbs any more.

The model works extremely well wit the San Francisco Bay area, because it is where Vance came up with the model for it.

The city this worst applies to is to Phoenix, Arizona, because the city just sprawls, with very bad development, and shows a lot of characteristics of urban sprawl.

3. Urban Realms Model

a. Vance developed the urban realms model from his observation of the San Francisco Bay area and its sprawling metropolis.
b. This model includes independent suburban downtowns as their foci, and yet they are within the sphere of influence of the central city and its metropolitan CBD.
c. Each urban realm depends on four factors:
i. The overall size of the metropolitan region
ii. The amount of economic activity in each urban realm
iii. The topography and major land features, which help to identify each realm
iv. The internal accessibility of each realm for daily economic functions and travel patterns.
d. An urban realm is likely to become self-sufficient if:
i. The size of the overall metropolis is large
ii. There is a large amount of decentralized economic activity in the region
iii. Topography barriers isolate the suburban region
iv. Good internal accessibility for daily commercial and business travel exists (especially to airport)