Final answer:
The emergence of self-sufficient suburban sectors with independent downtowns is linked to the rise of New Urbanism, the development of Edge Cities, and the adaptation to city growth exemplified by the Multiple Nuclei Model, all of which have fostered decentralization of urban cores.
Step-by-step explanation:
Suburban Development and Urban Planning
The emergence of large self-sufficient suburban sectors, each focused on a downtown independent of the central city, can be explained through concepts like New Urbanism, Edge Cities, and the Multiple Nuclei Model. In the context of New Urbanism, since the 1980s there has been a push to create mixed-use developments that provide a combination of residential, business, and recreational facilities, often centered around public transportation, effectively reducing the dependency on central urban areas. This has led to the development of vibrant suburban areas with their own economic and social centers.
Edge Cities emerged primarily in the 1970s as suburbs that attracted businesses due to more affordable land and efficient highways. These edge cities boasted a significant number of businesses and became alternate commercial hubs competing with traditional downtown areas. However, they typically had very few residents, inverting the concept of the bedroom community.
The increase in suburban living was influenced by the advent of the automobile and the expansion of the highway system, which allowed for greater mobility. The Multiple Nuclei Model further outlines how cities have evolved to include multiple smaller business districts that serve the needs of these newly formed suburbs, providing localized services and employment that reduce the need to travel to the central city.