Urban Structure Study Notes (PDF)

Central City: An urban settlement that has been legally incorporated into an independent, self-governing unit.
- Most central cities in the United States have experienced a population decline since the 1950s.
- The decline is primarily attributed to the growth of the suburbs.

Central Business District (CBD): The area commonly referred to as the "downtown" of a city.
- Characteristics of the CBD:
- It is the best-known and most visually distinctive part of the city.
- Typically, it is the oldest part of the urban area.
- Hosts a concentration of public, business, and consumer services due to its accessibility.
- It serves as the easiest part of the city to reach from various regions, acting as the focal point of the transportation system.
- Example: CBD in Saint Louis, MO is depicted.

Suburbs: Built-up areas surrounding the central city.
- Historical Population Distribution (1950 vs. 2000):
- 1950:
  - 20% of Americans lived in suburbs.
  - 40% lived in cities.
  - 40% lived in small towns and rural areas.
- 2000:
  - 50% of Americans lived in suburbs.
  - 30% lived in cities.
  - 20% lived in small towns and rural areas.
- Example: Aerial photograph from the 1950s showing a subdivision in Ferguson, MO, just outside St. Louis.

Suburban Sprawl: The uncontrolled horizontal expansion of developed areas.
- Environmental Costs of Sprawl:
- Infrastructure: Roads and utilities must be extended to connect isolated new developments, leading to increased costs and resource allocation.
- Transportation: Motorists are required to drive longer distances to access basic services, resulting in higher fuel consumption and contributions to traffic congestion.
- Land Use: Agricultural land is often lost to residential developments, impacting food production and local ecosystems.

The combined entity of the central city and its surrounding suburbs is referred to as an urban area.

Source: Adapted from Contemporary Human Geography, 3rd edition by James Rubenstein.