Urban Models & Theories: How are Cities Organized & How do they Function?

A. Urban Morphology The layout of a city, its physical form & structure Berlin, Germany With wall (above) And without wall (right)

B. Functional Zonation Division of city into regions (zones) for certain purposes (functions) Cairo, Egypt Central city (above) Housing projects (right)

C. The Changing City & John Borchert 4 epochs in evolution of Amer. metropolis based on impact of transportation & communication: Sail-Wagon Epoch (1790-1830) – associated w/ low technology Iron Horse Epoch (1830-1870) – steam-powered locomotive & spreading rails Steel-Rail Epoch (1870-1920) – full impact of Ind. Rev. (steel), hinterlands expand

C. The Changing City & John Borchert Auto-Air-Amenity Epoch (1920-1970) – gas-powered internal combustion engine High Technology Epoch? (1970-?) – service & information industries (NOT part of Borchert’s model)

D. Modeling the North American City All cities have the following: Central business district (CBD) Central City (CBD + older housing zones) Suburb (outlying, functionally uniform zone outside of central city)

E. Concentric Zone Model Created by Ernest Burgess (1920s Chicago) Divides city into 5 concentric zones, defined by function Newest settlers use older housing near city center (migrants to industrial jobs) Previous groups move outward to higher-income areas as they assimilate Concentric pattern arises as land uses compete and are sorted according to ability to pay for land As one moves toward central city, land becomes scarcer but accessibility improves, rent therefore increases, and land uses that cannot exact sufficient rent are sorted out Similar activities likely to be found at similar distances from central business district (CBD)

5 Rings of Model 1) CBD – at center of model 2) Zone of transition (residential deterioration & light industry) 3) Zone of independent worker’s homes (blue-collar workers) 4) Zone of better residences (Middle-class) 5) Commuters Zone (Suburbs)

F. Sector Model Created by Homer Hoyt (1939); criticized Burgess Model as too simple & inaccurate Focuses on residential patterns Assumes land use is conditioned by transportation routes radiating outward from city center High-income areas along fashionable boulevards, waterfronts, or high ground Industry along river or rails Low-income near industry Middle-income btwn. low and high sectors

City grows outward from center, so a low-rent area could extend from CBD to city’s outer edge Same is true w/ high-rent, transportation, and industry

G. Multiple Nuclei Model Created by Harris & Ullman (1945) Seen in post WWII – early suburbanization Downtown CBD not only core of business land use Other nuclei develop - special retail districts, office parks, light manufacturing in city Metro areas develop “suburban downtowns” (called “edge cities”)

Transportation and Urban Growth DISCUSSION: * Do you recognize aspects of the layout of your town or city that are remnants of past transportation eras? *

H. Edge Cities Suburban nodes: high-rise offices, shopping, entertainment, hotels - designed for auto travel Located along freeways/beltways 3 distinct varieties of edge city phenomenon: Boomburgs: the most common type, having developed incrementally around a shopping mall or highway interchange Greenfields: having been master-planned as new towns, generally on suburban fringe Uptowns: historic activity centers built over older city or town (sometimes a satellite city) Ex: Tyson’s Corner

Tyson’s Corner

Tysons Corner is poised to become North America's only example of a former sprawling edge city becoming a fully-fledged downtown in its own right

I. Galactic City or Peripheral Model (AKA Edge City Model)

Philadelphia's Edge Cities DISCUSSION: * What are the elements required for a suburban area to be categorized as an "edge city"? *