Urbanization Models

1. Urbanization Models

2. The Central Business District • Definition: • CBD- original core of a city’s economy, like a nucleus of a cell • CBD is compact, less than 1% of urban land area • But contains a large % of shops, offices, and public institutions • Consumer services and business services are attracted to the CBD because of its accessibility • Center is easiest part of city to reach from the rest of the region • Focal point of region’s transportation network • Characteristics of a CBD • High land costs • Discourages Industry in the CBD • Intensive land use • Skyscrapers • All of the following models possess a central business district • Degree of influence and geographic location of CBD varies throughout different models Comparative Models of North American Cities

3. Concentric Zone Model • Also called the Burgess model • Developed in 1920’s by E.W. Burgess • 1st model to explain and predict urban growth • All other urban models are built on this model • Based on urban growth in Chicago • Model suggests that a city’s land use can be viewed from above as a series of concentric rings • As the city grows and expands, new rings are added and older rings change their function • Size and shape of rings vary per city Comparative Models of North American Cities

4. The five rings: • 1- CBD • innermost ring where non-residential activities are located • 2- Zone of transition • Contains industry and poorer-quality housing • Immigrants to city often 1st live here • 3- Zone of working-class homes • Modest, older homes occupied by stable, working-class families • 4- Zone of better residences • Contains newer and more spacious houses for middle-class families • 5- Commuter Zones • Beyond the continuous built-up area of the city Comparative Models of North American Cities

5. The model assumes a process sometimes called invasion and succession (or succession migration) • Definition: • New arrivals to cities 1st tend to move to the inner rings near the CBD • This pushes the people and economic activities already present out into further rings • This constant pattern can lead to a ring known as the zone in transition • Definition: • Zone outside CBD • Never really developed • Developers know that it will be constantly caught in shift • Sometimes called “skid-row” • In model, the CBD is the premiere land-use ring nearest the point of maximum accessibility • Called peak land value intersection • Highest real estate prices • Land values decrease as you move away from CBD • Furthest ring the cheapest Concentric Zone Model

6. Bid-Rent curve predicts the land prices and population density decline as distance from the CBD increases • Bid-rent curves show the variations in rent different users pay for land at different distances from some peak point of accessibility and visibility in the market • Usually the CBD • Transportation costs increase as you move away from the market • Rents usually decrease as distance increases from the market Bid-Rent Curve

7. Different types of land use generate different bid-rent curve • Ex: commercial retail, industrial, agriculture, housing • Bid-rent curves explain the series of concentric rings of land use found in the concentric zone model • Model shows a pattern in which architectural form and function of buildings match in each concentric ring and urban land use Bid-Rent Curve

8. Sector Model was developed by Homer Hoyt in 1939 • Discovered a twist on the concentric zone pattern • According to Hoyt, the city develops in a series of sectors, not rings • Also based off of Chicago • Model grew out of observations that there were urban land-use zones of growth based on transportation routes and linear features • roads, canals, railroads, major boulevards • Not just concentric zones around the CBD Sector Land Use Model

9. The Sector Model explained that similar land uses and socioeconomic groups clumped together in geometric sectors • Certain areas of the city are more attractive for various activities • Sectors radiated out from CBD along particular transportation routes • Ex: • Many factories follow rail lines, housing followed public transportation, visitor services along major highways Sector Land Use Model

10. New Model of urban growth discovered in 1945 • Chauncy Harris and Edward Ullman • Unlike previous models that focused on a strong CBD, this model suggested that growth occurred independently around several major focal points • A.K.A. a city is a complex structure that includes more than one center around which activities revolve • Ex: airports, universities, highway interchanges, ports • Focal points may be distant from “original” CBD and only loosely connected • Suggesting a reduced dominance of the CBD Multiple-Nuclei Land Use Model

11. The multiple nuclei model reorganized that land use zones often popped up at one, in chunks • Industrial parks, shopping centers, and housing zones could be built in one, giant sweep of construction and be only very loosely connected to the original heart of the city • The model does not suggest the CBD is not necessarily unimportant • but does show that new areas of intense, urban growth (called nuclei) can grow simultaneously around key nodes of access or industry • Some activities are attracted to particular nodes, whereas other try to avoid them • Example: • A university node might attract pizza places and bookstores Multiple-Nuclei Land Use Model

12. The three models help to understand where people with different social characteristics tend to live within an urban area • Can also help explain why certain types of people live in particular places • Uses social area analysis • Uses census information to compare characteristics • None of the models individually explain why different types of people live in distinctive parts of the city • When combined, more helpful • Critics • Models are too simple • Fail to consider the variety of reasons that lead people to select particular residential locations • All three models created between WWI/ WWII • No longer relevant • The models say that most people prefer to live near others who have similar characteristics • Concentric Zone • Consider two families with the same income and ethnic background • One family owns a home, the other rents • The owner would more likely live in an outer ring and the renter in the inner ring • Sector Model • Given two families who own homes, the family with the higher income will not live in the same sector of the city as the family with the lower income • Multiple Nuclei • People with the same ethnic or racial background are likely to live near each other Apply the Models

13. Developed by James Vance in 1960s • Influenced by increasing importance of automobile • Explained suburban regions that were functionally tied to mixed-use, suburban downtowns with relative independence from the CBD • Developed while observing the San Francisco Bay area metropolis • Model grew from the multiple-nuclei model • Argued nuclei were not just focal points of urban growth but developing into functioning “urban realms” • Urban realms model recognized that many people’s daily lives and activities occurred within a fixed activity space within a portion , or urban realm, of a larger metro region • In these “urban realms” on could find suburban downtowns filled with amenities needed for living • “urban realms” Urban Realms Urban Land Model

14. In the 1960’s, Samuel Borchert studied cities in the United States and linked historical changes to urban evolution • Borchert’s model defined four classical of cities based on the transportation technology that dominated the era when the city hit its initial growth spurt and found it’s comparative advantage • Classifications • Stage 1 • Hit growth spurt in “sail-wagon” era of 1730-1830 • Mostly near ports and waterways for transportation • Stage 2 • “iron-horse” cities • Grew around rivers and canals between 1830-1870 when railroads and steamboats were growing rapidly • Stage 3 • “steel-rail epoch” • 1870-1920 • During IR, when steel industry blossomed • Stage 4 • 1920 • Linked to air and car travel Borchert Model of Urban Evolution

15. In contrast to U.S. cities, wealthy Europeans still live in inner rings of the upper-class sector • Not just in the suburbs • As in the U.S. wealthier Europeans cluster along a sector extending out from the CBD • Often away from factories, on higher elevations • Before electricity social segregation was vertical • Meaning poor people lived in the basements or attics of buildings • Today lower income families live outside the inner-city • Mainly outskirts European Cities

16. Latin American City Structure Model • Also called Ford-Griffin Model • Created by Larry Ford and Ernest Griffin • Particularly focused on areas colonized by Spain • Most medieval cities in Europe were laid out in unplanned jumbles • 1400s- Renaissance saw rebirth of Greco-Roman architecture and planned cities • 1573- Spain passed a law ordering all colonial cities be built according to Greco-Roman designs • Prominent, rectangular plazas dominated by Catholic Church and major governmental buildings Latin American Cities

17. Commercial and residential zones encircled the Latin American plaza • Similar to CBD in North American cities • CBD was most important in the focus of Latin America • Suburbanization weaker • In a Latin American city, wealth typically decreases as one moves outward from the downtown area • Typically squatter settlements and rings of poverty are found in rings outside of the CBD • Zones of squatter settlements are called Perifericos • Other zones • Zone of in situ accretion • A region transitioning towards maturity and development that is a mix of middle-income and lower-income families • Zone of maturity • Includes services and infrastructural development Latin American City Structure Model