Urbanization Models

Comparative Models of North American Cities

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

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

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

Concentric Zone Model

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

Bid-Rent Curve

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

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

Sector Land Use Model

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

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

Multiple-Nuclei Land Use Model

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

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

Apply the Models

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

Urban Realms Urban Land Model

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”

Borchert Model of Urban Evolution

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

European Cities

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

Latin American Cities

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 City Structure Model

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