Common section

Chapter 17

CBD to Suburbia: Urban Geography

In This Chapter

bulletUncovering urban origins

bulletSeeing how they grow

bulletInvestigating internal differences

bulletPondering dust domes and other problems

I f the year was 1790, then this could be a newspaper headline: 195,000 Americans Now Live in Cities!

Sounds preposterous, doesn’t it? But in fact, in 1790, the first U.S. Census revealed that only 5 percent of the nation’s 3.9 million inhabitants lived in cities, which actually were tiny islands in a sea of rural settlement and wilderness. In every census since, the urban percentage has marched steadily upward (as seen in Figure 17-1). In 1920, it exceeded the rural percentage for the time, and has never looked back. Today around 75 percent of Americans may be categorized as urban. That amounts to about 222 million people out of a total population of some 285 million.

Studying the Urban Scene

As centers of population, political and religious power, trade, and commerce, cities have always been geographically significant. At no time, however, have they been more important than they are today — not only because so many people live in them, but also because cities have grown in number and size. Literally millions of square miles of natural landscapes have become “cityscapes.” Indeed, cities have become so expansive that they have complex geographies of their own. No wonder an entire sub-field called urban geography, the subject of this chapter, has developed to analyze:

bulletThe reasons why cities develop at particular locations

bulletThe factors that underlie urban growth

bulletThe spatial arrangement of commercial, industrial, residential, and other kinds of land use within cities

bulletThe planning that is meant to improve the quality of urban life

bulletThe social and political tensions between people who live in different parts of cities, and between cities and fringing political jurisdictions

bulletThe environmental quality issues occasioned by urban development and growth

Each of these will be touched upon to some extent in the pages that follow.

What does “urban” mean?

Obviously, urban means a lot of people bunched together in a recognizable town or city. But how many? The answer varies from one country to the next. As far as the folks who run the U.S. Census are concerned, the threshold figure is 2,000. Thus, if you have a town with that many people, then its residents are considered urban. If a neighboring town numbers 1,999 souls or less, then they are classified rural. Depending on where you live, “urban = 2,000 people” may make a lot of sense or sound like a bad joke. Throughout the lightly populated Dakotas, for example, the definition seems entirely appropriate. In New York City, however, where you may have that many people and more in a single building, the number 2,000 may seem woefully lacking.

Getting a Global Perspective

At the global scale, urbanization has broadly mimicked the American experience. No worldwide census data are available from back in 1790, but available anecdotal and statistical evidence suggests that the urban percentage for the world as a whole was about that of America’s. Today, some 46 percent of the world’s people live in urban areas, but that number masks significant variation. In the more developed world, 75 percent of the populace (exactly the American percentage) live in cities, although in some countries, the figure is much higher. Urbanization in Uruguay and Argentina, for example, is currently at about 92 percent and 90 percent respectively.

On the other hand, in the less-developed countries the rate of urbanization today is about 40 percent. It makes sense that this figure is so much lower because by definition a less-developed country is one whose economy is based on agriculture — so the populace tends to be down on the farm instead of downtown. But that statistic also masks variation. In Mongolia, for example, 57 percent of the people are urbanized, while in Bangladesh, the figure is 21 percent. Nevertheless, some of the world’s largest cities have sprung up in developing countries, and with them some of the most challenging venues regarding urban planning and quality of life issues. Table 17-1 shows the top 20 largest areas. (Note: City is defined in Table 17-1 as a contiguous metropolitan area. That may include any number of municipalities that fringe a central urban area.)

Table 17-1

Economic development brings with it employment prospects that are largely urban-based (for more information on this, see Chapter 15). Now, in developed countries these opportunities tend to be widespread and manifested by country-wide urbanization. In developing countries, however, they tend to be much more concentrated in the geographic sense with the result that the populations of one or two cities (the principal development centers) skyrocket. That is the reason why, as Table 17-1 shows, more than half of the world’s twenty largest cities are in developing countries

Because of concentrated urban growth, an important aspect of Third World urbanization is the disproportionate occurrence of primate cities. No, this has nothing to do with Planet of the Apes. A city is classified as primate when it is far and away the largest city of a country. Classically, it tends to be at least twice as large as the second largest city. More often than not, it is also the capital. Thus, it stands as the overwhelming center of population, political power, employment, commerce and wealth.

Primate cities are powerful magnets for rural-to-urban migration, often resulting in sprawling, disease-ridden slums inhabited by poor folk who have come to seek work. Also, the concentration of so much power and prospective opportunity in a single setting may result in domestic political tension that pits inhabitants of a primate city against people in other parts of the country that feel deprived of their fair share of economic opportunity. On balance, therefore, the consequences of having a primate city are not entirely positive.

As suggested by the 1790 census data at the start of this chapter, the modern reality of so many people worldwide living in so many cities is at odds with the way things used to be. In fact, urbanization is at least a 5,500 year-old process whose early geography may be traced to a handful of locales.

Getting Started: Urban Hearths


Cities originated independently in five regions (shown in Figure 17-2) often called urban hearth areas — places where the first cities developed. They include:

bulletMesopotamia: The Tigris-Euphrates River valley that mainly lies in modern-day Iraq.

bulletNile Valley: Especially in what is now Egypt.

bulletIndus River Valley: In what is now Pakistan.

bulletThe Lower Huang Ho (Yellow River) Region: This is located in Northeastern China.

bulletMesoamerica: The region that extends northward from Nicaragua to and including Central Mexico.

Mesopotamia probably has the honor of being the first. Its oldest urban ruins date back about 5,500 years. Ancient Egypt appears to be a close second.

Trade and commerce played important roles in the growth and development of hearth-area cities. But so, too, did the need for centers for religious rituals and observances. As a result, imposing structures of ceremonial significance (such as pyramids and temples) dominated “skylines.” These tended to be located alongside or at the intersection of broad boulevards aligned in directions that often had theological significance. Complementing these imposing structures were achievements of more mundane, yet fundamental, varieties. Yesterday’s cities (yes, even without traffic lights and fast-food restaurants, they’re still considered cities), with populations that probably didn’t exceed 25,000, showcased distinct residential, commercial, and institutional zones, as well as municipal services such as water supply and garbage removal. These prove that municipal planning and governments were at work even back then. Thus, the urban hearth areas were scenes of important experiments and innovations in human settlement, the results of which were passed down to succeeding generations, modified, and ultimately spread to other lands.


Geographically, what is perhaps most important about these hearths is their locations. Each coincided with an area of high agricultural productivity. This positioning made a great deal of sense because the principal prerequisite for the appearance and growth of cities is an agricultural surplus. Why? Because that alone frees some people of the necessity to produce food and allows them to become artisans, traders, shopkeepers, soldiers, clerics, and so on, and cluster in settlements — cities — that promote the interaction of those services. Accordingly, each hearth (except Meso-America) is located amidst fruitful lands that roughly parallel one or more large rivers. The richness of the soils, whose fertility was regenerated by silts deposited by periodic floods, allowed people with even the most basic agricultural technology to produce good harvests (food surpluses) on a regular basis. Each hearth (including Meso-America) was also noted for impressive irrigation systems that maximized the agricultural potential of local waters and soils. Given the significance of these water systems, whether natural or human in origin, the early cities and their peoples are sometimes referred to as hydraulic civilizations.

Finding Sites for Cities


While the civilizations that produced those early cities are things of the past, the locations of urban hearth areas demonstrate a geographic principle that has persisted through time. Namely, cities don’t just happen. Instead they tend to spring up in particular locations because of some characteristic(s) of place that was attractive to settlers.

For example, and strange as it may seem today, the Spaniards settled the Los Angeles, California area for its agricultural potential. Mountains and foothills come down to the sea along the West Coast, affording limited venues for agriculture and settlement. Los Angeles area, however, offered a substantial expanse of relatively flat land complemented by a then-adequate local water supply that trickled down from the fringing San Gabriel Mountains. That was then. Today, few, if any, people live in LA because of its crops potential (legal ones, that is), and that makes an important point about urban location factors. Namely, the reason why a city began at a particular location may have nothing to do with the reasons why people live there today.

The list of factors that explain why cities began and developed at particular sites is lengthy. The four that are discussed in the following sections are the most popular.


A confluence is a place where two rivers meet to form a combined flow. Pittsburgh, Pennsylvania, for example, began as a small settlement where the Allegheny and Monongahela Rivers join to form the Ohio River. Other examples are St. Louis, Missouri, near the point where the Missouri and Mississippi join waters; Khartoum, Sudan, where the White Nile and Blue Nile come together; and Manaus, Brazil, where the Amazon and Rio Negro combine their waters.

Rivers served as highways in olden times, so being at a confluence was like being at the hub of a transportation network. Confluences are prone to flooding, however, so availability of high ground is essential for safe settlement. Fortunately, plenty of high ground is available in Pittsburgh. In contrast, the land is rather low-lying where the Mississippi and Missouri meet. For that reason, St. Louis is not located right at that confluence, but a few miles downriver, where the banks are appreciably higher.

Protected harbor

Ever try to load or unload a sailing ship that is pitching to and fro in moderate-to-heavy waves? I didn’t think so, and don’t bother trying. It’s very difficult and downright dangerous. What you need are calm waters, preferably in a protected harbor setting, where intervening land negates the big waves of the open sea. Because shipping has long been a principal means of moving people and goods, protected harbor settings have long been prime sites for settlement. Geographically, what do Boston, New York, Baltimore, Norfolk, San Diego, San Francisco, Seattle, Vancouver, Tokyo, Sydney, Mumbai (Bombay), Karachi, Hamburg, Havana, and Rio de Janeiro have in common? You got it.

Head of navigation

A head of navigation is the farthest point upriver that a boat or ship can travel from a river’s mouth. Washington, DC, for example, is located at the head of navigation of the Potomac River. That is, ships of good size can proceed up the Potomac from its mouth as far as the site of that city, where rapids make further navigation impossible. In other instances, waterfalls, shallow water, or narrowness calls a halt to water-borne traffic. In the settlement of North America, heads of navigation sometimes proved a logical spot for boats to stop, be unloaded, and later for settlements to develop. In some cases, these sites afforded other advantages for settlement. Where waterfalls or rapids impeded navigation, these features sometimes provided sources of waterpower for mills and other economic activities. Narrows or shallow water, in contrast, sometimes offered opportunity for bridge construction. Other examples of heads of navigation in the United States include Trenton, NJ (Delaware River); Louisville, KY (Ohio River); and St. Paul, MN (Mississippi River).

Defensive sites

Defensive considerations were paramount in the siting of several cities. The oldest part of Paris, for example, is the Ile de la Cite, a small island in the middle of the Seine River. The river served as a protective moat for the island’s oldest known inhabitants, a tribe called the Parisii. Similarly, the oldest part of Montreal is an island in the St. Lawrence River that served a defensive purpose.

Some rivers exhibit dramatic U-shaped bends called meander loops. By siting a town on the inside of a loop, the river served as a protective perimeter. Examples of this include New Orleans, Louisiana, and Berne, Switzerland.

Acropolis sites, characterized by locally high ground, which is fairly easy to defend, have also been favored. Examples include Quebec City, Albany (New York), and Athens, Greece — whose famous Acropolis is the source of this category. Peninsula sites were also favored because a wall across a neck of land, complemented by the surrounding water (a natural moat), greatly facilitated defense. Boston and Bombay, also noted for their natural harbors, are good examples.

Because of these and other site-related factors, settlements developed at various locations around the world. All were small at first. Many did not stay that way.

Getting Big: Urban Growth

At favored sites around the world, hundreds (if not thousands) of once-humble settlements have developed into cities of varying size. And the process continues. In fact, urbanization is not just a major human characteristic, but also a major trend. But the pace of urban growth and the reasons for it are not the same everywhere. Because space does not permit a truly global treatment of this truly global process, I’m going to focus on a prime example of the urbanization process — the United States.

Much of the growth of American cities has been due to immigration and natural population growth. But other factors have also encouraged cities to expand not just population-wise, but also with respect to the physical area taken up by them. The following sections discuss some of the principal factors.

Rural-to-urban migration


Over the world as a whole, the last century has witnessed substantial rural-to-urban migration. In the United States and several other countries, a couple of processes have been fundamental to this shift.

Mechanization of agriculture and farm consolidation

Agriculture was once a largely manual enterprise that required many hands to tend a farm of decent size. But with the advent of farm machinery (tractors in particular), the number of people needed to do farm work was greatly reduced. At the same time, mechanization also encouraged farm consolidation (in which one farmer buys out another, thereby increasing the acreage owned by the buyer) because tractors made it possible for a farmer to farm much more land than was the case before. Thus, the pre-mechanization rural landscape that consisted of a large number of small farms was transformed into one containing a comparatively small number of large farms. In 1920, (largely pre-tractor times) 6.5 million farms in the U.S. averaged 149 acres. Now about 2.1 million farms average about 430 acres. During the same period, farm population dropped from 31 million to 4 million. Cities absorbed the brunt of the difference.

Changing economy

The mechanization of agriculture was symptomatic of a structural change in the overall economy that witnessed an increase in industrial and commercial enterprises that were largely urban-based. Manufacturing was particularly important because it afforded job opportunities for unskilled or semi-skilled individuals who were either recent immigrants or recently forced off the farm. Thus, in 1870 the overwhelming majority of African-Americans were rural Southerners. Less than a century later, a majority were urban dwellers, many of them holding factory jobs in cities outside of the former Confederacy.

Changing means of transportation


How big would a city be if every inhabitant had to walk to work? The answer is pretty simple: Not very big at all. And in fact, that’s the way things were long ago. When overland transport was exclusively a matter of walking, horseback, carriage, and cart, it took a while to move people and products meaningful distances. As a result, cities tended to be rather compact.

Over the years, however, changes in transportation have allowed people to live progressively farther from their places of employment, thereby expanding the physical size of cities. Following are various “urban transportation ages,” though not all apply to every city.


Prior to about 1890, foot, carriage, or horse-drawn trolley accomplished most movement of people and goods. This resulted in compact cities, the largest of which could be completely traversed in a 30 to 45 minute walk. Attached or closely-spaced housing was the norm.

Electric trolleys

Around 1890, introduction of electric-powered trolley cars provided a quantum leap forward in speed. While a 30-minute walk might allow a commuter to live perhaps as far as 2 miles from work, a commensurate trolley ride could extend the range of residential potential to 5 miles and more. As a result, the outer edge of urban areas expanded significantly.

Commuter railways

Starting around 1900, commuter railways developed using standard, instead of narrow, gauges. The result was another quantum leap in speed that expanded the range of commuting to 20 miles and more. Commuter trains can only travel where tracks are present, of course. Thus, cities expanded along rail corridors that were rather like tentacles, leaving countryside in between.


Advent of mass automobile ownership facilitated unprecedented freedom of choice with respect to residential location. Suburbs consequently developed and “filled in” substantial portions of rural land between the commuter rail tentacles described previously. Until roughly the mid-1950s, however, highways were largely of the 2- and 4-lane variety. Combined with red lights, stop signs, and traffic, commuting speed was somewhat limited and so too, therefore, the distance at which one may choose to live from the city.


Multi-lane, high-speed, limited access (as in limited points of entrance and exit), divided highways first appeared in the early 1950s and, in the U.S., proliferated with the advent of the federally funded Interstate Highway System. Initially, at least, the effect of these arteries was to greatly increase the average speed at which a motorist could travel and therefore also increase the potential distance from residence to job. Complemented by construction of beltways — interstate-style ring roads designed to help people travel around the central city without going through it — this ongoing age has witnessed significant increase in the “filling in” of remaining rural land between commuter rail “tentacles,” and pushed the outer edge of the city in multiple directions, as shown in Figure 17-3.

Automobile ownership

By themselves, neither freeways nor roads of other sorts tell the full story of contemporary urban growth in the U.S. More telling is the number of people who own cars and use those roads and freeways to commute to work from a suburban residence. And that number is humongous. More than 130 million automobiles are registered in the United States and another 80 million trucks of various sorts. According to the 2000 U.S. Census, more than 90 percent of households own a motor vehicle, and 18 percent of households own three or more.

Low-cost fuel

The price of automobile fuel in the United States is relatively low. That prompts urban sprawl by encouraging automobile usage and increasing the distance people are willing to commute. Now, some people may recoil at the notion that gas is cheap in the United States. All they need to do, however, is vacation in Europe or almost any other part of the world to find out firsthand just how inexpensive American gas is. The principal reason for the price difference is low taxes on gas consumption in the U.S., which encourage automobile purchases, new home construction, and other consumer activity that contributes to the economy even as it contributes to urban sprawl.

Home mortgage deductibility

The U.S. federal government has long encouraged home ownership by allowing buyers to deduct from their federal income tax the interest paid on home mortgages. The effect is to encourage new home construction and urban sprawl. Canadians, in contrast, do not get the same tax benefit. Their cities also sprawl, but generally not to the extent of those on the U.S. side of the border. Several factors explain that, and mortgage deductibility is one of them.

Looking Inside the City

In addition to sites and sizes, cities around the world vary dramatically in their internal physical appearance. Numerous cities in Europe, North Africa, and Asia, for example, contain an “old town,” characterized by traditional architectural styles, and a citadel, cathedral, or mosque that towers above historic low-rise buildings. In other cities, strict building codes produce an air of distinctness. Thus, while many modern cities are defined by center-city skyscrapers, Paris and Venice, to take just two of many examples, have uniformly low skylines that preserve historic character and visual dominance of leading landmarks.

Internal physical appearances of cities may also vary as a function of wealth or income of residents. Urban neighborhoods of the rich and poor not only look different, but also tend to occupy different locations in the cities of different countries. Thus, in many developed countries, the urban poor tend to live in older housing in the inner city. The wealthy, in contrast, generally tend to live in the suburbs or urban fringe. In many developing countries, however, the pattern tends to be the opposite. That is, the poor tend to concentrate in slums that are located on the urban periphery while the wealthy are located much closer to the urban core. Accordingly, go up into the hills on the outskirts of many American cities and you are likely to see expensive homes that afford a great view. Do the same in most large Latin American cities, and you are likely to see some of the worst slums and shanties imaginable.

Distinct areas of commercial, industrial, residential, and other kinds of land use came into being as cities grew. Their extent and arrangement vary substantially in different cities in different countries. In the United States, the factors promoting urban growth are largely the same throughout the country. To a fairly substantial extent, therefore, American cities exhibit a certain sameness with respect to their structure.

Specifically, at the center there tends to be a discernible “downtown” dominated by relatively tall building and mostly non-residential land use. On its fringe are high-density residential neighborhoods characterized by high-rise apartments and attached multi-family dwellings. As distance from downtown increases, population density generally decreases. Detached housing becomes the norm and lot sizes increase. Mixed here and there amidst suburbia are shopping centers of varying sizes, with occasional full-blown shopping malls on the periphery of larger cities.

If you live in a city, or are familiar with one, how well does that description conform to your experience? The sections that follow consider urban parts and processes in greater detail.

The Central Business District (CBD)


At or near the center of most cities is what students of urban geography call the Central Business District (CBD) and what normal, well-adjusted people call “downtown.” This is the core of the city and in most instances is characterized by:

bulletThe area where the city began

bulletThe focal point of the main transportation arteries

bulletThe tallest buildings

bulletCity hall, court buildings, and government offices

bulletMajor commercial, retail and office buildings

In some respects “downtown” is preferable to “CBD” because the former infers that much more is going on in the area than just business. Still, the concentration of business enterprises is such that commercial land use dominates the CBD and gives rise (quite literally) to its most outstanding characteristic: large and imposing structures, usually including the tallest buildings in town. Com-petitive bidding for real estate is what leads to those structures, and both the bidding and the buildings deserve at least modest description.

Competitive bidding and the rent gradient


Historically, downtown was the place to be as far as commercial enterprises were concerned. That is because it was the focal point of the transportation network and therefore readily accessible to a high percentage of the city’s population, all of whom were potential customers or employees. As a result, demand for downtown business locations quickly exceeded the supply of real estate. When demand exceeds supply, whether you’re talking real estate or rock concert tickets, the price rises. This competitive bidding for downtown real estate drove up land prices in that area relative to other parts of the city. As a general rule, competitive bidding for land generally decreases as distance from the urban center increases. As a result, land values tend to “peak” downtown and then decrease as distance from the CBD increases — sharply at first, and then more gently (as illustrated by Figure 15-10). Geographically, therefore, land values exhibit a gradient that declines from the CBD to the periphery of the city. The trend line is often called the rent gradient, even though land purchases rather than renting per se is the predominant financial transaction.

Tall buildings

The quintessential result of the downtown peak in the rent gradient is tall buildings. And for good reason. Suppose you have just purchased land downtown and borrowed a hefty amount of money from a bank to do it. Now you’ve got a loan to pay off, along with its accruing interest. Also, given the high price you paid, you can bet your last dollar (if you have one) that the annual real estate tax on your property will be through the roof (if you can afford one).

How can you cope with this predicament and make a tidy profit to boot? Create as much floor space as possible on your property and rent it out to businesses that will pay a pretty penny to locate downtown. And the way to create that floor space is to go vertical — that is, build as many stories (thereby creating as much rental space) as you and your bankers deem feasible. In most cities, you find some tall buildings that are not downtown, but the rent gradient usually guarantees that the CBD will have the highest concentration of them, an example of which is shown in Figure 17-4.

Residential areas


Urban residents generally live in one of two areas: multiple housing buildings that fringe the CBD or detached, single-family residences of outer-city areas. The following sections discuss some of the areas that crop up when people choose to live in and around cities.

Rich folks-poor folks, suburbs-inner city

As a general rule (which has numerous exceptions) people of low-to-modest incomes tend to live in inner-city high-density neighborhoods while the more affluent reside in the suburbs. This geographic pattern is not as old as the cities themselves, but instead evolved over time. Specifically, an old high- density residential area usually adjoins a city’s CBD. Most often the buildings date from pre-automobile times, when the need to be close to work encouraged dense settlement. As affluence rose and transportation improved, the middle- and upper-income people (largely white) tended to move to outlying areas, while low-income people (largely minority) moved into the newly vacant residential spaces. As the number of inner-city poor people rose, landlord incentive to spend money to maintain and improve their housing declined. Slums were the virtually inevitable result despite occupying land little more than a stone’s throw from high-value CBD real estate.

Other factors have subsequently served to place suburban real estate beyond the reach of the inner-city less-well-off. These include local (suburban) decision-making not to build public or low-cost housing, and passage of ordinances that mandate large minimum lot sizes or house sizes. Also, lack of efficient (or any) public transportation in suburban areas decreases the likelihood that the poor will move in.

As a result, cities and suburbs generally end up being inhabited by people of different race and social class. These people tend to have different needs, different attitudes toward social services, different views on the role of government, different perspectives on taxation, and different priorities about how tax money should be spent. Political tension between inner city and suburban residents is an almost inevitable side effect. This sometimes results in one political party being “the party of the city” and another being “the party of the suburb.”

Ethnic neighborhoods

An ethnic neighborhood is a residential area in which people of common origin voluntarily live in close proximity to each other. (This is in contrast to a ghetto, in which the choice of residential location is involuntary.) These are common features of American cities (Canadian and European ones, too) inasmuch as they afford foreign immigrants opportunity to

bulletInteract with others who literally and figuratively speak their language

bulletMaintain contact with kinfolk

bulletHave access to stores and eateries that specialize in familiar goods and foodstuffs

bulletWorship in a preferred manner

The vast majority of these neighborhoods are found in high-density inner-city residential areas. That is a reflection of the (normally) limited disposable income of immigrants, proximity to real or potential places of work, and, again, strong desire to be among people with a similar background.

Applied Geography: Lessons from Bhopal?

On December 2, 1984 an explosion at a chemical plant in Bhopal, India produced a cloud of toxic hydrogen cyanide gas that settled over nearby residential areas. Some 5,100 people died, and many thousands more suffered permanent injures to lungs and eyes. Subsequent investigation suggested the tragedy could have been prevented by modest investments to improve operational safety within the plant. On the other hand, and not to make light of those findings or of the company’s culpability, some have suggested the extent of the disaster was due to a lack of zoning.

Zoning is the process in which urban planners (many of whom are trained in geography) allocate particular kinds of land use to particular parts of a city. The desired purpose is to promote smooth functioning and livability. With respect to Bhopal, why, some have asked, was a factory of that sort and a densely populated residential area ever allowed to exist side-by-side? An appropriate degree of geographic separation between plant and people, consistent with rational zoning, would not have prevented the accident, but no doubt would have resulted in far fewer casualties.

Suppose a manufacturer of toxic chemicals wanted to build a plant in the city or town where you live. Also assume that you are the local urban planner (Congratulations!) and that the plant’s coming to town is a done deal because its economic benefits are too good to pass up. The only remaining question is: Where should it be located? What’s your opinion? And how would you respond to critics of zoning who contend that property owners should be allowed to do whatever they please with their real estate (including building a chemical plant on it) without first securing the approval of people like you?


As previously mentioned, a ghetto is an involuntary neighborhood where members of a group are forced to live. Typically, they are found in an inner-city, high-density residential area. Ghetto is Italian for “foundry,” and reflects the fact that Jews in Venice of old were relegated to (and literally locked in at night) a small area in the factory district.

Opinion varies (often heatedly so) about the appropriateness of the term in America, where it has been applied most often to the African-American and Asian-American urban experiences. While these peoples have never been literally locked in a particular area, in certain times and cities, they have been victims of red lining. This is a discriminatory and now illegal practice whereby real estate agents mark off on a map (classically with a red pen) parts of town in which housing may and may not be sold to members of these groups. The result, for all intents and purposes, is a ghetto.

Leaving Downtown, Living Downtown

In recent decades two rather opposing processes have impacted the character of cities. One involves movement to the suburbs and outer fringe of large stores and other entities formerly located downtown. The other (and more recent change) entails the movement of middle- and upper-income people into downtown areas. Each process, described below, has brought significant socioeconomic change — for better or for worse — to affected areas.

Moving out of downtown

Decentralization refers to the appearance in the outer city of functions and land use formerly associated almost exclusively with the CBD. The quintessential example is a large downtown department store that closes, perhaps after years of being part of the CBD, and relocates to a newly opened suburban shopping mall. The most profound effect is to move commerce and retailing from the center city to the outer city (hence decentralization), often resulting in vacant real estate downtown and loss of jobs for inner city residents. Here are some principal manifestations and results.

Suburban shopping malls

Enclosed shopping malls consisting of two or more major department stores and dozens of lesser-sized shops of considerable variety are perhaps the highest expression of decentralization (illustrated by Figure 17-5). They come about for one or more of the following reasons:

bulletThe cost of land or rent is cheaper in the suburbs than downtown.

bulletProximity to people with high disposable income stimulates business, and more people fit that description in the suburbs than in the central city.

bulletMalls are more convenient to get to by auto than is downtown. Specifically, getting to a suburban mall is likely to involve less traffic, fewer lights, and lots of free parking.

bulletShoppers (especially suburbanites) tend to prefer mall shopping because of the juxtaposition of different kinds of shops, their comparative cleanliness and perceived safety, and their enclosed climatically controlled environment.

Office parks

An office park is a cluster of multi-story office buildings (glass facades are particularly popular) that typically occupy more than enough acreage at or near a major suburban intersection. Trees and other landscaping (hence, park) complement the architecture. The suburban location often constitutes a preferable commute for employees who might otherwise have to drive downtown. Similarly — and just like shopping malls — the locations facilitate accessibility by existing near potential middle- and upper-income clients, who are more likely to reside in the outer city than the inner city, and who prefer the former setting to the latter as a place to take their business.

Edge cities

Comparatively small edge cities sometimes appear on the outer fringe (or edge) of large cities. Sometimes this is simply the result of merging together due to urban growth. More often, however, edge cities are newly incorporated areas that arise in response to the needs of suburbanites for a wide range of goods and services, and their preference to obtain them in car-friendly places that are closer to home than the old CBD.

Jurisdictional spillover

Urban sprawl often results in a contiguous urban area that exceeds the original city limits and spills over into the territory of other cities, counties, or even states. As a result, hundreds or even thousands of people may earn a paycheck in one jurisdiction, but pay taxes and spend their disposable income (thereby encouraging job-creation) in another jurisdiction. This is cool as long as it all “evens out,” but it seldom does. The jurisdiction that “loses” is the one with the highest number of workers who live somewhere else, and typically that is the central city.

Moving back downtown

In recent years, a rather provocative geographic trend has been occurring that rather flies in the face of urban sprawl and decentralization. Called gentrification, it’s the process by which middle- and upper-income people (who you would normally expect to see settling down in the ’burbs) buy and refurbish central-city housing.


The causes of this are diverse, but typically include one or more of the following:

bulletPreference for social diversity and cultural amenities, which typically are in greater supply in the CBD as opposed to suburban settings.

bulletDesire by people whose jobs are downtown to forgo the time and cost of commuting from the urban fringe.

bulletThe often favorable cost differential between buying and refurbishing inner city property versus the purchase of property with a home on it in the suburbs.

bulletAvailability of large rental spaces downtown pursuant to commercial and manufacturing concerns that have decentralized or gone out of business.


Having been set in motion, gentrification may be manifested in ways that may include the following:

bulletSocial change takes place in the inner city gentrifying area as more affluent people move in.

bulletHousing stock becomes refurbished.

bulletThe continued influx of buying power leads to competitive bidding, which drives up housing and residential rent costs.

bulletSpending by newcomers has a spillover effect, increasing the value of commercial real estate as landlords find they can command higher rents.


Once it has firmly taken hold, gentrification may have significant consequences that include the following:

bulletRising rents cause displacement of long-term commercial and residential tenants, giving rise to homelessness.

bulletLow-rise buildings are bought and demolished to make way for high-rises.

bullet“Mom and pop” stores become boutiques. The former unique commercial character of the area becomes increasingly “placeless” as chain stores and franchises become more a part of the local landscape.

bulletThe urban tax base expands.

The bottom line is that gentrification is a double-edged sword. It encourages homelessness and social displacement even as it encourages revitalization of the inner city and reinvention of the old CBD.

Facing up to Environmental Issues

Just as city growth has had diverse social and economic consequences, so, too, has it given rise to a host of environmental challenges. The following sections cover a few of the biggies.

The urban heat island

The atmosphere over a city tends to be significantly warmer than over rural areas, a phenomenon called the urban heat island. While the effect may be a modest blessing during the cold of winter, it can also amplify summer heat waves, resulting in higher rates of health emergencies and heat-related fatalities than in non-urban areas. Here are three reasons for this phenomenon:

bulletAsphalt, concrete and other hard materials that dominate city surfaces have rather high capacities to absorb solar energy, causing urban areas to warm up much faster than countryside.

bulletHeat is a by-product of motors and machines, which abound in cities. Ironically, air conditioners are a major contributor to urban heat islands during summer.

bulletExhaust from automobiles and engines is warm in and of itself, but also has high concentrations of gases that absorb and retain solar energy with great efficiency.

Dust domes and smog

Exhaust from internal combustion engines and other sources is high in particulate matter and smog-producing chemicals. As a result, air pollution problems, attendant to resulting dust domes and smog, tend to be particularly acute in urban areas, as manifested in part by disproportionately high rates of asthma and other respiratory problems. The flip side of sorts is that dust particles serve as the focus for condensation, leading to production of rain. Thus, urban areas tend to have higher precipitation rates than neighboring rural areas, the rainfall “flushing” the heat and smog from the atmosphere and providing temporary relief from the heat island effect.

The extent of dust domes and smog vary from city to city, and not simply as a function of sizes. Terrain may be a factor. Mexico City and Los Angeles, for example, occupy low-lying lands that are surrounded and partially surrounded respectively by high hills and mountains that contain and concentrate air pollution. Existence and enforcement of environmental law, particularly as it relates to engine emissions, is also a factor.

Finding a place for refuse

Large cities produce large quantities of refuse and sewage and have few solutions regarding their safe disposal. Pursuant to passage of environmental protection laws, ocean dumping is no longer an option, and many cities are running out of sites for landfills within their boundaries. One of the more provocative consequences has been substantial interstate commerce in refuse, in which typically a poor rural county agrees (for a price) to serve as the final resting place for big-city garbage and sewage. Increased use of efficient, high-tech incinerators within cities themselves may be the way of the future, provided they comply with environmental protection laws designed to promote clean air. Even if that happens, however, the contribution of this technology to dust domes, smog, and urban heat islands will be measurable.

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