Urban Models and Structure

Understanding how cities are organised internally is a fundamental component of AQA A-Level Geography. Urban models attempt to simplify the complex reality of land use patterns within cities, providing frameworks for analysis and comparison. This lesson examines the classical models, their strengths and limitations, and more contemporary critiques from the Los Angeles School of urbanism.

The Burgess Concentric Zone Model (1925)

Ernest Burgess developed his model based on observations of Chicago in the 1920s. He proposed that cities grow outward from a central point in a series of concentric rings, each characterised by a distinct land use and social group.

The Five Zones

Zone	Name	Characteristics
1	Central Business District (CBD)	Commercial heart; highest land values; offices, shops, entertainment; vertical growth; few permanent residents
2	Transition Zone (Zone of Transition)	Mixed land use; older housing converted to flats/offices; light industry; immigrant communities; deteriorating buildings; highest crime rates
3	Zone of Working-Class Homes	Terraced housing; stable, lower-income families who have moved out of Zone 2; close to factories for commuting
4	Zone of Better Residences	Semi-detached and detached housing; middle-class families; better environmental quality; owner-occupied properties
5	Commuter Zone (Suburbs)	Low-density housing; highest income groups; large gardens; car-dependent; dormitory settlements beyond the continuous built-up area

Burgess argued that cities expand through a process of invasion and succession — as new migrants arrive in the transition zone, established residents move outward, each group displacing the one ahead of it.

Evaluation of the Burgess Model

Strengths:

Provides a clear, simple framework for understanding urban structure
Recognises the role of migration and social mobility in shaping residential patterns
The concept of the transition zone remains relevant in many cities (e.g., inner-city areas of Birmingham, Manchester)
Useful starting point for comparative analysis

Limitations:

Based on a single American city (Chicago) in a specific historical period
Assumes a flat, featureless plain with no physical barriers (rivers, hills)
Ignores the role of planning, zoning regulations, and government intervention
Does not account for multiple centres of economic activity
Oversimplifies the complexity of ethnic and social segregation
Transport networks (railways, motorways) distort the concentric pattern

Exam Tip: Never simply describe a model — always evaluate it. Examiners reward candidates who can explain why models are useful despite their simplifications, and who can apply them to real places.

The Hoyt Sector Model (1939)

Homer Hoyt modified Burgess's model by arguing that land use is arranged not in concentric rings but in sectors or wedges radiating outward from the CBD along transport routes.

Key Principles

High-income residential areas tend to develop along prestigious routes (e.g., along a ridge with good views, or along a main road leading to attractive countryside)
Industrial areas develop along transport corridors — railways, canals, major roads — creating wedge-shaped zones extending from the city centre
Low-income housing clusters near industrial zones due to lower land values and proximity to employment
Once a sector is established, it tends to maintain its character as the city grows, extending outward along the same axis

Application to UK Cities

Hoyt's model applies well to many British cities:

In Leeds, industry historically developed along the Aire Valley (canal and railway corridor), with wealthier suburbs to the north (Headingley, Roundhay) and lower-income areas to the east and south
In Newcastle, prestigious residential areas developed northward (Jesmond, Gosforth), while industry concentrated along the Tyne

Evaluation

Strengths:

Recognises the influence of transport routes on urban form
More realistic than Burgess for cities with strong linear transport corridors
Explains why similar land uses cluster together (agglomeration economies)

Limitations:

Still assumes a single CBD
Does not fully account for post-industrial restructuring
Council housing estates often break the sector pattern (e.g., peripheral estates built by local authorities)
Gentrification can transform low-income sectors

The Harris and Ullman Multiple Nuclei Model (1945)

Chauncy Harris and Edward Ullman proposed that cities do not grow from a single centre but develop around multiple nuclei — separate centres of activity that attract specific land uses.

Core Ideas

Certain activities require specialised facilities — e.g., manufacturing needs flat land and transport links; retailing needs accessibility
Similar activities cluster together for mutual benefit (agglomeration) — e.g., financial services in the City of London
Incompatible activities repel each other — e.g., heavy industry and high-income housing rarely coexist
Some activities cannot afford prime locations — e.g., warehousing is pushed to cheaper peripheral sites

Examples of Multiple Nuclei

Nucleus	Function	UK Example
CBD	Retail, offices, services	Manchester city centre
Industrial estate	Manufacturing, distribution	Trafford Park, Manchester
Retail park	Out-of-town shopping	Meadowhall, Sheffield
University campus	Education, student housing	Oxford, Cambridge
Airport	Transport, logistics, hotels	Heathrow corridor

Evaluation

This model is arguably the most realistic of the three classical models, as it acknowledges the polycentric nature of modern cities. However, it is descriptive rather than explanatory — it identifies patterns but does not fully explain why nuclei form where they do.

Mann's Model of a British City (1965)

Peter Mann adapted the Burgess and Hoyt models specifically for British cities, recognising the influence of prevailing south-westerly winds and local authority housing.

Key Features

Combines concentric zones (Burgess) with sectors (Hoyt)
The west side of the city tends to be higher status because prevailing winds carry industrial pollution eastward
Council housing estates appear as distinct sectors, often on the urban periphery — a feature absent from American models
The transition zone is less pronounced in British cities due to stronger planning controls

Application

Mann's model applies well to cities such as Sunderland, Middlesbrough, and Nottingham, where:

Industry developed to the east (downwind)
Wealthier suburbs developed to the west and south-west
Large council estates were built on peripheral greenfield sites in the post-war period

Bid-Rent Theory

Bid-rent theory explains urban land use patterns through economic competition for land. Different land users are willing and able to pay different amounts for land at varying distances from the city centre.

The Bid-Rent Curve

Commercial users (shops, offices) can pay the highest rents and need central, accessible locations — they dominate the CBD
Industrial users need larger areas of cheaper land — they locate in intermediate zones or along transport routes
Residential users are willing to trade off accessibility for space — they dominate suburban areas

The result is a pattern where land values decline with distance from the CBD, and land use zones form as different users outbid each other at different distances.

Modifications to the Basic Model

Transport intersections create secondary peaks in land values (e.g., around suburban railway stations)
Planning restrictions (green belts, conservation areas) distort the bid-rent curve
Gentrification raises residential land values in inner-city areas, challenging the simple decline with distance

A-Level Analysis: Bid-rent theory links urban geography to economic theory. It explains why CBDs have tall buildings (maximising floor space on expensive land), why suburbs are low-density, and why out-of-town retail parks develop where land is cheap but motorway access is good.

The Post-Modern City and the Los Angeles School

Since the 1990s, geographers associated with the Los Angeles School (notably Michael Dear and Edward Soja) have challenged classical urban models.

Key Arguments

The CBD is no longer the organising centre of the city — in post-modern cities like Los Angeles, development is dispersed, polycentric, and driven by motorway intersections rather than a single downtown
Classical models assumed orderly growth from the centre outward — the LA School argues that the periphery now organises the centre, reversing the traditional relationship
Globalisation, migration, and cultural diversity create a fragmented urban landscape that cannot be captured by simple concentric or sector models
Gated communities, edge cities, and ethnoburbs produce a mosaic of disconnected urban spaces rather than a coherent spatial structure

Edward Soja's Six Geographies of the Post-Metropolis

Soja (2000) identified six restructuring processes shaping post-modern cities:

Flexcity — the shift from Fordist mass production to flexible, post-industrial economies
Cosmopolis — the increasing cultural diversity driven by global migration
Exopolis — the growth of edge cities and suburban centres that rival the traditional CBD
Fractal City — increasing social polarisation and spatial inequality
Carceral Archipelago — the rise of surveillance, gated communities, and fortress architecture
Simcity — the blurring of real and imagined urban spaces through media and simulation

Evaluation of the LA School

Strengths:

Reflects the reality of many contemporary cities, particularly in North America
Acknowledges the role of globalisation, technology, and cultural change
Challenges Eurocentric assumptions in classical models

Limitations:

Based primarily on Los Angeles — may not apply to European or Asian cities
Can be overly theoretical and difficult to apply empirically
Classical models remain useful starting points, even if they require modification

Summary and Synoptic Links

Model	Key Idea	Main Limitation
Burgess (1925)	Concentric zones; invasion and succession	Single centre; flat plain assumption
Hoyt (1939)	Sectors along transport routes	Does not account for multiple centres
Harris & Ullman (1945)	Multiple nuclei	Descriptive, not explanatory
Mann (1965)	UK adaptation; wind direction; council housing	Limited to industrial British cities
Bid-rent theory	Economic competition for land	Assumes rational actors; ignores planning
LA School	Post-modern, polycentric, fragmented	Based on one city; overly theoretical

Synoptic links:

Globalisation (AQA 3.2.5) — global economic forces shape urban structure
Changing Places (AQA 3.2.4) — sense of place varies across urban zones
Population and the Environment — migration drives urban growth patterns

Exam Tip: In 20-mark essays, demonstrate synopticity by linking urban models to broader geographical processes. For example, explain how globalisation has made the multiple nuclei model more relevant as cities develop polycentric structures around airport hubs, business parks, and retail centres.