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.