Sub Saharan City Model

The Sub-Saharan African city model is an urban structure model showing cities organized around three separate CBDs (colonial, traditional, and market), with ethnic neighborhoods beyond them and informal squatter settlements on the periphery, reflecting both colonial history and rapid recent urbanization.

What is Sub Saharan City Model?

The Sub-Saharan African city model (often credited to geographer Harm de Blij) is one of the regional urban models the CED names alongside the Latin American and Southeast Asian models. Its signature feature is that there isn't one downtown. There are three CBDs sitting side by side: a colonial CBD with vertical buildings and formal businesses left over from European rule, a traditional CBD with older, single-story buildings and small shops, and an open-air market zone (sometimes called the periodic market) where informal commerce happens.

Moving outward, you hit ethnic and mixed neighborhoods, then mining and manufacturing zones, and finally informal satellite townships and squatter settlements on the edge of the city. That outer ring matters. Sub-Saharan African cities are urbanizing faster than housing and infrastructure can keep up, so newcomers build informal settlements on the periphery without legal title, running water, or sewage systems. The model is basically colonial history and rapid modern urbanization stamped onto the same map.

Why Sub Saharan City Model matters in AP Human Geography

This model lives in Topic 6.5 (The Internal Structure of Cities) in Unit 6 and directly supports learning objective 6.5.A: explain the internal structure of cities using various models and theories. EK PSO-6.D.1 explicitly lists "urban models drawn from Latin America, Southeast Asia, and Africa" next to Burgess, Hoyt, Harris and Ullman, the galactic city model, and bid-rent theory. Translation: the College Board expects you to know the regional models, not just the classic American ones.

The Sub-Saharan model also does double duty as evidence. It's a concrete example of how colonial legacy shapes spatial patterns and how informal economies and squatter settlements emerge in rapidly urbanizing developing countries, which are themes that echo through the rest of Unit 6 and into Unit 7's development content.

How Sub Saharan City Model connects across the course

Burgess Concentric Zone Model (Unit 6)

Burgess assumed one CBD with rings of decreasing land value moving outward, based on 1920s Chicago. The Sub-Saharan model breaks that assumption with three competing CBDs, which is exactly the kind of model-comparison the exam loves. Knowing why a North American model fails to describe Lagos or Nairobi is the point of learning regional models.

Colonial Legacy (Unit 6)

The colonial CBD exists because European powers built formal commercial districts for their own administrators and businesses. After independence, that district didn't disappear; it just sits next to the traditional and market CBDs. The model is physical proof that colonialism leaves a spatial footprint long after the colonizers leave.

Informal Economy (Unit 6)

The open-air market zone and the peripheral squatter settlements both run on informal economic activity, meaning unregulated, untaxed work like street vending. In many Sub-Saharan cities, the informal sector employs more people than the formal one, and this model shows you exactly where that activity concentrates.

Urbanization in Developing Countries (Units 6-7)

Sub-Saharan Africa has some of the fastest urban growth rates in the world, driven by rural-to-urban migration. The squatter settlements on the model's edge are what happens when population growth outpaces housing supply, linking this model to development indicators and challenges covered in Unit 7.

Is Sub Saharan City Model on the AP Human Geography exam?

Multiple-choice questions typically test whether you can identify the model's defining feature (three CBDs) or match it to its region, often by showing a diagram and asking which model it represents or which city it best describes. You may also get a stem comparing it to the Latin American or Southeast Asian model.

No released FRQ has asked about this model by name, but FRQs on urban structure regularly ask you to explain why classic models like Burgess don't fit cities in the periphery, or to describe challenges of squatter settlements. The Sub-Saharan model gives you ready-made evidence for both. If an FRQ asks you to explain a city model's structure (LO 6.5.A), be ready to name the three CBDs and the informal settlements on the edge, and connect them to colonialism and rapid urbanization rather than just listing zones.

Sub Saharan City Model vs Latin American City Model (Griffin-Ford)

Both are regional models shaped by colonial history with squatter settlements on the periphery, so they're easy to mix up. The key difference is downtown. The Latin American model has ONE central CBD with a commercial spine extending outward toward an elite sector. The Sub-Saharan model has THREE distinct CBDs (colonial, traditional, and market) sitting near each other. If a question shows multiple central business districts, it's the Sub-Saharan model. If it shows a spine and a plaza-centered core, it's Latin American.

Key things to remember about Sub Saharan City Model

• The Sub-Saharan African city model's defining feature is three separate CBDs: a colonial CBD, a traditional CBD, and an open-air market zone.

• Informal squatter settlements sit on the periphery of the model, the result of urban populations growing faster than formal housing and infrastructure.

• The model shows colonial legacy in physical form, since the colonial CBD was built by and for European powers and still anchors the city after independence.

• EK PSO-6.D.1 names urban models drawn from Africa alongside Burgess, Hoyt, multiple-nuclei, the galactic city model, and bid-rent theory, so it's fair game on the exam.

• The fastest way to tell it apart from the Latin American model is to count the CBDs: three means Sub-Saharan, one with a commercial spine means Latin American.

Frequently asked questions about Sub Saharan City Model

What is the Sub-Saharan African city model in AP Human Geography?

It's an urban model showing cities in Sub-Saharan Africa organized around three CBDs (colonial, traditional, and open-air market), surrounded by ethnic neighborhoods, mining and manufacturing zones, and informal squatter settlements on the periphery. It falls under Topic 6.5, The Internal Structure of Cities.

How is the Sub-Saharan city model different from the Latin American city model?

The Latin American (Griffin-Ford) model has one central CBD with a commercial spine running to an elite sector. The Sub-Saharan model has three distinct CBDs instead. Both feature peripheral squatter settlements and colonial influence, which is why they get confused.

Does the Sub-Saharan city model only have one CBD?

No, and that's the whole point. It has three: a vertical colonial CBD built during European rule, a traditional CBD with older single-story buildings, and an informal open-air market zone. Multiple CBDs is the model's signature on the exam.

Is the Sub-Saharan city model on the AP Human Geography exam?

Yes. EK PSO-6.D.1 explicitly lists urban models drawn from Africa as required content for explaining the internal structure of cities (LO 6.5.A), so it can appear in multiple-choice questions or as evidence in urban-structure FRQs.

Why are squatter settlements on the edge of Sub-Saharan African cities?

Rural-to-urban migration is happening faster than cities can build formal housing, so newcomers settle informally on cheap peripheral land without legal ownership or services like water and sewage. The model places these settlements in the outermost ring.