Street-network Sprawl in Ebolowa, Cameroon

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What is Street-network sprawl?

Street-network Sprawl is a way to measure urban sprawl, worldwide, through the connectedness of the streets. Less sprawl means more connected, more walkable streets. Well-connected streets – like New York City’s grid – are more walkable and can be served by public transit.

The street network is permanent, and its connectivity affects the livability and environmental footprint of cities for decades and centuries to come. In places with more connected streets, residents drive less and walk more. A well-connected street network is associated with better outcomes for health, the environment, sustainable consumption, social integration, and equity.

We can quantify how connected street networks are with the Street Network Disconnectedness Index (SNDi).

SNDi -- our measure of street-network sprawl (disconnectedness)

The SNDi is a comprehensive measurement of “sprawl”. It captures:

• nodal degree
• dendricity, the tree-likeness of the street network
• circuity, the ratio of the distance by road to the straight-line distance of two locations on the street network
• sinuosity, the curviness of a street

A higher SNDi means less-connected streets – i.e., more sprawl. For the 10137 cities in our dataset, the average SNDi is 2.25, with half of the cities' SNDis falling between 1.08 and 3.25.

More information on the sprawl index can be found in these research papers:

• Global trends toward urban street-network sprawl
• A global assessment of street-network sprawl

To see the state of street-network sprawl across the globe, visit the sprawlmap.

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Ebolowa: city in Sud, Cameroon

What exactly constitutes the spatial extent of the city? For these aggregations, we used the Global Human Settlement Layer Urban Center Database (GHS-UCDB) to define the boundaries of the city. These cities -- or urban centers -- cover areas that are densely populated and built-up, and so may extend beyond the spatial borders of these cities that we may be familiar with. The GHS area is shaded in blue.

View Ebolowa, Cameroon on the sprawlmap

How have Ebolowa's street networks changed over time?

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Ebolowa as of 2014, the overall level of street-network sprawl is 5.3, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 5.97, nan, 4.83 and nan. Data was not available in 1976-1990 and 2001-2014.

Quantity of street network construction: The street network in Ebolowa spans a total of 163 kilometers. It is dominated by roads constructed in 1991-2000. These roads have an SNDi of 4.83, which is highly disconnected.

Effect on the aggregate network: New construction in each period adds to the total stock of streets, but does not change streets that have already been built. Therefore, it has a limited effect on the street network as a whole. The SNDis of the aggregate street network in the respective time periods are 5.97, 5.97, 5.3 and 5.3. Overall, the SNDi of the aggregate street network has fallen: the street network in Ebolowa has become more connected.

Ebolowa in context: Street-network sprawl of new development

Ebolowa and Sud do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, as well as the Sud's street network construction.

How do development practices in Ebolowa fare in comparison to others in Sud? out of the 4 cities in Sud. Ebolowa ranked 1st in 1975 and 2nd in 1991-2000. There was no ranking in 1976-1990 and 2001-2014 due to unavailable data.

Ebolowa and Cameroon do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in Cameroon rose steadily.

How do development practices in Ebolowa fare in comparison to others in Cameroon? out of the 51 cities in Cameroon. Ebolowa ranked 1st in 1975 and 9th in 1991-2000. There was no ranking in 1976-1990 and 2001-2014 due to unavailable data.

Ebolowa in context: Aggregate street-network sprawl

Ebolowa and Sud do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Ebolowa fell steadily, while the SNDi of street constructions in Sud followed a zig-zag trend with an overall increase.

To date, Ebolowa is the 1st-most disconnected out of the 4 cities in Sud. Its position in the ranks since 1975 has not changed. Ebolowa ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

Ebolowa and Cameroon do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Ebolowa fell steadily, while the SNDi of street constructions in Cameroon rose steadily.

To date, Ebolowa is the 3rd-most disconnected out of the 51 cities in Cameroon. Its position in the ranks since 1975 has fallen; relative to other cities in Cameroon, the street network in Ebolowa has become more connected. Ebolowa ranked 1st in 1975, 1st in 1976-1990, 3rd in 1991-2000 and 3rd in 2001-2014.

What about other similarly-populated cities?

As of 2015, Ebolowa had a built-up area of 2.98 square kilometers, and a population of 171573 people.

These are some other cities with approximately the same population:

• Jieshi, China
• Toruń, Poland
• Linquan, China