Street-network Sprawl in Bombouaka, Togo

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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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Bombouaka: city in Savanes, Togo

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 Bombouaka, Togo on the sprawlmap

How have Bombouaka's street networks changed over time?

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Bombouaka as of 2014, the overall level of street-network sprawl is 5.9, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are nan, 7.74, nan and nan. Data was not available in 1975, 1991-2000 and 2001-2014.

Quantity of street network construction: The street network in Bombouaka spans a total of 11 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of nan, 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 nan, 7.74, 7.74 and 5.9. Data was not available in 1975.

Bombouaka in context: Street-network sprawl of new development

Bombouaka and Savanes 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 Savanes rose steadily.

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

Bombouaka and Togo 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 Togo rose steadily.

How do development practices in Bombouaka fare in comparison to others in Togo? out of the 20 cities in Togo. Bombouaka ranked 1st in 1976-1990. There was no ranking in 1975, 1991-2000, and 2001-2014 due to unavailable data.

Bombouaka in context: Aggregate street-network sprawl

Bombouaka and Savanes do not follow the same trend in the disconnectivity of their aggregate street networks. There was not enough data from the city, while the SNDi of street constructions in Savanes rose steadily.

To date, Bombouaka is the 1st-most disconnected out of the 4 cities in Savanes. Its position in the ranks since 1975 has not changed. Bombouaka ranked 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014. There was no ranking in 1975 due to unavailable data.

Bombouaka and Togo do not follow the same trend in the disconnectivity of their aggregate street networks. There was not enough data from the city, while the SNDi of street constructions in Togo rose steadily.

To date, Bombouaka is the 1st-most disconnected out of the 20 cities in Togo. Its position in the ranks since 1975 has not changed. Bombouaka ranked 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014. There was no ranking in 1975 due to unavailable data.

What about other similarly-populated cities?

As of 2015, Bombouaka had a built-up area of 0.05 square kilometers, and a population of 86070 people.

These are some other cities with approximately the same population:

• Brianka, Ukraine
• Dhanaura, India
• Bundu, India