Street-network Sprawl in Tudun Wada, Nigeria

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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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Tudun Wada: city in Kano, Nigeria

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 Tudun Wada, Nigeria on the sprawlmap

How have Tudun Wada's street networks changed over time?

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Tudun Wada as of 2014, the overall level of street-network sprawl is -0.51, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are -0.44, -0.67, nan and -0.52. Data was not available in 1991-2000.

Quantity of street network construction: The street network in Tudun Wada spans a total of 98 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of -0.52, which is very well-connected.

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 -0.44, -0.55, -0.55 and -0.51. The SNDi of the aggregate street network in fell at first, but Tudun Wada has worsened in disconnectivity since 1990.

Tudun Wada in context: Street-network sprawl of new development

Tudun Wada and Kano 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 Kano peaked in 1976-1990.

How do development practices in Tudun Wada fare in comparison to others in Kano? Most recently in 2001-2014, street construction in Tudun Wada was the 17th-most disconnected out of the 22 cities in Kano. Its position in the ranks since 1975 has fallen; relative to other cities in Kano, street construction in Tudun Wada has become more connected. Tudun Wada ranked 13th in 1975, 14th in 1976-1990 and 17th in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

Tudun Wada and Nigeria 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 Nigeria peaked in 1991-2000.

Tudun Wada in context: Aggregate street-network sprawl

Tudun Wada and Kano do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Tudun Wada was at its lowest in 1976-1990, while the SNDi of street constructions in Kano rose steadily.

To date, Tudun Wada is the 19th-most disconnected out of the 22 cities in Kano. Its position in the ranks since 1975 has fallen; relative to other cities in Kano, the street network in Tudun Wada has become more connected. Tudun Wada ranked 13th in 1975, 17th in 1976-1990, 17th in 1991-2000 and 19th in 2001-2014.

Tudun Wada and Nigeria do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Tudun Wada was at its lowest in 1976-1990, while the SNDi of street constructions in Nigeria rose steadily.

What about other similarly-populated cities?

As of 2015, Tudun Wada had a built-up area of 1.96 square kilometers, and a population of 87451 people.

These are some other cities with approximately the same population:

• Kuala Tungkal, Indonesia
• Pingjiang, China
• Rajnagar, India