Street-network Sprawl in Sangasumi, Nigeria

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:

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:

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

Sangasumi: city in Adamawa, 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 Sangasumi, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sangasumi as of 2014, the overall level of street-network sprawl is 1.14, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.93, 1.28, 1.48 and 1.05. Street construction in Sangasumi increased in disconnectivity initially but has since improved. The streets constructed in 1991-2000 were the most disconnected.

Quantity of street network construction: The street network in Sangasumi spans a total of 68 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 1.05, which is relatively 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 0.93, 1.09, 1.2 and 1.14. The aggregate street network in Sangasumi increased in disconnectivity initially,but the trend has turned around after 2000.

Sangasumi and Adamawa do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Sangasumi peaked in 1991-2000, while the SNDi of street constructions in Adamawa rose steadily.

How do development practices in Sangasumi fare in comparison to others in Adamawa? Most recently in 2001-2014, street construction in Sangasumi was the 11th-most disconnected out of the 17 cities in Adamawa. Its position in the ranks since 1975 has fallen; relative to other cities in Adamawa, street construction in Sangasumi has become more connected. Sangasumi ranked 4th in 1975, 6th in 1976-1990, 8th in 1991-2000 and 11th in 2001-2014.

Sangasumi and Nigeria follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these peaked in 1991-2000.

How do development practices in Sangasumi fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Sangasumi was the 287th-most disconnected out of the 411 cities in Nigeria. Its position in the ranks since 1975 has fallen; relative to other cities in Nigeria, street construction in Sangasumi has become more connected. Sangasumi ranked 149th in 1975, 216th in 1976-1990, 183rd in 1991-2000 and 287th in 2001-2014.

Sangasumi and Adamawa do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Sangasumi peaked in 1991-2000, while the SNDi of street constructions in Adamawa rose steadily.

To date, Sangasumi is the 8th-most disconnected out of the 17 cities in Adamawa. Its position in the ranks since 1975 has fallen; relative to other cities in Adamawa, the street network in Sangasumi has become more connected. Sangasumi ranked 4th in 1975, 6th in 1976-1990, 6th in 1991-2000 and 8th in 2001-2014.

Sangasumi and Nigeria do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Sangasumi peaked in 1991-2000, while the SNDi of street constructions in Nigeria rose steadily.

To date, Sangasumi is the 261st-most disconnected out of the 411 cities in Nigeria. Its position in the ranks since 1975 has fallen; relative to other cities in Nigeria, the street network in Sangasumi has become more connected. Sangasumi ranked 149th in 1975, 213th in 1976-1990, 220th in 1991-2000 and 261st in 2001-2014.

As of 2015, Sangasumi had a built-up area of 2.25 square kilometers, and a population of 187894 people.

These are some other cities with approximately the same population: