Street-network Sprawl in Jega, 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.

Jega: city in Kebbi, 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 Jega, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Jega as of 2014, the overall level of street-network sprawl is 0.83, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are -0.06, 1.69, -0.1 and 0.68. Disconnectivity in street construction in Jega follows a zig-zag trend. In 1991-2000, street construction was most disconnected, while construction was most connected in 1976-1990.

Quantity of street network construction: The street network in Jega spans a total of 169 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 0.68, 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 -0.06, 1.05, 0.94 and 0.83. The aggregate street network in Jega increased in disconnectivity initially,but the trend has turned around after 1990.

Jega and Kebbi do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Jega followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Kebbi peaked in 1991-2000.

How do development practices in Jega fare in comparison to others in Kebbi? Most recently in 2001-2014, street construction in Jega was the 5th-most disconnected out of the 11 cities in Kebbi. Its position in the ranks since 1975 has fallen; relative to other cities in Kebbi, street construction in Jega has become more connected. Jega ranked 2nd in 1975, 1st in 1976-1990, 5th in 1991-2000 and 5th in 2001-2014.

Jega and Nigeria do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Jega followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Nigeria peaked in 1991-2000.

How do development practices in Jega fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Jega was the 308th-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 Jega has become more connected. Jega ranked 205th in 1975, 184th in 1976-1990, 248th in 1991-2000 and 308th in 2001-2014.

Jega and Kebbi do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Jega peaked in 1976-1990, while the SNDi of street constructions in Kebbi rose steadily.

To date, Jega is the 5th-most disconnected out of the 11 cities in Kebbi. Its position in the ranks since 1975 has fallen; relative to other cities in Kebbi, the street network in Jega has become more connected. Jega ranked 2nd in 1975, 2nd in 1976-1990, 3rd in 1991-2000 and 5th in 2001-2014.

Jega and Nigeria do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Jega peaked in 1976-1990, while the SNDi of street constructions in Nigeria rose steadily.

To date, Jega is the 289th-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 Jega has become more connected. Jega ranked 205th in 1975, 219th in 1976-1990, 242nd in 1991-2000 and 289th in 2001-2014.

As of 2015, Jega had a built-up area of 6.06 square kilometers, and a population of 215941 people.

These are some other cities with approximately the same population: