Street-network Sprawl in Nola, Central African Republic

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.

Nola: city in Sangha-Mbaéré, Central African Republic

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 Nola, Central African Republic on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Nola as of 2014, the overall level of street-network sprawl is 1.12, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.55, 1.46, nan and nan. Data was not available in 1991-2000 and 2001-2014.

Quantity of street network construction: The street network in Nola spans a total of 32 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 1.46, 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 0.55, 1.06, 1.08 and 1.12. Overall, the SNDi of the aggregate street network has risen: the street network in Nola has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.51 points, but between 1991-2000 and 2001-2014, it rose by just 0.04.

Nola and Sangha-Mbaéré 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 Sangha-Mbaéré followed a zig-zag trend with an overall increase.

How do development practices in Nola fare in comparison to others in Sangha-Mbaéré? out of the 1 cities in Sangha-Mbaéré. Its position in the ranks since 1975 has not changed. Nola ranked 1st in 1975 and 1st in 1976-1990. There was no ranking in 1991-2000 and 2001-2014 due to unavailable data.

Nola and Central African Republic 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 Central African Republic peaked in 1991-2000.

How do development practices in Nola fare in comparison to others in Central African Republic? out of the 7 cities in Central African Republic. Its position in the ranks since 1975 has risen; relative to other cities in Central African Republic, street construction in Nola has become more disconnected. Nola ranked 7th in 1975 and 3rd in 1976-1990. There was no ranking in 1991-2000 and 2001-2014 due to unavailable data.

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

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

Nola and Central African Republic follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Nola is the 7th-most disconnected out of the 7 cities in Central African Republic. Its position in the ranks since 1975 has not changed. Nola ranked 7th in 1975, 7th in 1976-1990, 7th in 1991-2000 and 7th in 2001-2014.

As of 2015, Nola had a built-up area of 2.19 square kilometers, and a population of 53548 people.

These are some other cities with approximately the same population: