Street-network Sprawl in Republic of Congo

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.

Republic of Congo

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 Republic of Congo on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Republic of Congo as of 2014, the overall level of street-network sprawl is 3.83, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.72, 3.88, 4.59 and 6.19. In each period, new street development in Republic of Congo steadily grows more disconnected than in the last.

Quantity of street network construction: The street network in Republic of Congo spans a total of 26290 kilometers. The period with the greatest volume of street construction was 1975. These roads have an SNDi of 2.72, which is in the 40th to 60th percentile of disconnectedness.

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 2.72, 2.97, 3.31 and 3.83. Overall, the SNDi of the aggregate street network has risen: the street network in Republic of Congo has become more disconnected.

The level of street-network sprawl in new development in Republic of Congo rose steadily. To get a sense of how street development has changed in Republic of Congo, we can consider three of its most populous regions: Brazzaville, Pointe Noire and Likouala. Out of the three regions, Brazzaville and Pointe Noire do not follow the same trend as the country. The level of street-network sprawl in new development in Brazzaville followed a zig-zag trend with an overall decrease. The level of street-network sprawl in new development in Pointe Noire followed a zig-zag trend.

How do development practices in Republic of Congo fare in comparison to others in the world? Most recently in 2001-2014, street construction in Republic of Congo was the 25th-most disconnected out of the 155 countries in the world. Its position in the ranks since 1975 has risen; relative to other countries in the world, street construction in Republic of Congo has become more disconnected. Republic of Congo ranked 80th in 1975, 54th in 1976-1990, 61st in 1991-2000 and 25th in 2001-2014.

The largest city in Republic of Congo is Brazzaville, with a population of 1636000 people. Taking into account the entire (i.e. aggregate) street network in Brazzaville as of 2014, the overall level of street-network sprawl is 1.99, which is relatively well-connected. The level of street-network sprawl in new development in Brazzaville peaked in 1991-2000.

As of 2014, the city with the most disconnected street network in Republic of Congo is Pointe-Noire with an SNDi of 2.27, which is in the 40th to 60th percentile of disconnectedness. Conversely, the most connected city is Bétou with an SNDi of -0.44, which is very well-connected. See trends for these cities: Bétou, Pointe-Noire

The level of street-network sprawl in the aggregate network in Republic of Congo rose steadily. To get a sense of how the aggregate street network has changed in Republic of Congo, we can consider three of its most populous regions: Brazzaville, Pointe Noire and Likouala. Out of the three regions, Brazzaville and Pointe Noire do not follow the same trend as the country. The level of street-network sprawl in the aggregate network in Brazzaville followed a zig-zag trend with an overall decrease. The level of street-network sprawl in the aggregate network in Pointe Noire rose steadily.

To date, Republic of Congo is the 59th-most disconnected out of the 155 countries in the world. Its position in the ranks since 1975 has risen; relative to other countries in the world, the street network in Republic of Congo has become more disconnected. Republic of Congo ranked 80th in 1975, 85th in 1976-1990, 71st in 1991-2000 and 59th in 2001-2014.

The largest city in Republic of Congo is Brazzaville, with a population of 1636000 people. Taking into account the entire (i.e. aggregate) street network in Brazzaville as of 2014, the overall level of street-network sprawl is 1.99, which is relatively well-connected. The level of street-network sprawl in the aggregate network in Brazzaville rose steadily.