Street-network Sprawl in Angola

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.

Angola

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 Angola on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Angola as of 2014, the overall level of street-network sprawl is 3.05, which is in the 40th to 60th percentile of disconnectedness.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.86, 3.54, 3.5 and 2.81. Street construction in Angola increased in disconnectivity initially but has since improved. The streets constructed in 1976-1990 were the most disconnected.

Quantity of street network construction: The street network in Angola spans a total of 85363 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 2.81, 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 2.86, 3.19, 3.31 and 3.05. The aggregate street network in Angola increased in disconnectivity initially,but the trend has turned around after 2000.

The level of street-network sprawl in new development in Angola peaked in 1976-1990. To get a sense of how street development has changed in Angola, we can consider three of its most populous regions: Luanda, Huíla and Benguela. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Luanda followed a zig-zag trend with an overall decrease. The level of street-network sprawl in new development in Huíla peaked in 1991-2000. The level of street-network sprawl in new development in Benguela was at its lowest in 1991-2000.

How do development practices in Angola fare in comparison to others in the world? Most recently in 2001-2014, street construction in Angola was the 133rd-most disconnected out of the 155 countries in the world. Its position in the ranks since 1975 has fallen; relative to other countries in the world, street construction in Angola has become more connected. Angola ranked 76th in 1975, 63rd in 1976-1990, 109th in 1991-2000 and 133rd in 2001-2014.

The largest city in Angola is Luanda, with a population of 6787000 people. Taking into account the entire (i.e. aggregate) street network in Luanda as of 2014, the overall level of street-network sprawl is 1.6, which is relatively well-connected. The level of street-network sprawl in new development in Luanda followed a zig-zag trend with an overall decrease.

As of 2014, the city with the most disconnected street network in Angola is M'banza Congo with an SNDi of 6.9, which is highly disconnected. Conversely, the most connected city is Caluquembe with an SNDi of -0.99, which is very well-connected. See trends for these cities: Caluquembe, M'banza Congo

The level of street-network sprawl in the aggregate network in Angola peaked in 1991-2000. To get a sense of how the aggregate street network has changed in Angola, we can consider three of its most populous regions: Luanda, Huíla and Benguela. Out of the three regions, Luanda and Benguela do not follow the same trend as the country. The level of street-network sprawl in the aggregate network in Luanda followed a zig-zag trend with an overall decrease. The level of street-network sprawl in the aggregate network in Benguela fell steadily.

To date, Angola is the 91st-most disconnected out of the 155 countries in the world. Its position in the ranks since 1975 has fallen; relative to other countries in the world, the street network in Angola has become more connected. Angola ranked 76th in 1975, 73rd in 1976-1990, 74th in 1991-2000 and 91st in 2001-2014.

The largest city in Angola is Luanda, with a population of 6787000 people. Taking into account the entire (i.e. aggregate) street network in Luanda as of 2014, the overall level of street-network sprawl is 1.6, which is relatively well-connected. The level of street-network sprawl in the aggregate network in Luanda fell steadily.