Street-network Sprawl in Ezakheni, South Africa

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.

Ezakheni: city in KwaZulu-Natal, South Africa

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 Ezakheni, South Africa on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Ezakheni as of 2014, the overall level of street-network sprawl is 3.55, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.21, 3.27, 4.73 and 4.71. Street construction in Ezakheni 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 Ezakheni spans a total of 194 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 3.27, which is highly disconnected.

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 3.21, 3.25, 3.44 and 3.55. Overall, the SNDi of the aggregate street network has risen: the street network in Ezakheni has become more disconnected.

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

How do development practices in Ezakheni fare in comparison to others in KwaZulu-Natal? Most recently in 2001-2014, street construction in Ezakheni was the 7th-most disconnected out of the 9 cities in KwaZulu-Natal. Its position in the ranks since 1975 has fallen; relative to other cities in KwaZulu-Natal, street construction in Ezakheni has become more connected. Ezakheni ranked 4th in 1975, 8th in 1976-1990, 8th in 1991-2000 and 7th in 2001-2014.

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

How do development practices in Ezakheni fare in comparison to others in South Africa? Most recently in 2001-2014, street construction in Ezakheni was the 25th-most disconnected out of the 77 cities in South Africa. Its position in the ranks since 1975 has fallen; relative to other cities in South Africa, street construction in Ezakheni has become more connected. Ezakheni ranked 16th in 1975, 40th in 1976-1990, 20th in 1991-2000 and 25th in 2001-2014.

Ezakheni and KwaZulu-Natal follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Ezakheni is the 8th-most disconnected out of the 9 cities in KwaZulu-Natal. Its position in the ranks since 1975 has fallen; relative to other cities in KwaZulu-Natal, the street network in Ezakheni has become more connected. Ezakheni ranked 4th in 1975, 8th in 1976-1990, 8th in 1991-2000 and 8th in 2001-2014.

Ezakheni and South Africa follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Ezakheni is the 28th-most disconnected out of the 77 cities in South Africa. Its position in the ranks since 1975 has fallen; relative to other cities in South Africa, the street network in Ezakheni has become more connected. Ezakheni ranked 16th in 1975, 35th in 1976-1990, 31st in 1991-2000 and 28th in 2001-2014.

As of 2015, Ezakheni had a built-up area of 2.42 square kilometers, and a population of 54060 people.

These are some other cities with approximately the same population: