Street-network Sprawl in Vanderbijlpark, 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.

Vanderbijlpark: city in Gauteng, 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 Vanderbijlpark, South Africa on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Vanderbijlpark as of 2014, the overall level of street-network sprawl is 2.46, 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 1.48, 1.88, 3.92 and 3.91. Street construction in Vanderbijlpark 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 Vanderbijlpark spans a total of 841 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 1.88, 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 1.48, 1.77, 2.44 and 2.46. Overall, the SNDi of the aggregate street network has risen: the street network in Vanderbijlpark has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.29 points, but between 1991-2000 and 2001-2014, it rose by just 0.02.

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

How do development practices in Vanderbijlpark fare in comparison to others in Gauteng? Most recently in 2001-2014, street construction in Vanderbijlpark was the 9th-most disconnected out of the 19 cities in Gauteng. Its position in the ranks since 1975 has risen; relative to other cities in Gauteng, street construction in Vanderbijlpark has become more disconnected. Vanderbijlpark ranked 18th in 1975, 17th in 1976-1990, 10th in 1991-2000 and 9th in 2001-2014.

Vanderbijlpark and South Africa do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Vanderbijlpark 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 Vanderbijlpark fare in comparison to others in South Africa? Most recently in 2001-2014, street construction in Vanderbijlpark was the 34th-most disconnected out of the 77 cities in South Africa. Its position in the ranks since 1975 has risen; relative to other cities in South Africa, street construction in Vanderbijlpark has become more disconnected. Vanderbijlpark ranked 54th in 1975, 65th in 1976-1990, 34th in 1991-2000 and 34th in 2001-2014.

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

To date, Vanderbijlpark is the 15th-most disconnected out of the 19 cities in Gauteng. Its position in the ranks since 1975 has risen; relative to other cities in Gauteng, the street network in Vanderbijlpark has become more disconnected. Vanderbijlpark ranked 18th in 1975, 19th in 1976-1990, 15th in 1991-2000 and 15th in 2001-2014.

Vanderbijlpark 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, Vanderbijlpark is the 58th-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 Vanderbijlpark has become more connected. Vanderbijlpark ranked 54th in 1975, 67th in 1976-1990, 57th in 1991-2000 and 58th in 2001-2014.

As of 2015, Vanderbijlpark had a built-up area of 38.39 square kilometers, and a population of 217223 people.

These are some other cities with approximately the same population: