Street-network Sprawl in Cauca, Colombia

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.

Cauca: region in Colombia

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 Cauca, Colombia on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Cauca as of 2014, the overall level of street-network sprawl is 3.74, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.43, nan, 5.28 and 6.6. Data was not available in 1976-1990.

Quantity of street network construction: The street network in Cauca spans a total of 4263 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 3.43, 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 3.43, 3.43, 3.61 and 3.74. Overall, the SNDi of the aggregate street network has risen: the street network in Cauca has become more disconnected.

The level of street-network sprawl in new development in Cauca followed a zig-zag trend with an overall increase. To get a sense of how street development has changed in Cauca, we can consider two of its most populous cities: Popayán and Santander de Quilichao. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Popayán followed a zig-zag trend with an overall increase. The level of street-network sprawl in new development in Santander de Quilichao followed a zig-zag trend with an overall decrease.

How do development practices in Cauca fare in comparison to others in Colombia? Most recently in 2001-2014, street construction in Cauca was the 6th-most disconnected out of the 28 regions in Colombia. Its position in the ranks since 1975 has risen; relative to other regions in Colombia, street construction in Cauca has become more disconnected. Cauca ranked 8th in 1975, 7th in 1991-2000 and 6th in 2001-2014. There was no ranking in 1976-1990 due to unavailable data.

As of 2014, the city with the most disconnected street network in Cauca is Popayán with an SNDi of 2.2, which is relatively well-connected. Conversely, the most connected city is Santander de Quilichao with an SNDi of 2.03, which is relatively well-connected. See trends for these cities: Santander de Quilichao, Popayán

The level of street-network sprawl in the aggregate network in Cauca rose steadily. To get a sense of how the aggregate street network has changed in Cauca, we can consider two of its most populous cities: Popayán and Santander de Quilichao. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Popayán rose steadily. The level of street-network sprawl in the aggregate network in Santander de Quilichao followed a zig-zag trend with an overall increase.

To date, Cauca is the 8th-most disconnected out of the 28 regions in Colombia. Its position in the ranks since 1975 has not changed. Cauca ranked 8th in 1975, 8th in 1976-1990, 8th in 1991-2000 and 8th in 2001-2014.