Street-network Sprawl in Sar-e Pol, Afghanistan

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.

Sar-e Pol: city in Sari Pul, Afghanistan

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 Sar-e Pol, Afghanistan on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sar-e Pol 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 3.79, nan, nan and 2.14. Data was not available in 1976-1990 and 1991-2000.

Quantity of street network construction: The street network in Sar-e Pol spans a total of 64 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 3.79, 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 3.79, 3.78, 3.78 and 3.74. Overall, the SNDi of the aggregate street network has fallen: the street network in Sar-e Pol has become more connected. This decrease has quickened: between 1975 and 1976-1990, SNDi fell by 0.01 points, but between 1991-2000 and 2001-2014, it fell by just 0.04.

Sar-e Pol and Sari Pul do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, as well as the Sari Pul's street network construction.

How do development practices in Sar-e Pol fare in comparison to others in Sari Pul? Most recently in 2001-2014, street construction in Sar-e Pol was the 2nd-most disconnected out of the 2 cities in Sari Pul. Sar-e Pol ranked 1st in 1975 and 2nd in 2001-2014. There was no ranking in 1976-1990 and 1991-2000 due to unavailable data.

Sar-e Pol and Afghanistan do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in Afghanistan followed a zig-zag trend with an overall decrease.

How do development practices in Sar-e Pol fare in comparison to others in Afghanistan? Most recently in 2001-2014, street construction in Sar-e Pol was the 14th-most disconnected out of the 40 cities in Afghanistan. Sar-e Pol ranked 8th in 1975 and 14th in 2001-2014. There was no ranking in 1976-1990 and 1991-2000 due to unavailable data.

Sar-e Pol and Sari Pul do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Sar-e Pol fell steadily, while the SNDi of street constructions in Sari Pul peaked in 1991-2000.

To date, Sar-e Pol is the 2nd-most disconnected out of the 2 cities in Sari Pul. Its position in the ranks since 1975 has fallen; relative to other cities in Sari Pul, the street network in Sar-e Pol has become more connected. Sar-e Pol ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 2nd in 2001-2014.

Sar-e Pol and Afghanistan do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Sar-e Pol fell steadily, while the SNDi of street constructions in Afghanistan followed a zig-zag trend with an overall decrease.

To date, Sar-e Pol is the 13th-most disconnected out of the 40 cities in Afghanistan. Its position in the ranks since 1975 has fallen; relative to other cities in Afghanistan, the street network in Sar-e Pol has become more connected. Sar-e Pol ranked 8th in 1975, 11th in 1976-1990, 13th in 1991-2000 and 13th in 2001-2014.

As of 2015, Sar-e Pol had a built-up area of 0.75 square kilometers, and a population of 164486 people.

These are some other cities with approximately the same population: