Street-network Sprawl in Zahedan, Iran

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.

Zahedan: city in Sistan and Baluchestan, Iran

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 Zahedan, Iran on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Zahedan as of 2014, the overall level of street-network sprawl is 2.16, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.47, 2.14, 1.98 and 2.25. Disconnectivity in street construction in Zahedan follows a zig-zag trend. In 1975, street construction was most disconnected, while construction was most connected in 2001-2014.

Quantity of street network construction: The street network in Zahedan spans a total of 736 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 2.25, 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 1.47, 2.08, 2.06 and 2.16. Disconnectivity in Zahedan's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 2001-2014.

Zahedan and Sistan and Baluchestan do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Zahedan followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Sistan and Baluchestan followed a zig-zag trend with an overall decrease.

How do development practices in Zahedan fare in comparison to others in Sistan and Baluchestan? Most recently in 2001-2014, street construction in Zahedan was the 3rd-most disconnected out of the 9 cities in Sistan and Baluchestan. Its position in the ranks since 1975 has risen; relative to other cities in Sistan and Baluchestan, street construction in Zahedan has become more disconnected. Zahedan ranked 5th in 1975, 4th in 1976-1990, 2nd in 1991-2000 and 3rd in 2001-2014.

Zahedan and Iran do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Zahedan followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

How do development practices in Zahedan fare in comparison to others in Iran? Most recently in 2001-2014, street construction in Zahedan was the 118th-most disconnected out of the 181 cities in Iran. Its position in the ranks since 1975 has fallen; relative to other cities in Iran, street construction in Zahedan has become more connected. Zahedan ranked 93rd in 1975, 61st in 1976-1990, 99th in 1991-2000 and 118th in 2001-2014.

Zahedan and Sistan and Baluchestan do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zahedan followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Sistan and Baluchestan fell steadily.

To date, Zahedan is the 3rd-most disconnected out of the 9 cities in Sistan and Baluchestan. Its position in the ranks since 1975 has risen; relative to other cities in Sistan and Baluchestan, the street network in Zahedan has become more disconnected. Zahedan ranked 5th in 1975, 3rd in 1976-1990, 3rd in 1991-2000 and 3rd in 2001-2014.

Zahedan and Iran do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zahedan followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

To date, Zahedan is the 85th-most disconnected out of the 181 cities in Iran. Its position in the ranks since 1975 has risen; relative to other cities in Iran, the street network in Zahedan has become more disconnected. Zahedan ranked 93rd in 1975, 61st in 1976-1990, 74th in 1991-2000 and 85th in 2001-2014.

As of 2015, Zahedan had a built-up area of 16.99 square kilometers, and a population of 614275 people.

These are some other cities with approximately the same population: