Street-network Sprawl in Sirjan, 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.

Sirjan: city in Kerman, 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 Sirjan, Iran on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sirjan as of 2014, the overall level of street-network sprawl is 1.07, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.21, 0.52, 1.14 and 1.39. In each period, new street development in Sirjan steadily grows more disconnected than in the last. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.31 points, but between 1991-2000 and 2001-2014, it rose by just 0.25.

Quantity of street network construction: The street network in Sirjan spans a total of 598 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 1.39, 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 0.21, 0.5, 0.78 and 1.07. Overall, the SNDi of the aggregate street network has risen: the street network in Sirjan 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 0.29.

Sirjan and Kerman do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Sirjan rose steadily, while the SNDi of street constructions in Kerman was at its lowest in 1991-2000.

How do development practices in Sirjan fare in comparison to others in Kerman? Most recently in 2001-2014, street construction in Sirjan was the 5th-most disconnected out of the 9 cities in Kerman. Its position in the ranks since 1975 has risen; relative to other cities in Kerman, street construction in Sirjan has become more disconnected. Sirjan ranked 8th in 1975, 8th in 1976-1990, 4th in 1991-2000 and 5th in 2001-2014.

Sirjan and Iran do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Sirjan rose steadily, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

How do development practices in Sirjan fare in comparison to others in Iran? Most recently in 2001-2014, street construction in Sirjan was the 155th-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 Sirjan has become more connected. Sirjan ranked 128th in 1975, 160th in 1976-1990, 127th in 1991-2000 and 155th in 2001-2014.

Sirjan and Kerman do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Sirjan rose steadily, while the SNDi of street constructions in Kerman fell steadily.

To date, Sirjan is the 8th-most disconnected out of the 9 cities in Kerman. Its position in the ranks since 1975 has not changed. Sirjan ranked 8th in 1975, 9th in 1976-1990, 8th in 1991-2000 and 8th in 2001-2014.

Sirjan and Iran do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Sirjan rose steadily, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

To date, Sirjan is the 162nd-most disconnected out of the 181 cities in Iran. Its position in the ranks since 1975 has fallen; relative to other cities in Iran, the street network in Sirjan has become more connected. Sirjan ranked 128th in 1975, 162nd in 1976-1990, 158th in 1991-2000 and 162nd in 2001-2014.

As of 2015, Sirjan had a built-up area of 20.45 square kilometers, and a population of 216009 people.

These are some other cities with approximately the same population: