Street-network Sprawl in Sardasht, 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.

Sardasht: city in West Azarbaijan, 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 Sardasht, Iran on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sardasht as of 2014, the overall level of street-network sprawl is 0.74, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.53, 0.33, 1.14 and 1.01. Disconnectivity in street construction in Sardasht follows a zig-zag trend. In 1976-1990, street construction was most disconnected, while construction was most connected in 1991-2000.

Quantity of street network construction: The street network in Sardasht spans a total of 108 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 1.01, 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 0.53, 0.34, 0.45 and 0.74. The SNDi of the aggregate street network in fell at first, but Sardasht has worsened in disconnectivity since 1990.

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

How do development practices in Sardasht fare in comparison to others in West Azarbaijan? Most recently in 2001-2014, street construction in Sardasht was the 11th-most disconnected out of the 11 cities in West Azarbaijan. Its position in the ranks since 1975 has fallen; relative to other cities in West Azarbaijan, street construction in Sardasht has become more connected. Sardasht ranked 7th in 1975, 10th in 1976-1990, 8th in 1991-2000 and 11th in 2001-2014.

Sardasht and Iran do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Sardasht 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 Sardasht fare in comparison to others in Iran? Most recently in 2001-2014, street construction in Sardasht was the 167th-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 Sardasht has become more connected. Sardasht ranked 124th in 1975, 165th in 1976-1990, 126th in 1991-2000 and 167th in 2001-2014.

Sardasht and West Azarbaijan follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these was at its lowest in 1976-1990.

To date, Sardasht is the 10th-most disconnected out of the 11 cities in West Azarbaijan. Its position in the ranks since 1975 has fallen; relative to other cities in West Azarbaijan, the street network in Sardasht has become more connected. Sardasht ranked 7th in 1975, 10th in 1976-1990, 9th in 1991-2000 and 10th in 2001-2014.

Sardasht and Iran follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these was at its lowest in 1976-1990.

To date, Sardasht is the 174th-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 Sardasht has become more connected. Sardasht ranked 124th in 1975, 166th in 1976-1990, 170th in 1991-2000 and 174th in 2001-2014.

As of 2015, Sardasht had a built-up area of 1.99 square kilometers, and a population of 57871 people.

These are some other cities with approximately the same population: