Street-network Sprawl in Sabzevar, 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.

Sabzevar: city in Razavi Khorasan, 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 Sabzevar, Iran on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sabzevar as of 2014, the overall level of street-network sprawl is 1.88, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.21, 1.7, 1.5 and 1.89. The disconnectivity of new streets constructed in Sabzevar fell, then rose. In 1991-2000, new street layouts were the most connected.

Quantity of street network construction: The street network in Sabzevar spans a total of 442 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 1.89, 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 2.21, 1.83, 1.68 and 1.88. The SNDi of the aggregate street network in fell at first, but Sabzevar has worsened in disconnectivity since 2000.

Sabzevar and Razavi Khorasan do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Sabzevar was at its lowest in 1991-2000, while the SNDi of street constructions in Razavi Khorasan followed a zig-zag trend with an overall increase.

How do development practices in Sabzevar fare in comparison to others in Razavi Khorasan? Most recently in 2001-2014, street construction in Sabzevar was the 7th-most disconnected out of the 14 cities in Razavi Khorasan. Its position in the ranks since 1975 has fallen; relative to other cities in Razavi Khorasan, street construction in Sabzevar has become more connected. Sabzevar ranked 6th in 1975, 8th in 1976-1990, 11th in 1991-2000 and 7th in 2001-2014.

Sabzevar and Iran do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Sabzevar was at its lowest in 1991-2000, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

How do development practices in Sabzevar fare in comparison to others in Iran? Most recently in 2001-2014, street construction in Sabzevar was the 133rd-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 Sabzevar has become more connected. Sabzevar ranked 70th in 1975, 83rd in 1976-1990, 117th in 1991-2000 and 133rd in 2001-2014.

Sabzevar and Razavi Khorasan do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Sabzevar was at its lowest in 1991-2000, while the SNDi of street constructions in Razavi Khorasan was at its lowest in 1976-1990.

To date, Sabzevar is the 6th-most disconnected out of the 14 cities in Razavi Khorasan. Its position in the ranks since 1975 has not changed. Sabzevar ranked 6th in 1975, 8th in 1976-1990, 10th in 1991-2000 and 6th in 2001-2014.

Sabzevar and Iran do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Sabzevar was at its lowest in 1991-2000, while the SNDi of street constructions in Iran was at its lowest in 1976-1990.

To date, Sabzevar is the 99th-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 Sabzevar has become more connected. Sabzevar ranked 70th in 1975, 80th in 1976-1990, 100th in 1991-2000 and 99th in 2001-2014.

As of 2015, Sabzevar had a built-up area of 14.53 square kilometers, and a population of 177694 people.

These are some other cities with approximately the same population: