Street-network Sprawl in Dayr Az Zawr, Syria

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.

Dayr Az Zawr: region in Syria

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 Dayr Az Zawr, Syria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Dayr Az Zawr as of 2014, the overall level of street-network sprawl is 1.87, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.72, 2.22, 2.48 and 2.43. Street construction in Dayr Az Zawr increased in disconnectivity initially but has since improved. The streets constructed in 1991-2000 were the most disconnected.

Quantity of street network construction: The street network in Dayr Az Zawr spans a total of 3340 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 1.72, 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 1.72, 1.82, 1.81 and 1.87. Disconnectivity in Dayr Az Zawr's street network follows a zig-zag trend. In 1975, the region was most disconnected; while it was most connected in 2001-2014.

The level of street-network sprawl in new development in Dayr Az Zawr peaked in 1991-2000. To get a sense of how street development has changed in Dayr Az Zawr, we can consider three of its most populous cities: Deir Ez Zor, Al Qurayya and Abu Kamal. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Deir Ez Zor followed a zig-zag trend. The level of street-network sprawl in new development in Al Qurayya was at its lowest in 1991-2000. The level of street-network sprawl in new development in Abu Kamal followed a zig-zag trend with an overall increase.

How do development practices in Dayr Az Zawr fare in comparison to others in Syria? Most recently in 2001-2014, street construction in Dayr Az Zawr was the 10th-most disconnected out of the 12 regions in Syria. Its position in the ranks since 1975 has fallen; relative to other regions in Syria, street construction in Dayr Az Zawr has become more connected. Dayr Az Zawr ranked 4th in 1975, 5th in 1976-1990, 6th in 1991-2000 and 10th in 2001-2014.

As of 2014, the city with the most disconnected street network in Dayr Az Zawr is Al Qurayya with an SNDi of 2.79, which is in the 40th to 60th percentile of disconnectedness. Conversely, the most connected city is Abu Kamal with an SNDi of -0.19, which is very well-connected. See trends for these cities: Abu Kamal, Al Qurayya

The level of street-network sprawl in the aggregate network in Dayr Az Zawr followed a zig-zag trend with an overall increase. To get a sense of how the aggregate street network has changed in Dayr Az Zawr, we can consider three of its most populous cities: Deir Ez Zor, Al Qurayya and Abu Kamal. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Deir Ez Zor rose steadily. The level of street-network sprawl in the aggregate network in Al Qurayya was at its lowest in 1991-2000. The level of street-network sprawl in the aggregate network in Abu Kamal was at its lowest in 1976-1990.

To date, Dayr Az Zawr is the 6th-most disconnected out of the 12 regions in Syria. Its position in the ranks since 1975 has fallen; relative to other regions in Syria, the street network in Dayr Az Zawr has become more connected. Dayr Az Zawr ranked 4th in 1975, 5th in 1976-1990, 5th in 1991-2000 and 6th in 2001-2014.