Street-network Sprawl in Adiyaman, Turkey

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.

Adiyaman: region in Turkey

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 Adiyaman, Turkey on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Adiyaman as of 2014, the overall level of street-network sprawl is 2.03, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.1, 1.8, 1.69 and 2.99. The disconnectivity of new streets constructed in Adiyaman fell, then rose. In 1991-2000, new street layouts were the most connected.

Quantity of street network construction: The street network in Adiyaman spans a total of 3852 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 1.8, 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 2.1, 1.87, 1.82 and 2.03. The SNDi of the aggregate street network in fell at first, but Adiyaman has worsened in disconnectivity since 2000.

The level of street-network sprawl in new development in Adiyaman was at its lowest in 1991-2000. To get a sense of how street development has changed in Adiyaman, we can consider two of its most populous cities: Adiyaman and Kahta. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Adiyaman rose steadily. The level of street-network sprawl in new development in Kahta followed a zig-zag trend.

How do development practices in Adiyaman fare in comparison to others in Turkey? Most recently in 2001-2014, street construction in Adiyaman was the 45th-most disconnected out of the 71 regions in Turkey. Its position in the ranks since 1975 has fallen; relative to other regions in Turkey, street construction in Adiyaman has become more connected. Adiyaman ranked 40th in 1975, 44th in 1976-1990, 61st in 1991-2000 and 45th in 2001-2014.

As of 2014, the city with the most disconnected street network in Adiyaman is Adiyaman with an SNDi of 0.34, which is very well-connected. Conversely, the most connected city is Kahta with an SNDi of 0.16, which is very well-connected. See trends for these cities: Kahta, Adiyaman

The level of street-network sprawl in the aggregate network in Adiyaman was at its lowest in 1991-2000. To get a sense of how the aggregate street network has changed in Adiyaman, we can consider two of its most populous cities: Adiyaman and Kahta. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Adiyaman rose steadily. The level of street-network sprawl in the aggregate network in Kahta followed a zig-zag trend.

To date, Adiyaman is the 42nd-most disconnected out of the 71 regions in Turkey. Its position in the ranks since 1975 has fallen; relative to other regions in Turkey, the street network in Adiyaman has become more connected. Adiyaman ranked 40th in 1975, 39th in 1976-1990, 44th in 1991-2000 and 42nd in 2001-2014.