Street-network Sprawl in Absheron, Azerbaijan

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.

Absheron: region in Azerbaijan

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 Absheron, Azerbaijan on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Absheron as of 2014, the overall level of street-network sprawl is 4.7, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 4.69, 4.69, 4.91 and 4.64. Street construction in Absheron 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 Absheron spans a total of 9891 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 4.69, which is highly disconnected.

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 4.69, 4.69, 4.71 and 4.7. Disconnectivity in Absheron's street network follows a zig-zag trend. In 1976-1990, the region was most disconnected; while it was most connected in 1991-2000.

The level of street-network sprawl in new development in Absheron peaked in 1991-2000. To get a sense of how street development has changed in Absheron, we can consider two of its most populous cities: Baku and Sumgayit. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Baku rose steadily. The level of street-network sprawl in new development in Sumgayit followed a zig-zag trend with an overall increase.

How do development practices in Absheron fare in comparison to others in Azerbaijan? Most recently in 2001-2014, street construction in Absheron was the 2nd-most disconnected out of the 8 regions in Azerbaijan. Its position in the ranks since 1975 has risen; relative to other regions in Azerbaijan, street construction in Absheron has become more disconnected. Absheron ranked 5th in 1975, 3rd in 1976-1990, 2nd in 1991-2000 and 2nd in 2001-2014.

As of 2014, the city with the most disconnected street network in Absheron is Sumgayit with an SNDi of 4.86, which is highly disconnected. Conversely, the most connected city is Baku with an SNDi of 4.56, which is highly disconnected. See trends for these cities: Baku, Sumgayit

The level of street-network sprawl in the aggregate network in Absheron followed a zig-zag trend with an overall increase. To get a sense of how the aggregate street network has changed in Absheron, we can consider two of its most populous cities: Baku and Sumgayit. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Baku rose steadily. The level of street-network sprawl in the aggregate network in Sumgayit peaked in 1976-1990.

To date, Absheron is the 3rd-most disconnected out of the 8 regions in Azerbaijan. Its position in the ranks since 1975 has risen; relative to other regions in Azerbaijan, the street network in Absheron has become more disconnected. Absheron ranked 5th in 1975, 3rd in 1976-1990, 2nd in 1991-2000 and 3rd in 2001-2014.