Street-network Sprawl in Tajikistan

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.

Tajikistan

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 Tajikistan on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Tajikistan as of 2014, the overall level of street-network sprawl is 4.3, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 4.46, 3.8, 4.19 and 4.78. The disconnectivity of new streets constructed in Tajikistan fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Tajikistan spans a total of 16470 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 3.8, 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 4.46, 4.17, 4.16 and 4.3. The SNDi of the aggregate street network in fell at first, but Tajikistan has worsened in disconnectivity since 2000.

The level of street-network sprawl in new development in Tajikistan was at its lowest in 1976-1990. To get a sense of how street development has changed in Tajikistan, we can consider three of its most populous regions: Dushanbe, Leninabad and Khatlon. Out of the three regions, Leninabad and Khatlon do not follow the same trend as the country. The level of street-network sprawl in new development in Leninabad followed a zig-zag trend with an overall decrease. The level of street-network sprawl in new development in Khatlon was at its lowest in 1991-2000.

How do development practices in Tajikistan fare in comparison to others in the world? Most recently in 2001-2014, street construction in Tajikistan was the 60th-most disconnected out of the 155 countries in the world. Its position in the ranks since 1975 has fallen; relative to other countries in the world, street construction in Tajikistan has become more connected. Tajikistan ranked 24th in 1975, 57th in 1976-1990, 73rd in 1991-2000 and 60th in 2001-2014.

The largest city in Tajikistan is Dushanbe, with a population of 1063700 people. Taking into account the entire (i.e. aggregate) street network in Dushanbe as of 2014, the overall level of street-network sprawl is 3.1, which is in the 40th to 60th percentile of disconnectedness. The level of street-network sprawl in new development in Dushanbe followed a zig-zag trend with an overall increase.

As of 2014, the city with the most disconnected street network in Tajikistan is Khorugh with an SNDi of 6.19, which is highly disconnected. Conversely, the most connected city is Shahrinav with an SNDi of 0.39, which is very well-connected. See trends for these cities: Shahrinav, Khorugh

The level of street-network sprawl in the aggregate network in Tajikistan was at its lowest in 1991-2000. To get a sense of how the aggregate street network has changed in Tajikistan, we can consider three of its most populous regions: Dushanbe, Leninabad and Khatlon. Out of the three regions, Dushanbe and Leninabad do not follow the same trend as the country. The level of street-network sprawl in the aggregate network in Dushanbe was at its lowest in 1976-1990. The level of street-network sprawl in the aggregate network in Leninabad fell steadily.

To date, Tajikistan is the 46th-most disconnected out of the 155 countries in the world. Its position in the ranks since 1975 has fallen; relative to other countries in the world, the street network in Tajikistan has become more connected. Tajikistan ranked 24th in 1975, 38th in 1976-1990, 45th in 1991-2000 and 46th in 2001-2014.

The largest city in Tajikistan is Dushanbe, with a population of 1063700 people. Taking into account the entire (i.e. aggregate) street network in Dushanbe as of 2014, the overall level of street-network sprawl is 3.1, which is in the 40th to 60th percentile of disconnectedness. The level of street-network sprawl in the aggregate network in Dushanbe was at its lowest in 1976-1990.