Street-network Sprawl in Tongliao, China

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.

Tongliao: city in Nei Mongol, China

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 Tongliao, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Tongliao as of 2014, the overall level of street-network sprawl is 2.01, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are -0.02, 3.1, 0.39 and 2.58. Disconnectivity in street construction in Tongliao follows a zig-zag trend. In 1975, street construction was most disconnected, while construction was most connected in 1976-1990.

Quantity of street network construction: The street network in Tongliao spans a total of 426 kilometers. The period with the greatest volume of street construction was 2001-2014. These roads have an SNDi of 2.58, which is in the 40th to 60th percentile of disconnectedness.

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 -0.02, 1.7, 1.62 and 2.01. Disconnectivity in Tongliao's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 2001-2014.

Tongliao and Nei Mongol do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Tongliao followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Nei Mongol followed a zig-zag trend with an overall decrease.

How do development practices in Tongliao fare in comparison to others in Nei Mongol? Most recently in 2001-2014, street construction in Tongliao was the 20th-most disconnected out of the 45 cities in Nei Mongol. Its position in the ranks since 1975 has risen; relative to other cities in Nei Mongol, street construction in Tongliao has become more disconnected. Tongliao ranked 27th in 1975, 15th in 1976-1990, 34th in 1991-2000 and 20th in 2001-2014.

Tongliao and China follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these followed a zig-zag trend with an overall increase.

How do development practices in Tongliao fare in comparison to others in China? Most recently in 2001-2014, street construction in Tongliao was the 490th-most disconnected out of the 1651 cities in China. Its position in the ranks since 1975 has risen; relative to other cities in China, street construction in Tongliao has become more disconnected. Tongliao ranked 1120th in 1975, 284th in 1976-1990, 986th in 1991-2000 and 490th in 2001-2014.

Tongliao and Nei Mongol do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Tongliao followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Nei Mongol fell steadily.

To date, Tongliao is the 33rd-most disconnected out of the 45 cities in Nei Mongol. Its position in the ranks since 1975 has fallen; relative to other cities in Nei Mongol, the street network in Tongliao has become more connected. Tongliao ranked 27th in 1975, 31st in 1976-1990, 34th in 1991-2000 and 33rd in 2001-2014.

Tongliao and China do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Tongliao followed a zig-zag trend with an overall increase, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Tongliao is the 695th-most disconnected out of the 1651 cities in China. Its position in the ranks since 1975 has risen; relative to other cities in China, the street network in Tongliao has become more disconnected. Tongliao ranked 1120th in 1975, 781st in 1976-1990, 842nd in 1991-2000 and 695th in 2001-2014.

As of 2015, Tongliao had a built-up area of 49.27 square kilometers, and a population of 527049 people.

These are some other cities with approximately the same population: