Street-network Sprawl in Zaoyang, 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.

Zaoyang: city in Hubei, 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 Zaoyang, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Zaoyang as of 2014, the overall level of street-network sprawl is 2.19, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.74, 2.2, 0.97 and 2.92. The disconnectivity of new streets constructed in Zaoyang fell, then rose. In 1991-2000, new street layouts were the most connected.

Quantity of street network construction: The street network in Zaoyang spans a total of 159 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 2.92, 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 2.74, 2.26, 2.04 and 2.19. The SNDi of the aggregate street network in fell at first, but Zaoyang has worsened in disconnectivity since 2000.

Zaoyang and Hubei do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Zaoyang was at its lowest in 1991-2000, while the SNDi of street constructions in Hubei peaked in 1976-1990.

How do development practices in Zaoyang fare in comparison to others in Hubei? Most recently in 2001-2014, street construction in Zaoyang was the 30th-most disconnected out of the 80 cities in Hubei. Its position in the ranks since 1975 has fallen; relative to other cities in Hubei, street construction in Zaoyang has become more connected. Zaoyang ranked 11th in 1975, 26th in 1976-1990, 47th in 1991-2000 and 30th in 2001-2014.

Zaoyang and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Zaoyang was at its lowest in 1991-2000, while the SNDi of street constructions in China followed a zig-zag trend with an overall decrease.

How do development practices in Zaoyang fare in comparison to others in China? Most recently in 2001-2014, street construction in Zaoyang was the 397th-most disconnected out of the 1651 cities in China. Its position in the ranks since 1975 has fallen; relative to other cities in China, street construction in Zaoyang has become more connected. Zaoyang ranked 297th in 1975, 574th in 1976-1990, 808th in 1991-2000 and 397th in 2001-2014.

Zaoyang and Hubei do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zaoyang was at its lowest in 1991-2000, while the SNDi of street constructions in Hubei peaked in 1976-1990.

To date, Zaoyang is the 32nd-most disconnected out of the 80 cities in Hubei. Its position in the ranks since 1975 has fallen; relative to other cities in Hubei, the street network in Zaoyang has become more connected. Zaoyang ranked 11th in 1975, 27th in 1976-1990, 33rd in 1991-2000 and 32nd in 2001-2014.

Zaoyang and China do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zaoyang was at its lowest in 1991-2000, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Zaoyang is the 617th-most disconnected out of the 1651 cities in China. Its position in the ranks since 1975 has fallen; relative to other cities in China, the street network in Zaoyang has become more connected. Zaoyang ranked 297th in 1975, 550th in 1976-1990, 649th in 1991-2000 and 617th in 2001-2014.

As of 2015, Zaoyang had a built-up area of 17.3 square kilometers, and a population of 171723 people.

These are some other cities with approximately the same population: