Street-network Sprawl in Chengcheng, 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.

Chengcheng: city in Shaanxi, 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 Chengcheng, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Chengcheng as of 2014, the overall level of street-network sprawl is 0.35, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.33, -0.16, 0.37 and 1.24. The disconnectivity of new streets constructed in Chengcheng fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Chengcheng spans a total of 89 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of -0.16, which is very 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 3.33, 0.17, 0.13 and 0.35. The SNDi of the aggregate street network in fell at first, but Chengcheng has worsened in disconnectivity since 2000.

Chengcheng and Shaanxi follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these was at its lowest in 1976-1990.

How do development practices in Chengcheng fare in comparison to others in Shaanxi? Most recently in 2001-2014, street construction in Chengcheng was the 33rd-most disconnected out of the 60 cities in Shaanxi. Its position in the ranks since 1975 has fallen; relative to other cities in Shaanxi, street construction in Chengcheng has become more connected. Chengcheng ranked 8th in 1975, 50th in 1976-1990, 34th in 1991-2000 and 33rd in 2001-2014.

Chengcheng and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Chengcheng was at its lowest in 1976-1990, while the SNDi of street constructions in China followed a zig-zag trend with an overall decrease.

How do development practices in Chengcheng fare in comparison to others in China? Most recently in 2001-2014, street construction in Chengcheng was the 929th-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 Chengcheng has become more connected. Chengcheng ranked 184th in 1975, 1393rd in 1976-1990, 989th in 1991-2000 and 929th in 2001-2014.

Chengcheng and Shaanxi follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these was at its lowest in 1991-2000.

To date, Chengcheng is the 55th-most disconnected out of the 60 cities in Shaanxi. Its position in the ranks since 1975 has fallen; relative to other cities in Shaanxi, the street network in Chengcheng has become more connected. Chengcheng ranked 8th in 1975, 49th in 1976-1990, 52nd in 1991-2000 and 55th in 2001-2014.

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

To date, Chengcheng is the 1461st-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 Chengcheng has become more connected. Chengcheng ranked 184th in 1975, 1427th in 1976-1990, 1480th in 1991-2000 and 1461st in 2001-2014.

As of 2015, Chengcheng had a built-up area of 12.94 square kilometers, and a population of 91308 people.

These are some other cities with approximately the same population: