Street-network Sprawl in Hechuan, 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.

Hechuan: city in Chongqing, 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 Hechuan, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Hechuan as of 2014, the overall level of street-network sprawl is 1.63, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.71, 1.46, 1.57 and 2.4. The disconnectivity of new streets constructed in Hechuan fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Hechuan spans a total of 259 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 1.46, which is relatively 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 1.71, 1.56, 1.53 and 1.63. The SNDi of the aggregate street network in fell at first, but Hechuan has worsened in disconnectivity since 2000.

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

How do development practices in Hechuan fare in comparison to others in Chongqing? Most recently in 2001-2014, street construction in Hechuan was the 24th-most disconnected out of the 38 cities in Chongqing. Its position in the ranks since 1975 has fallen; relative to other cities in Chongqing, street construction in Hechuan has become more connected. Hechuan ranked 13th in 1975, 21st in 1976-1990, 20th in 1991-2000 and 24th in 2001-2014.

Hechuan and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Hechuan 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 Hechuan fare in comparison to others in China? Most recently in 2001-2014, street construction in Hechuan was the 542nd-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 Hechuan has become more disconnected. Hechuan ranked 582nd in 1975, 890th in 1976-1990, 614th in 1991-2000 and 542nd in 2001-2014.

Hechuan and Chongqing do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Hechuan was at its lowest in 1991-2000, while the SNDi of street constructions in Chongqing followed a zig-zag trend with an overall increase.

To date, Hechuan is the 29th-most disconnected out of the 38 cities in Chongqing. Its position in the ranks since 1975 has fallen; relative to other cities in Chongqing, the street network in Hechuan has become more connected. Hechuan ranked 13th in 1975, 22nd in 1976-1990, 25th in 1991-2000 and 29th in 2001-2014.

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

To date, Hechuan is the 889th-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 Hechuan has become more connected. Hechuan ranked 582nd in 1975, 860th in 1976-1990, 883rd in 1991-2000 and 889th in 2001-2014.

As of 2015, Hechuan had a built-up area of 11.6 square kilometers, and a population of 342268 people.

These are some other cities with approximately the same population: