Street-network Sprawl in Zhenlai, 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.

Zhenlai: city in Jilin, 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 Zhenlai, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Zhenlai as of 2014, the overall level of street-network sprawl is 1.09, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are -0.52, 1.25, 1.47 and 5.6. In each period, new street development in Zhenlai steadily grows more disconnected than in the last.

Quantity of street network construction: The street network in Zhenlai spans a total of 74 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 1.25, 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 -0.52, 0.55, 0.95 and 1.09. Overall, the SNDi of the aggregate street network has risen: the street network in Zhenlai has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 1.07 points, but between 1991-2000 and 2001-2014, it rose by just 0.14.

Zhenlai and Jilin do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Zhenlai rose steadily, while the SNDi of street constructions in Jilin followed a zig-zag trend with an overall decrease.

How do development practices in Zhenlai fare in comparison to others in Jilin? Most recently in 2001-2014, street construction in Zhenlai was the 5th-most disconnected out of the 42 cities in Jilin. Its position in the ranks since 1975 has risen; relative to other cities in Jilin, street construction in Zhenlai has become more disconnected. Zhenlai ranked 41st in 1975, 22nd in 1976-1990, 3rd in 1991-2000 and 5th in 2001-2014.

Zhenlai and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Zhenlai rose steadily, while the SNDi of street constructions in China followed a zig-zag trend with an overall decrease.

How do development practices in Zhenlai fare in comparison to others in China? Most recently in 2001-2014, street construction in Zhenlai was the 68th-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 Zhenlai has become more disconnected. Zhenlai ranked 1209th in 1975, 978th in 1976-1990, 638th in 1991-2000 and 68th in 2001-2014.

Zhenlai and Jilin do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zhenlai rose steadily, while the SNDi of street constructions in Jilin followed a zig-zag trend with an overall decrease.

To date, Zhenlai is the 25th-most disconnected out of the 42 cities in Jilin. Its position in the ranks since 1975 has risen; relative to other cities in Jilin, the street network in Zhenlai has become more disconnected. Zhenlai ranked 41st in 1975, 33rd in 1976-1990, 26th in 1991-2000 and 25th in 2001-2014.

Zhenlai and China do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Zhenlai rose steadily, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Zhenlai is the 1169th-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 Zhenlai has become more disconnected. Zhenlai ranked 1209th in 1975, 1326th in 1976-1990, 1173rd in 1991-2000 and 1169th in 2001-2014.

As of 2015, Zhenlai had a built-up area of 9.37 square kilometers, and a population of 70422 people.

These are some other cities with approximately the same population: