Street-network Sprawl in Sui, 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.

Sui: city in Henan, 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 Sui, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sui as of 2014, the overall level of street-network sprawl is 1.07, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.36, 1.72, -1.48 and 1.49. Disconnectivity in street construction in Sui follows a zig-zag trend. In 1991-2000, street construction was most disconnected, while construction was most connected in 1976-1990.

Quantity of street network construction: The street network in Sui spans a total of 116 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 1.72, 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 0.36, 1.13, 1.04 and 1.07. Disconnectivity in Sui's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 1976-1990.

Sui and Henan do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Sui followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Henan peaked in 1991-2000.

How do development practices in Sui fare in comparison to others in Henan? Most recently in 2001-2014, street construction in Sui was the 35th-most disconnected out of the 118 cities in Henan. Its position in the ranks since 1975 has risen; relative to other cities in Henan, street construction in Sui has become more disconnected. Sui ranked 43rd in 1975, 25th in 1976-1990, 102nd in 1991-2000 and 35th in 2001-2014.

Sui 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 Sui fare in comparison to others in China? Most recently in 2001-2014, street construction in Sui was the 866th-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 Sui has become more disconnected. Sui ranked 1036th in 1975, 774th in 1976-1990, 1287th in 1991-2000 and 866th in 2001-2014.

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

To date, Sui is the 53rd-most disconnected out of the 118 cities in Henan. Its position in the ranks since 1975 has fallen; relative to other cities in Henan, the street network in Sui has become more connected. Sui ranked 43rd in 1975, 46th in 1976-1990, 51st in 1991-2000 and 53rd in 2001-2014.

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

To date, Sui is the 1179th-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 Sui has become more connected. Sui ranked 1036th in 1975, 1073rd in 1976-1990, 1134th in 1991-2000 and 1179th in 2001-2014.

As of 2015, Sui had a built-up area of 12.66 square kilometers, and a population of 78953 people.

These are some other cities with approximately the same population: