Street-network Sprawl in Xiaoxian, 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.

Xiaoxian: city in Anhui, 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 Xiaoxian, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Xiaoxian as of 2014, the overall level of street-network sprawl is 0.07, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are -0.84, 0.33, 0.25 and -0.11. Street construction in Xiaoxian increased in disconnectivity initially but has since improved. The streets constructed in 1976-1990 were the most disconnected.

Quantity of street network construction: The street network in Xiaoxian spans a total of 169 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 0.33, 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 -0.84, 0.11, 0.12 and 0.07. The aggregate street network in Xiaoxian increased in disconnectivity initially,but the trend has turned around after 2000.

Xiaoxian and Anhui do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Xiaoxian peaked in 1976-1990, while the SNDi of street constructions in Anhui fell steadily.

How do development practices in Xiaoxian fare in comparison to others in Anhui? Most recently in 2001-2014, street construction in Xiaoxian was the 55th-most disconnected out of the 65 cities in Anhui. Its position in the ranks since 1975 has fallen; relative to other cities in Anhui, street construction in Xiaoxian has become more connected. Xiaoxian ranked 43rd in 1975, 52nd in 1976-1990, 41st in 1991-2000 and 55th in 2001-2014.

Xiaoxian and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Xiaoxian peaked 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 Xiaoxian fare in comparison to others in China? Most recently in 2001-2014, street construction in Xiaoxian was the 1303rd-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 Xiaoxian has become more connected. Xiaoxian ranked 1249th in 1975, 1280th in 1976-1990, 1025th in 1991-2000 and 1303rd in 2001-2014.

Xiaoxian and Anhui do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Xiaoxian peaked in 1991-2000, while the SNDi of street constructions in Anhui fell steadily.

To date, Xiaoxian is the 60th-most disconnected out of the 65 cities in Anhui. Its position in the ranks since 1975 has fallen; relative to other cities in Anhui, the street network in Xiaoxian has become more connected. Xiaoxian ranked 43rd in 1975, 56th in 1976-1990, 58th in 1991-2000 and 60th in 2001-2014.

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

To date, Xiaoxian is the 1546th-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 Xiaoxian has become more connected. Xiaoxian ranked 1249th in 1975, 1441st in 1976-1990, 1483rd in 1991-2000 and 1546th in 2001-2014.

As of 2015, Xiaoxian had a built-up area of 24.61 square kilometers, and a population of 148784 people.

These are some other cities with approximately the same population: