Street-network Sprawl in Huojia, 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.

Huojia: 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 Huojia, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Huojia as of 2014, the overall level of street-network sprawl is -0.26, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.89, -0.57, -0.33 and -0.61. Disconnectivity in street construction in Huojia follows a zig-zag trend. In 2001-2014, street construction was most disconnected, while construction was most connected in 1975.

Quantity of street network construction: The street network in Huojia spans a total of 102 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of -0.61, 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 0.89, 0.11, 0.02 and -0.26. Overall, the SNDi of the aggregate street network has fallen: the street network in Huojia has become more connected.

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

How do development practices in Huojia fare in comparison to others in Henan? Most recently in 2001-2014, street construction in Huojia was the 103rd-most disconnected out of the 118 cities in Henan. Its position in the ranks since 1975 has fallen; relative to other cities in Henan, street construction in Huojia has become more connected. Huojia ranked 31st in 1975, 108th in 1976-1990, 82nd in 1991-2000 and 103rd in 2001-2014.

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

How do development practices in Huojia fare in comparison to others in China? Most recently in 2001-2014, street construction in Huojia was the 1362nd-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 Huojia has become more connected. Huojia ranked 864th in 1975, 1445th in 1976-1990, 1160th in 1991-2000 and 1362nd in 2001-2014.

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

To date, Huojia is the 113th-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 Huojia has become more connected. Huojia ranked 31st in 1975, 88th in 1976-1990, 96th in 1991-2000 and 113th in 2001-2014.

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

To date, Huojia is the 1603rd-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 Huojia has become more connected. Huojia ranked 864th in 1975, 1444th in 1976-1990, 1507th in 1991-2000 and 1603rd in 2001-2014.

As of 2015, Huojia had a built-up area of 14.76 square kilometers, and a population of 78461 people.

These are some other cities with approximately the same population: