Street-network Sprawl in Yongnian, 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.

Yongnian: city in Hebei, 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 Yongnian, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Yongnian as of 2014, the overall level of street-network sprawl is 1.49, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.46, 1.69, 1.37 and 0.91. Street construction in Yongnian 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 Yongnian spans a total of 519 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 1.69, 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 1.46, 1.61, 1.6 and 1.49. The aggregate street network in Yongnian increased in disconnectivity initially,but the trend has turned around after 1990.

Yongnian and Hebei do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Yongnian peaked in 1976-1990, while the SNDi of street constructions in Hebei followed a zig-zag trend with an overall decrease.

How do development practices in Yongnian fare in comparison to others in Hebei? Most recently in 2001-2014, street construction in Yongnian was the 71st-most disconnected out of the 99 cities in Hebei. Its position in the ranks since 1975 has fallen; relative to other cities in Hebei, street construction in Yongnian has become more connected. Yongnian ranked 48th in 1975, 55th in 1976-1990, 35th in 1991-2000 and 71st in 2001-2014.

Yongnian and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Yongnian 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 Yongnian fare in comparison to others in China? Most recently in 2001-2014, street construction in Yongnian was the 1037th-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 Yongnian has become more connected. Yongnian ranked 670th in 1975, 782nd in 1976-1990, 667th in 1991-2000 and 1037th in 2001-2014.

Yongnian and Hebei follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these peaked in 1976-1990.

To date, Yongnian is the 57th-most disconnected out of the 99 cities in Hebei. Its position in the ranks since 1975 has fallen; relative to other cities in Hebei, the street network in Yongnian has become more connected. Yongnian ranked 48th in 1975, 56th in 1976-1990, 52nd in 1991-2000 and 57th in 2001-2014.

Yongnian and China follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these peaked in 1976-1990.

To date, Yongnian is the 960th-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 Yongnian has become more connected. Yongnian ranked 670th in 1975, 830th in 1976-1990, 850th in 1991-2000 and 960th in 2001-2014.

As of 2015, Yongnian had a built-up area of 67.92 square kilometers, and a population of 357199 people.

These are some other cities with approximately the same population: