Street-network Sprawl in Yidu, 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.

Yidu: city in Hubei, 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 Yidu, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Yidu as of 2014, the overall level of street-network sprawl is -0.04, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.59, -0.55, -0.36 and 0.35. The disconnectivity of new streets constructed in Yidu fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Yidu spans a total of 141 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 0.35, 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 0.59, -0.28, -0.27 and -0.04. The SNDi of the aggregate street network in fell at first, but Yidu has worsened in disconnectivity since 1990.

Yidu and Hubei do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Yidu was at its lowest in 1976-1990, while the SNDi of street constructions in Hubei peaked in 1976-1990.

How do development practices in Yidu fare in comparison to others in Hubei? Most recently in 2001-2014, street construction in Yidu was the 61st-most disconnected out of the 80 cities in Hubei. Its position in the ranks since 1975 has fallen; relative to other cities in Hubei, street construction in Yidu has become more connected. Yidu ranked 45th in 1975, 71st in 1976-1990, 57th in 1991-2000 and 61st in 2001-2014.

Yidu and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Yidu was at its lowest 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 Yidu fare in comparison to others in China? Most recently in 2001-2014, street construction in Yidu was the 1213th-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 Yidu has become more connected. Yidu ranked 962nd in 1975, 1444th in 1976-1990, 1165th in 1991-2000 and 1213th in 2001-2014.

Yidu and Hubei do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Yidu was at its lowest in 1976-1990, while the SNDi of street constructions in Hubei peaked in 1976-1990.

To date, Yidu is the 77th-most disconnected out of the 80 cities in Hubei. Its position in the ranks since 1975 has fallen; relative to other cities in Hubei, the street network in Yidu has become more connected. Yidu ranked 45th in 1975, 74th in 1976-1990, 77th in 1991-2000 and 77th in 2001-2014.

Yidu and China do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Yidu was at its lowest in 1976-1990, while the SNDi of street constructions in China peaked in 1976-1990.

To date, Yidu is the 1565th-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 Yidu has become more connected. Yidu ranked 962nd in 1975, 1522nd in 1976-1990, 1563rd in 1991-2000 and 1565th in 2001-2014.

As of 2015, Yidu had a built-up area of 11.98 square kilometers, and a population of 103641 people.

These are some other cities with approximately the same population: