Street-network Sprawl in Luzhou, 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.

Luzhou: city in Sichuan, 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 Luzhou, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Luzhou as of 2014, the overall level of street-network sprawl is 1.54, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.11, 1.62, 1.03 and 1.54. The disconnectivity of new streets constructed in Luzhou fell, then rose. In 1991-2000, new street layouts were the most connected.

Quantity of street network construction: The street network in Luzhou spans a total of 282 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 1.54, 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 2.11, 1.97, 1.62 and 1.54. Overall, the SNDi of the aggregate street network has fallen: the street network in Luzhou has become more connected.

Luzhou and Sichuan follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these was at its lowest in 1991-2000.

How do development practices in Luzhou fare in comparison to others in Sichuan? Most recently in 2001-2014, street construction in Luzhou was the 60th-most disconnected out of the 102 cities in Sichuan. Its position in the ranks since 1975 has fallen; relative to other cities in Sichuan, street construction in Luzhou has become more connected. Luzhou ranked 43rd in 1975, 49th in 1976-1990, 47th in 1991-2000 and 60th in 2001-2014.

Luzhou and China do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Luzhou was at its lowest in 1991-2000, while the SNDi of street constructions in China followed a zig-zag trend with an overall decrease.

How do development practices in Luzhou fare in comparison to others in China? Most recently in 2001-2014, street construction in Luzhou was the 842nd-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 Luzhou has become more connected. Luzhou ranked 467th in 1975, 816th in 1976-1990, 776th in 1991-2000 and 842nd in 2001-2014.

Luzhou and Sichuan do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Luzhou fell steadily, while the SNDi of street constructions in Sichuan was at its lowest in 1991-2000.

To date, Luzhou is the 70th-most disconnected out of the 102 cities in Sichuan. Its position in the ranks since 1975 has fallen; relative to other cities in Sichuan, the street network in Luzhou has become more connected. Luzhou ranked 43rd in 1975, 54th in 1976-1990, 56th in 1991-2000 and 70th in 2001-2014.

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

To date, Luzhou is the 940th-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 Luzhou has become more connected. Luzhou ranked 467th in 1975, 667th in 1976-1990, 841st in 1991-2000 and 940th in 2001-2014.

As of 2015, Luzhou had a built-up area of 16.36 square kilometers, and a population of 519824 people.

These are some other cities with approximately the same population: