Street-network Sprawl in Liaoning, 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.

Liaoning: region in 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 Liaoning, China on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Liaoning as of 2014, the overall level of street-network sprawl is 2.04, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.68, 2.73, 2.44 and 2.1. Street construction in Liaoning 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 Liaoning spans a total of 75069 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 2.73, which is in the 40th to 60th percentile of disconnectedness.

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 1.68, 2.03, 2.05 and 2.04. The aggregate street network in Liaoning increased in disconnectivity initially,but the trend has turned around after 2000.

The level of street-network sprawl in new development in Liaoning peaked in 1976-1990. To get a sense of how street development has changed in Liaoning, we can consider three of its most populous cities: Shenyang, Dalian and Anshan. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Shenyang peaked in 1991-2000. The level of street-network sprawl in new development in Dalian followed a zig-zag trend with an overall increase. The level of street-network sprawl in new development in Anshan peaked in 1991-2000.

How do development practices in Liaoning fare in comparison to others in China? Most recently in 2001-2014, street construction in Liaoning was the 30th-most disconnected out of the 34 regions in China. Its position in the ranks since 1975 has fallen; relative to other regions in China, street construction in Liaoning has become more connected. Liaoning ranked 29th in 1975, 25th in 1976-1990, 26th in 1991-2000 and 30th in 2001-2014.

As of 2014, the city with the most disconnected street network in Liaoning is Yixian with an SNDi of 3.65, which is highly disconnected. Conversely, the most connected city is Gushan with an SNDi of -1.55, which is very well-connected. See trends for these cities: Gushan, Yixian

The level of street-network sprawl in the aggregate network in Liaoning peaked in 1991-2000. To get a sense of how the aggregate street network has changed in Liaoning, we can consider three of its most populous cities: Shenyang, Dalian and Anshan. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Shenyang rose steadily. The level of street-network sprawl in the aggregate network in Dalian rose steadily. The level of street-network sprawl in the aggregate network in Anshan rose steadily.

To date, Liaoning is the 32nd-most disconnected out of the 34 regions in China. Its position in the ranks since 1975 has fallen; relative to other regions in China, the street network in Liaoning has become more connected. Liaoning ranked 29th in 1975, 31st in 1976-1990, 31st in 1991-2000 and 32nd in 2001-2014.