Street-network Sprawl in New Taipei, Taiwan

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.

New Taipei: region in Taiwan

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 New Taipei, Taiwan on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in New Taipei as of 2014, the overall level of street-network sprawl is 1.5, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.92, 2.75, 0.85 and 4.1. Disconnectivity in street construction in New Taipei follows a zig-zag trend. In 1991-2000, street construction was most disconnected, while construction was most connected in 2001-2014.

Quantity of street network construction: The street network in New Taipei spans a total of 4229 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 0.92, 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 0.92, 1.43, 1.43 and 1.5. Overall, the SNDi of the aggregate street network has risen: the street network in New Taipei has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.51 points, but between 1991-2000 and 2001-2014, it rose by just 0.06.

The level of street-network sprawl in new development in New Taipei followed a zig-zag trend with an overall increase. To get a sense of how street development has changed in New Taipei, we can consider one of its most populous cities: Danhai. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Danhai followed a zig-zag trend with an overall increase.

How do development practices in New Taipei fare in comparison to others in Taiwan? Most recently in 2001-2014, street construction in New Taipei was the 1st-most disconnected out of the 5 regions in Taiwan. Its position in the ranks since 1975 has risen; relative to other regions in Taiwan, street construction in New Taipei has become more disconnected. New Taipei ranked 4th in 1975, 1st in 1976-1990, 4th in 1991-2000 and 1st in 2001-2014.

As of 2014, the city with the most disconnected street network in New Taipei is Danhai with an SNDi of 3.24, which is in the 40th to 60th percentile of disconnectedness. Conversely, the most connected city is Danhai with an SNDi of 3.24, which is in the 40th to 60th percentile of disconnectedness. See trends for these cities: Danhai, Danhai

The level of street-network sprawl in the aggregate network in New Taipei rose steadily. To get a sense of how the aggregate street network has changed in New Taipei, we can consider one of its most populous cities: Danhai. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Danhai rose steadily.

To date, New Taipei is the 3rd-most disconnected out of the 5 regions in Taiwan. Its position in the ranks since 1975 has risen; relative to other regions in Taiwan, the street network in New Taipei has become more disconnected. New Taipei ranked 4th in 1975, 3rd in 1976-1990, 3rd in 1991-2000 and 3rd in 2001-2014.