Street-network Sprawl in Gia Lai, Vietnam

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.

Gia Lai: region in Vietnam

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 Gia Lai, Vietnam on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Gia Lai as of 2014, the overall level of street-network sprawl is 2.75, which is in the 40th to 60th percentile of disconnectedness.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.81, 2.39, 2.67 and 3.26. In each period, new street development in Gia Lai steadily grows more disconnected than in the last.

Quantity of street network construction: The street network in Gia Lai spans a total of 5348 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 3.26, 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 1.81, 2.03, 2.39 and 2.75. Overall, the SNDi of the aggregate street network has risen: the street network in Gia Lai has become more disconnected.

The level of street-network sprawl in new development in Gia Lai rose steadily. To get a sense of how street development has changed in Gia Lai, we can consider two of its most populous cities: Pleiku and An Khê. Out of the two cities, Pleiku does not follow the same trend as the region. The level of street-network sprawl in new development in Pleiku was at its lowest in 1976-1990.

How do development practices in Gia Lai fare in comparison to others in Vietnam? Most recently in 2001-2014, street construction in Gia Lai was the 45th-most disconnected out of the 59 regions in Vietnam. Its position in the ranks since 1975 has fallen; relative to other regions in Vietnam, street construction in Gia Lai has become more connected. Gia Lai ranked 40th in 1975, 40th in 1976-1990, 42nd in 1991-2000 and 45th in 2001-2014.

As of 2014, the city with the most disconnected street network in Gia Lai is Pleiku with an SNDi of 1.68, which is relatively well-connected. Conversely, the most connected city is An Khê with an SNDi of 0.84, which is relatively well-connected. See trends for these cities: An Khê, Pleiku

The level of street-network sprawl in the aggregate network in Gia Lai rose steadily. To get a sense of how the aggregate street network has changed in Gia Lai, we can consider two of its most populous cities: Pleiku and An Khê. Out of the two cities, Pleiku does not follow the same trend as the region. The level of street-network sprawl in the aggregate network in Pleiku was at its lowest in 1976-1990.

To date, Gia Lai is the 46th-most disconnected out of the 59 regions in Vietnam. Its position in the ranks since 1975 has fallen; relative to other regions in Vietnam, the street network in Gia Lai has become more connected. Gia Lai ranked 40th in 1975, 52nd in 1976-1990, 47th in 1991-2000 and 46th in 2001-2014.