Street-network Sprawl in Trà Vinh, 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.

Trà Vinh: 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 Trà Vinh, Vietnam on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Trà Vinh as of 2014, the overall level of street-network sprawl is 1.56, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.65, 1.33, 1.6 and 2.42. The disconnectivity of new streets constructed in Trà Vinh fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Trà Vinh spans a total of 1123 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 1.33, 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 1.65, 1.36, 1.36 and 1.56. The SNDi of the aggregate street network in fell at first, but Trà Vinh has worsened in disconnectivity since 2000.

The level of street-network sprawl in new development in Trà Vinh was at its lowest in 1976-1990. To get a sense of how street development has changed in Trà Vinh, we can consider one of its most populous cities: Trà Vinh City. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Trà Vinh City followed a zig-zag trend with an overall increase.

How do development practices in Trà Vinh fare in comparison to others in Vietnam? Most recently in 2001-2014, street construction in Trà Vinh was the 50th-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 Trà Vinh has become more connected. Trà Vinh ranked 41st in 1975, 52nd in 1976-1990, 57th in 1991-2000 and 50th in 2001-2014.

As of 2014, the city with the most disconnected street network in Trà Vinh is Trà Vinh City with an SNDi of 0.91, which is relatively well-connected. Conversely, the most connected city is Trà Vinh City with an SNDi of 0.91, which is relatively well-connected. See trends for these cities: Trà Vinh City, Trà Vinh City

The level of street-network sprawl in the aggregate network in Trà Vinh was at its lowest in 1991-2000. To get a sense of how the aggregate street network has changed in Trà Vinh, we can consider one of its most populous cities: Trà Vinh City. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Trà Vinh City was at its lowest in 1976-1990.

To date, Trà Vinh is the 57th-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 Trà Vinh has become more connected. Trà Vinh ranked 41st in 1975, 56th in 1976-1990, 58th in 1991-2000 and 57th in 2001-2014.