Street-network Sprawl in Nusa Tenggara Barat, Indonesia

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.

Nusa Tenggara Barat: region in Indonesia

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 Nusa Tenggara Barat, Indonesia on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Nusa Tenggara Barat as of 2014, the overall level of street-network sprawl is 4.66, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 4.29, 3.6, 5.24 and 5.68. The disconnectivity of new streets constructed in Nusa Tenggara Barat fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Nusa Tenggara Barat spans a total of 15365 kilometers. The period with the greatest volume of street construction was 2001-2014. These roads have an SNDi of 5.68, which is highly disconnected.

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 4.29, 4.21, 4.4 and 4.66. The SNDi of the aggregate street network in fell at first, but Nusa Tenggara Barat has worsened in disconnectivity since 1990.

The level of street-network sprawl in new development in Nusa Tenggara Barat was at its lowest in 1976-1990. To get a sense of how street development has changed in Nusa Tenggara Barat, we can consider three of its most populous cities: Mataram, Selong and Kecamatan Wanasaba. Out of the three cities, Mataram and Selong do not follow the same trend as the region. The level of street-network sprawl in new development in Mataram followed a zig-zag trend with an overall increase. The level of street-network sprawl in new development in Selong followed a zig-zag trend with an overall increase.

How do development practices in Nusa Tenggara Barat fare in comparison to others in Indonesia? Most recently in 2001-2014, street construction in Nusa Tenggara Barat was the 22nd-most disconnected out of the 32 regions in Indonesia. Its position in the ranks since 1975 has fallen; relative to other regions in Indonesia, street construction in Nusa Tenggara Barat has become more connected. Nusa Tenggara Barat ranked 20th in 1975, 21st in 1976-1990, 21st in 1991-2000 and 22nd in 2001-2014.

As of 2014, the city with the most disconnected street network in Nusa Tenggara Barat is Mataram with an SNDi of 4.46, which is highly disconnected. Conversely, the most connected city is Kecamatan Bolo with an SNDi of 0.76, which is relatively well-connected. See trends for these cities: Kecamatan Bolo, Mataram

The level of street-network sprawl in the aggregate network in Nusa Tenggara Barat was at its lowest in 1976-1990. To get a sense of how the aggregate street network has changed in Nusa Tenggara Barat, we can consider three of its most populous cities: Mataram, Selong and Kecamatan Wanasaba. Out of the three cities, Mataram and Selong do not follow the same trend as the region. The level of street-network sprawl in the aggregate network in Mataram rose steadily. The level of street-network sprawl in the aggregate network in Selong rose steadily.

To date, Nusa Tenggara Barat is the 24th-most disconnected out of the 32 regions in Indonesia. Its position in the ranks since 1975 has fallen; relative to other regions in Indonesia, the street network in Nusa Tenggara Barat has become more connected. Nusa Tenggara Barat ranked 20th in 1975, 26th in 1976-1990, 24th in 1991-2000 and 24th in 2001-2014.