Street-network Sprawl in Rio Grande do Sul, Brazil

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.

Rio Grande do Sul: region in Brazil

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 Rio Grande do Sul, Brazil on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Rio Grande do Sul as of 2014, the overall level of street-network sprawl is 2.38, 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 1.22, 2.25, 3.46 and 4.61. In each period, new street development in Rio Grande do Sul steadily grows more disconnected than in the last.

Quantity of street network construction: The street network in Rio Grande do Sul spans a total of 90498 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 2.25, 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 1.22, 1.86, 2.12 and 2.38. Overall, the SNDi of the aggregate street network has risen: the street network in Rio Grande do Sul has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.64 points, but between 1991-2000 and 2001-2014, it rose by just 0.26.

The level of street-network sprawl in new development in Rio Grande do Sul rose steadily. To get a sense of how street development has changed in Rio Grande do Sul, we can consider three of its most populous cities: Porto Alegre, Novo Hamburgo and Caxias do Sul. Disconnectivity in the most populous cities in Rio Grande do Sul follow the same region trend.

How do development practices in Rio Grande do Sul fare in comparison to others in Brazil? Most recently in 2001-2014, street construction in Rio Grande do Sul was the 7th-most disconnected out of the 29 regions in Brazil. Its position in the ranks since 1975 has risen; relative to other regions in Brazil, street construction in Rio Grande do Sul has become more disconnected. Rio Grande do Sul ranked 25th in 1975, 8th in 1976-1990, 8th in 1991-2000 and 7th in 2001-2014.

As of 2014, the city with the most disconnected street network in Rio Grande do Sul is Bento Gonçalves with an SNDi of 3.65, which is highly disconnected. Conversely, the most connected city is Tramandaí with an SNDi of 0.15, which is very well-connected. See trends for these cities: Tramandaí, Bento Gonçalves

The level of street-network sprawl in the aggregate network in Rio Grande do Sul rose steadily. To get a sense of how the aggregate street network has changed in Rio Grande do Sul, we can consider three of its most populous cities: Porto Alegre, Novo Hamburgo and Caxias do Sul. Disconnectivity in the most populous cities in Rio Grande do Sul follow the same region trend.

To date, Rio Grande do Sul is the 15th-most disconnected out of the 29 regions in Brazil. Its position in the ranks since 1975 has risen; relative to other regions in Brazil, the street network in Rio Grande do Sul has become more disconnected. Rio Grande do Sul ranked 25th in 1975, 19th in 1976-1990, 16th in 1991-2000 and 15th in 2001-2014.