Street-network Sprawl in Libertador General Bernardo O'Higgins, Chile

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.

Libertador General Bernardo O'Higgins: region in Chile

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 Libertador General Bernardo O'Higgins, Chile on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Libertador General Bernardo O'Higgins as of 2014, the overall level of street-network sprawl is 3.97, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.62, 3.24, 4.27 and 5.24. The disconnectivity of new streets constructed in Libertador General Bernardo O'Higgins fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Libertador General Bernardo O'Higgins spans a total of 7192 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 3.24, 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 3.62, 3.33, 3.55 and 3.97. The SNDi of the aggregate street network in fell at first, but Libertador General Bernardo O'Higgins has worsened in disconnectivity since 1990.

The level of street-network sprawl in new development in Libertador General Bernardo O'Higgins was at its lowest in 1976-1990. To get a sense of how street development has changed in Libertador General Bernardo O'Higgins, we can consider two of its most populous cities: Rancagua and San Fernando. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Rancagua followed a zig-zag trend. The level of street-network sprawl in new development in San Fernando peaked in 1991-2000.

How do development practices in Libertador General Bernardo O'Higgins fare in comparison to others in Chile? Most recently in 2001-2014, street construction in Libertador General Bernardo O'Higgins was the 2nd-most disconnected out of the 16 regions in Chile. Its position in the ranks since 1975 has risen; relative to other regions in Chile, street construction in Libertador General Bernardo O'Higgins has become more disconnected. Libertador General Bernardo O'Higgins ranked 3rd in 1975, 5th in 1976-1990, 3rd in 1991-2000 and 2nd in 2001-2014.

As of 2014, the city with the most disconnected street network in Libertador General Bernardo O'Higgins is Rancagua with an SNDi of 2.79, which is in the 40th to 60th percentile of disconnectedness. Conversely, the most connected city is San Fernando with an SNDi of 2.5, which is in the 40th to 60th percentile of disconnectedness. See trends for these cities: San Fernando, Rancagua

The level of street-network sprawl in the aggregate network in Libertador General Bernardo O'Higgins was at its lowest in 1976-1990. To get a sense of how the aggregate street network has changed in Libertador General Bernardo O'Higgins, we can consider two of its most populous cities: Rancagua and San Fernando. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Rancagua followed a zig-zag trend. The level of street-network sprawl in the aggregate network in San Fernando peaked in 1991-2000.

To date, Libertador General Bernardo O'Higgins is the 1st-most disconnected out of the 16 regions in Chile. Its position in the ranks since 1975 has risen; relative to other regions in Chile, the street network in Libertador General Bernardo O'Higgins has become more disconnected. Libertador General Bernardo O'Higgins ranked 3rd in 1975, 2nd in 1976-1990, 3rd in 1991-2000 and 1st in 2001-2014.