Street-network Sprawl in San Luis Potosí, Mexico

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.

San Luis Potosí: region in Mexico

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 San Luis Potosí, Mexico on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in San Luis Potosí as of 2014, the overall level of street-network sprawl is 3.04, 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 2.66, 2.74, 3.11 and 4.49. In each period, new street development in San Luis Potosí steadily grows more disconnected than in the last.

Quantity of street network construction: The street network in San Luis Potosí spans a total of 17589 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 2.74, 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 2.66, 2.65, 2.71 and 3.04. The SNDi of the aggregate street network in fell at first, but San Luis Potosí has worsened in disconnectivity since 1990.

The level of street-network sprawl in new development in San Luis Potosí rose steadily. To get a sense of how street development has changed in San Luis Potosí, we can consider three of its most populous cities: San Luis Potosí, Ciudad Valles and Matehuala. Out of the three cities, Matehuala does not follow the same trend as the region. The level of street-network sprawl in new development in Matehuala was at its lowest in 1976-1990.

How do development practices in San Luis Potosí fare in comparison to others in Mexico? Most recently in 2001-2014, street construction in San Luis Potosí was the 18th-most disconnected out of the 32 regions in Mexico. Its position in the ranks since 1975 has fallen; relative to other regions in Mexico, street construction in San Luis Potosí has become more connected. San Luis Potosí ranked 10th in 1975, 18th in 1976-1990, 22nd in 1991-2000 and 18th in 2001-2014.

As of 2014, the city with the most disconnected street network in San Luis Potosí is San Luis Potosí with an SNDi of 2.43, which is in the 40th to 60th percentile of disconnectedness. Conversely, the most connected city is Matehuala with an SNDi of 0.47, which is relatively well-connected. See trends for these cities: Matehuala, San Luis Potosí

The level of street-network sprawl in the aggregate network in San Luis Potosí was at its lowest in 1976-1990. To get a sense of how the aggregate street network has changed in San Luis Potosí, we can consider three of its most populous cities: San Luis Potosí, Ciudad Valles and Matehuala. Out of the three cities, San Luis Potosí and Ciudad Valles do not follow the same trend as the region. The level of street-network sprawl in the aggregate network in San Luis Potosí rose steadily. The level of street-network sprawl in the aggregate network in Ciudad Valles rose steadily.

To date, San Luis Potosí is the 17th-most disconnected out of the 32 regions in Mexico. Its position in the ranks since 1975 has fallen; relative to other regions in Mexico, the street network in San Luis Potosí has become more connected. San Luis Potosí ranked 10th in 1975, 16th in 1976-1990, 17th in 1991-2000 and 17th in 2001-2014.