Street-network Sprawl in Baja California, 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.

Baja California: 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 Baja California, Mexico on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Baja California as of 2014, the overall level of street-network sprawl is 3.87, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.41, 3.32, 4.81 and 4.78. Disconnectivity in street construction in Baja California follows a zig-zag trend. In 1976-1990, street construction was most disconnected, while construction was most connected in 1991-2000.

Quantity of street network construction: The street network in Baja California spans a total of 13365 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 3.32, 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 3.41, 3.35, 3.53 and 3.87. The SNDi of the aggregate street network in fell at first, but Baja California has worsened in disconnectivity since 1990.

The level of street-network sprawl in new development in Baja California followed a zig-zag trend with an overall increase. To get a sense of how street development has changed in Baja California, we can consider three of its most populous cities: Mexicali, Ensenada and Rosarito. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Mexicali rose steadily. The level of street-network sprawl in new development in Ensenada peaked in 1991-2000. The level of street-network sprawl in new development in Rosarito was at its lowest in 1976-1990.

How do development practices in Baja California fare in comparison to others in Mexico? Most recently in 2001-2014, street construction in Baja California was the 14th-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 Baja California has become more connected. Baja California ranked 4th in 1975, 9th in 1976-1990, 5th in 1991-2000 and 14th in 2001-2014.

As of 2014, the city with the most disconnected street network in Baja California is Las Delicias with an SNDi of 8.8, which is highly disconnected. Conversely, the most connected city is Mexicali with an SNDi of 2.04, which is relatively well-connected. See trends for these cities: Mexicali, Las Delicias

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

To date, Baja California is the 4th-most disconnected out of the 32 regions in Mexico. Its position in the ranks since 1975 has not changed. Baja California ranked 4th in 1975, 4th in 1976-1990, 5th in 1991-2000 and 4th in 2001-2014.