Street-network Sprawl in Comunidad de Madrid, Spain

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.

Comunidad de Madrid: region in Spain

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 Comunidad de Madrid, Spain on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Comunidad de Madrid as of 2014, the overall level of street-network sprawl is 1.54, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.56, 2.28, 2.31 and 1.62. Street construction in Comunidad de Madrid increased in disconnectivity initially but has since improved. The streets constructed in 1991-2000 were the most disconnected.

Quantity of street network construction: The street network in Comunidad de Madrid spans a total of 22603 kilometers. The period with the greatest volume of street construction was 1976-1990. These roads have an SNDi of 2.28, 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 0.56, 1.43, 1.55 and 1.54. The aggregate street network in Comunidad de Madrid increased in disconnectivity initially,but the trend has turned around after 2000.

The level of street-network sprawl in new development in Comunidad de Madrid peaked in 1991-2000. To get a sense of how street development has changed in Comunidad de Madrid, we can consider three of its most populous cities: Madrid, Alcalá de Henares and Collado Villalba. Out of the three cities, Madrid and Alcalá de Henares do not follow the same trend as the region. The level of street-network sprawl in new development in Madrid peaked in 1976-1990. The level of street-network sprawl in new development in Alcalá de Henares rose steadily.

How do development practices in Comunidad de Madrid fare in comparison to others in Spain? Most recently in 2001-2014, street construction in Comunidad de Madrid was the 18th-most disconnected out of the 18 regions in Spain. Its position in the ranks since 1975 has fallen; relative to other regions in Spain, street construction in Comunidad de Madrid has become more connected. Comunidad de Madrid ranked 17th in 1975, 11th in 1976-1990, 15th in 1991-2000 and 18th in 2001-2014.

As of 2014, the city with the most disconnected street network in Comunidad de Madrid is Collado Villalba with an SNDi of 1.86, which is relatively well-connected. Conversely, the most connected city is Madrid with an SNDi of 0.89, which is relatively well-connected. See trends for these cities: Madrid, Collado Villalba

The level of street-network sprawl in the aggregate network in Comunidad de Madrid peaked in 1991-2000. To get a sense of how the aggregate street network has changed in Comunidad de Madrid, we can consider three of its most populous cities: Madrid, Alcalá de Henares and Collado Villalba. Out of the three cities, Alcalá de Henares does not follow the same trend as the region. The level of street-network sprawl in the aggregate network in Alcalá de Henares rose steadily.

To date, Comunidad de Madrid is the 15th-most disconnected out of the 18 regions in Spain. Its position in the ranks since 1975 has risen; relative to other regions in Spain, the street network in Comunidad de Madrid has become more disconnected. Comunidad de Madrid ranked 17th in 1975, 13th in 1976-1990, 14th in 1991-2000 and 15th in 2001-2014.