Street-network Sprawl in Grand Casablanca, Morocco

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.

Grand Casablanca: region in Morocco

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 Grand Casablanca, Morocco on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Grand Casablanca as of 2014, the overall level of street-network sprawl is 1.26, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.07, 1.28, 1.37 and 2.16. In each period, new street development in Grand Casablanca steadily grows more disconnected than in the last.

Quantity of street network construction: The street network in Grand Casablanca spans a total of 6425 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 1.07, 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 1.07, 1.12, 1.13 and 1.26. Overall, the SNDi of the aggregate street network has risen: the street network in Grand Casablanca has become more disconnected.

The level of street-network sprawl in new development in Grand Casablanca rose steadily. To get a sense of how street development has changed in Grand Casablanca, we can consider two of its most populous cities: Casablanca and Dar Bouazza. Out of the two cities, Dar Bouazza does not follow the same trend as the region. The level of street-network sprawl in new development in Dar Bouazza was at its lowest in 1991-2000.

How do development practices in Grand Casablanca fare in comparison to others in Morocco? Most recently in 2001-2014, street construction in Grand Casablanca was the 7th-most disconnected out of the 14 regions in Morocco. Its position in the ranks since 1975 has risen; relative to other regions in Morocco, street construction in Grand Casablanca has become more disconnected. Grand Casablanca ranked 13th in 1975, 12th in 1976-1990, 12th in 1991-2000 and 7th in 2001-2014.

As of 2014, the city with the most disconnected street network in Grand Casablanca is Dar Bouazza with an SNDi of 2.27, which is in the 40th to 60th percentile of disconnectedness. Conversely, the most connected city is Casablanca with an SNDi of 1.23, which is relatively well-connected. See trends for these cities: Casablanca, Dar Bouazza

The level of street-network sprawl in the aggregate network in Grand Casablanca rose steadily. To get a sense of how the aggregate street network has changed in Grand Casablanca, we can consider two of its most populous cities: Casablanca and Dar Bouazza. Out of the two cities, Dar Bouazza does not follow the same trend as the region. The level of street-network sprawl in the aggregate network in Dar Bouazza was at its lowest in 1991-2000.

To date, Grand Casablanca is the 13th-most disconnected out of the 14 regions in Morocco. Its position in the ranks since 1975 has not changed. Grand Casablanca ranked 13th in 1975, 13th in 1976-1990, 13th in 1991-2000 and 13th in 2001-2014.