Street-network Sprawl in Sidi Bel Abbès, Algeria

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.

Sidi Bel Abbès: region in Algeria

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 Sidi Bel Abbès, Algeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sidi Bel Abbès as of 2014, the overall level of street-network sprawl is 1.39, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.75, 1.32, 1.83 and 1.57. Street construction in Sidi Bel Abbès 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 Sidi Bel Abbès spans a total of 4035 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 1.32, 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 0.75, 1.32, 1.4 and 1.39. The aggregate street network in Sidi Bel Abbès increased in disconnectivity initially,but the trend has turned around after 2000.

The level of street-network sprawl in new development in Sidi Bel Abbès peaked in 1991-2000. To get a sense of how street development has changed in Sidi Bel Abbès, we can consider one of its most populous cities: Sidi Bel Abbes. Disconnectivity in the most populous cities in Sidi Bel Abbès follow the same region trend.

How do development practices in Sidi Bel Abbès fare in comparison to others in Algeria? Most recently in 2001-2014, street construction in Sidi Bel Abbès was the 35th-most disconnected out of the 46 regions in Algeria. Its position in the ranks since 1975 has risen; relative to other regions in Algeria, street construction in Sidi Bel Abbès has become more disconnected. Sidi Bel Abbès ranked 42nd in 1975, 34th in 1976-1990, 29th in 1991-2000 and 35th in 2001-2014.

As of 2014, the city with the most disconnected street network in Sidi Bel Abbès is Sidi Bel Abbes with an SNDi of 1.47, which is relatively well-connected. Conversely, the most connected city is Sidi Bel Abbes with an SNDi of 1.47, which is relatively well-connected. See trends for these cities: Sidi Bel Abbes, Sidi Bel Abbes

The level of street-network sprawl in the aggregate network in Sidi Bel Abbès peaked in 1991-2000. To get a sense of how the aggregate street network has changed in Sidi Bel Abbès, we can consider one of its most populous cities: Sidi Bel Abbes. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Sidi Bel Abbes peaked in 1976-1990.

To date, Sidi Bel Abbès is the 34th-most disconnected out of the 46 regions in Algeria. Its position in the ranks since 1975 has risen; relative to other regions in Algeria, the street network in Sidi Bel Abbès has become more disconnected. Sidi Bel Abbès ranked 42nd in 1975, 36th in 1976-1990, 33rd in 1991-2000 and 34th in 2001-2014.