Street-network Sprawl in Al Qa`idah, Yemen

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.

Al Qa`idah: city in Ibb, Yemen

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 Al Qa`idah, Yemen on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Al Qa`idah as of 2014, the overall level of street-network sprawl is 1.23, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 4.01, 1.77, nan and 0.95. Data was not available in 1991-2000.

Quantity of street network construction: The street network in Al Qa`idah spans a total of 67 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 0.95, 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 4.01, 2.48, 2.87 and 1.23. Disconnectivity in Al Qa`idah's street network follows a zig-zag trend. In 2001-2014, the city was most disconnected; while it was most connected in 1975.

Al Qa`idah and Ibb do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in Ibb followed a zig-zag trend with an overall decrease.

How do development practices in Al Qa`idah fare in comparison to others in Ibb? Most recently in 2001-2014, street construction in Al Qa`idah was the 3rd-most disconnected out of the 3 cities in Ibb. Its position in the ranks since 1975 has not changed. Al Qa`idah ranked 2nd in 1975, 2nd in 1976-1990 and 3rd in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

Al Qa`idah and Yemen do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in Yemen followed a zig-zag trend with an overall decrease.

How do development practices in Al Qa`idah fare in comparison to others in Yemen? Most recently in 2001-2014, street construction in Al Qa`idah was the 28th-most disconnected out of the 36 cities in Yemen. Its position in the ranks since 1975 has fallen; relative to other cities in Yemen, street construction in Al Qa`idah has become more connected. Al Qa`idah ranked 5th in 1975, 13th in 1976-1990 and 28th in 2001-2014. There was no ranking in 1991-2000 due to unavailable data.

Al Qa`idah and Ibb do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Al Qa`idah followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Ibb fell steadily.

To date, Al Qa`idah is the 2nd-most disconnected out of the 3 cities in Ibb. Its position in the ranks since 1975 has not changed. Al Qa`idah ranked 2nd in 1975, 2nd in 1976-1990, 2nd in 1991-2000 and 2nd in 2001-2014.

Al Qa`idah and Yemen do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Al Qa`idah followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Yemen was at its lowest in 1976-1990.

To date, Al Qa`idah is the 30th-most disconnected out of the 36 cities in Yemen. Its position in the ranks since 1975 has fallen; relative to other cities in Yemen, the street network in Al Qa`idah has become more connected. Al Qa`idah ranked 5th in 1975, 11th in 1976-1990, 9th in 1991-2000 and 30th in 2001-2014.

As of 2015, Al Qa`idah had a built-up area of 0.22 square kilometers, and a population of 167164 people.

These are some other cities with approximately the same population: