Street-network Sprawl in Somalia

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.

Somalia

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 Somalia on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Somalia as of 2014, the overall level of street-network sprawl is 2.24, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.48, 2.44, 3.32 and 2.02. Street construction in Somalia 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 Somalia spans a total of 37250 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 2.02, 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 1.48, 2.1, 2.41 and 2.24. The aggregate street network in Somalia increased in disconnectivity initially,but the trend has turned around after 2000.

The level of street-network sprawl in new development in Somalia peaked in 1991-2000. To get a sense of how street development has changed in Somalia, we can consider three of its most populous regions: Banaadir, Woqooyi Galbeed and Bay. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in new development in Banaadir rose steadily. The level of street-network sprawl in new development in Woqooyi Galbeed peaked in 1976-1990. The level of street-network sprawl in new development in Bay followed a zig-zag trend with an overall decrease.

How do development practices in Somalia fare in comparison to others in the world? Most recently in 2001-2014, street construction in Somalia was the 152nd-most disconnected out of the 155 countries in the world. Its position in the ranks since 1975 has fallen; relative to other countries in the world, street construction in Somalia has become more connected. Somalia ranked 134th in 1975, 113th in 1976-1990, 113th in 1991-2000 and 152nd in 2001-2014.

The largest city in Somalia is Mogadishu, with a population of 1503000 people. Taking into account the entire (i.e. aggregate) street network in Mogadishu as of 2014, the overall level of street-network sprawl is 0.23, which is very well-connected. The level of street-network sprawl in new development in Mogadishu followed a zig-zag trend with an overall increase.

As of 2014, the city with the most disconnected street network in Somalia is Dhuusamareeb دوسمريب with an SNDi of 3.93, which is highly disconnected. Conversely, the most connected city is Berbera with an SNDi of -0.75, which is very well-connected. See trends for these cities: Berbera, Dhuusamareeb دوسمريب

The level of street-network sprawl in the aggregate network in Somalia peaked in 1991-2000. To get a sense of how the aggregate street network has changed in Somalia, we can consider three of its most populous regions: Banaadir, Woqooyi Galbeed and Bay. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Banaadir rose steadily. The level of street-network sprawl in the aggregate network in Woqooyi Galbeed peaked in 1976-1990. The level of street-network sprawl in the aggregate network in Bay followed a zig-zag trend with an overall decrease.

To date, Somalia is the 128th-most disconnected out of the 155 countries in the world. Its position in the ranks since 1975 has risen; relative to other countries in the world, the street network in Somalia has become more disconnected. Somalia ranked 134th in 1975, 122nd in 1976-1990, 115th in 1991-2000 and 128th in 2001-2014.

The largest city in Somalia is Mogadishu, with a population of 1503000 people. Taking into account the entire (i.e. aggregate) street network in Mogadishu as of 2014, the overall level of street-network sprawl is 0.23, which is very well-connected. The level of street-network sprawl in the aggregate network in Mogadishu followed a zig-zag trend with an overall increase.