Street-network Sprawl in Sabha, Libya

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.

Sabha: city in Libya

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 Sabha, Libya on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sabha as of 2014, the overall level of street-network sprawl is 1.02, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.05, 0.65, 2.03 and 3.5. The disconnectivity of new streets constructed in Sabha fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Sabha spans a total of 314 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 0.65, 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 2.05, 0.71, 0.86 and 1.02. The SNDi of the aggregate street network in fell at first, but Sabha has worsened in disconnectivity since 1990.

Sabha and Sabha follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these was at its lowest in 1976-1990.

How do development practices in Sabha fare in comparison to others in Sabha? Most recently in 2001-2014, street construction in Sabha was the 1st-most disconnected out of the 1 cities in Sabha. Its position in the ranks since 1975 has not changed. Sabha ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

Sabha and Libya do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Sabha was at its lowest in 1976-1990, while the SNDi of street constructions in Libya rose steadily.

How do development practices in Sabha fare in comparison to others in Libya? Most recently in 2001-2014, street construction in Sabha was the 8th-most disconnected out of the 15 cities in Libya. Its position in the ranks since 1975 has fallen; relative to other cities in Libya, street construction in Sabha has become more connected. Sabha ranked 5th in 1975, 13th in 1976-1990, 10th in 1991-2000 and 8th in 2001-2014.

Sabha and Sabha follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these was at its lowest in 1976-1990.

To date, Sabha is the 1st-most disconnected out of the 1 cities in Sabha. Its position in the ranks since 1975 has not changed. Sabha ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

Sabha and Libya do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Sabha was at its lowest in 1976-1990, while the SNDi of street constructions in Libya rose steadily.

To date, Sabha is the 13th-most disconnected out of the 15 cities in Libya. Its position in the ranks since 1975 has fallen; relative to other cities in Libya, the street network in Sabha has become more connected. Sabha ranked 5th in 1975, 14th in 1976-1990, 14th in 1991-2000 and 13th in 2001-2014.

As of 2015, Sabha had a built-up area of 11.74 square kilometers, and a population of 113114 people.

These are some other cities with approximately the same population: