Street-network Sprawl in Sidi Bouzid, Tunisia

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 Bouzid: city in Sidi Bou Zid, Tunisia

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 Bouzid, Tunisia on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Sidi Bouzid as of 2014, the overall level of street-network sprawl is 0.47, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.3, 0.37, 0.65 and 0.74. The disconnectivity of new streets constructed in Sidi Bouzid fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Sidi Bouzid spans a total of 230 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 0.37, which is very 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 2.3, 0.38, 0.45 and 0.47. The SNDi of the aggregate street network in fell at first, but Sidi Bouzid has worsened in disconnectivity since 1990.

Sidi Bouzid and Sidi Bou Zid 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 Sidi Bouzid fare in comparison to others in Sidi Bou Zid? Most recently in 2001-2014, street construction in Sidi Bouzid was the 2nd-most disconnected out of the 2 cities in Sidi Bou Zid. Its position in the ranks since 1975 has fallen; relative to other cities in Sidi Bou Zid, street construction in Sidi Bouzid has become more connected. Sidi Bouzid ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 2nd in 2001-2014.

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

How do development practices in Sidi Bouzid fare in comparison to others in Tunisia? Most recently in 2001-2014, street construction in Sidi Bouzid was the 19th-most disconnected out of the 26 cities in Tunisia. Its position in the ranks since 1975 has fallen; relative to other cities in Tunisia, street construction in Sidi Bouzid has become more connected. Sidi Bouzid ranked 3rd in 1975, 24th in 1976-1990, 17th in 1991-2000 and 19th in 2001-2014.

Sidi Bouzid and Sidi Bou Zid 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, Sidi Bouzid is the 1st-most disconnected out of the 2 cities in Sidi Bou Zid. Its position in the ranks since 1975 has not changed. Sidi Bouzid ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

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

To date, Sidi Bouzid is the 23rd-most disconnected out of the 26 cities in Tunisia. Its position in the ranks since 1975 has fallen; relative to other cities in Tunisia, the street network in Sidi Bouzid has become more connected. Sidi Bouzid ranked 3rd in 1975, 24th in 1976-1990, 23rd in 1991-2000 and 23rd in 2001-2014.

As of 2015, Sidi Bouzid had a built-up area of 5.62 square kilometers, and a population of 81656 people.

These are some other cities with approximately the same population: