Street-network Sprawl in Basra, Iraq

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.

Basra: city in Al-Basrah, Iraq

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 Basra, Iraq on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Basra as of 2014, the overall level of street-network sprawl is 1.88, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.08, 1.68, 2.21 and 2.32. The disconnectivity of new streets constructed in Basra fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Basra spans a total of 1863 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 1.68, 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 2.08, 1.83, 1.84 and 1.88. The SNDi of the aggregate street network in fell at first, but Basra has worsened in disconnectivity since 1990.

Basra and Al-Basrah do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Basra was at its lowest in 1976-1990, while the SNDi of street constructions in Al-Basrah followed a zig-zag trend with an overall increase.

How do development practices in Basra fare in comparison to others in Al-Basrah? Most recently in 2001-2014, street construction in Basra was the 2nd-most disconnected out of the 6 cities in Al-Basrah. Its position in the ranks since 1975 has risen; relative to other cities in Al-Basrah, street construction in Basra has become more disconnected. Basra ranked 4th in 1975, 4th in 1976-1990, 1st in 1991-2000 and 2nd in 2001-2014.

Basra and Iraq 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 Basra fare in comparison to others in Iraq? Most recently in 2001-2014, street construction in Basra was the 28th-most disconnected out of the 75 cities in Iraq. Its position in the ranks since 1975 has fallen; relative to other cities in Iraq, street construction in Basra has become more connected. Basra ranked 20th in 1975, 25th in 1976-1990, 17th in 1991-2000 and 28th in 2001-2014.

Basra and Al-Basrah 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, Basra is the 4th-most disconnected out of the 6 cities in Al-Basrah. Its position in the ranks since 1975 has not changed. Basra ranked 4th in 1975, 4th in 1976-1990, 4th in 1991-2000 and 4th in 2001-2014.

Basra and Iraq 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, Basra is the 26th-most disconnected out of the 75 cities in Iraq. Its position in the ranks since 1975 has fallen; relative to other cities in Iraq, the street network in Basra has become more connected. Basra ranked 20th in 1975, 21st in 1976-1990, 21st in 1991-2000 and 26th in 2001-2014.

As of 2015, Basra had a built-up area of 23.46 square kilometers, and a population of 1484284 people.

These are some other cities with approximately the same population: