Street-network Sprawl in Najaf, 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.

Najaf: city in An-Najaf, 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 Najaf, Iraq on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Najaf as of 2014, the overall level of street-network sprawl is 1.37, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are -0.03, 1.08, 1.07 and 1.54. Disconnectivity in street construction in Najaf follows a zig-zag trend. In 1975, street construction was most disconnected, while construction was most connected in 2001-2014.

Quantity of street network construction: The street network in Najaf spans a total of 1526 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 1.54, 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 -0.03, 1.08, 1.08 and 1.37. Overall, the SNDi of the aggregate street network has risen: the street network in Najaf has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 1.11 points, but between 1991-2000 and 2001-2014, it rose by just 0.29.

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

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

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

How do development practices in Najaf fare in comparison to others in Iraq? Most recently in 2001-2014, street construction in Najaf was the 50th-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 Najaf has become more connected. Najaf ranked 45th in 1975, 52nd in 1976-1990, 44th in 1991-2000 and 50th in 2001-2014.

Najaf and An-Najaf do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Najaf rose steadily, while the SNDi of street constructions in An-Najaf followed a zig-zag trend with an overall increase.

To date, Najaf is the 1st-most disconnected out of the 2 cities in An-Najaf. Its position in the ranks since 1975 has risen; relative to other cities in An-Najaf, the street network in Najaf has become more disconnected. Najaf ranked 2nd in 1975, 2nd in 1976-1990, 2nd in 1991-2000 and 1st in 2001-2014.

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

To date, Najaf is the 54th-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 Najaf has become more connected. Najaf ranked 45th in 1975, 51st in 1976-1990, 55th in 1991-2000 and 54th in 2001-2014.

As of 2015, Najaf had a built-up area of 32.84 square kilometers, and a population of 1012532 people.

These are some other cities with approximately the same population: