Street-network Sprawl in Amran, Yemen

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.

Amran: city in Yemen

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 Amran, Yemen on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Amran as of 2014, the overall level of street-network sprawl is 2.63, which is in the 40th to 60th percentile of disconnectedness.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.18, 2.96, 0.9 and 2.58. The disconnectivity of new streets constructed in Amran fell, then rose. In 1991-2000, new street layouts were the most connected.

Quantity of street network construction: The street network in Amran spans a total of 138 kilometers. It is dominated by roads constructed in 2001-2014. These roads have an SNDi of 2.58, which is in the 40th to 60th percentile of disconnectedness.

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 3.18, 2.99, 2.78 and 2.63. Overall, the SNDi of the aggregate street network has fallen: the street network in Amran has become more connected.

Amran and Amran follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these was at its lowest in 1991-2000.

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

Amran and Yemen do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Amran was at its lowest in 1991-2000, while the SNDi of street constructions in Yemen followed a zig-zag trend with an overall decrease.

How do development practices in Amran fare in comparison to others in Yemen? Most recently in 2001-2014, street construction in Amran was the 14th-most disconnected out of the 36 cities in Yemen. Its position in the ranks since 1975 has fallen; relative to other cities in Yemen, street construction in Amran has become more connected. Amran ranked 7th in 1975, 7th in 1976-1990, 17th in 1991-2000 and 14th in 2001-2014.

Amran and Amran do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Amran fell steadily, while the SNDi of street constructions in Amran was at its lowest in 1991-2000.

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

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

To date, Amran is the 17th-most disconnected out of the 36 cities in Yemen. Its position in the ranks since 1975 has fallen; relative to other cities in Yemen, the street network in Amran has become more connected. Amran ranked 7th in 1975, 7th in 1976-1990, 11th in 1991-2000 and 17th in 2001-2014.

As of 2015, Amran had a built-up area of 0.51 square kilometers, and a population of 156875 people.

These are some other cities with approximately the same population: