Street-network Sprawl in Manisa, Turkey

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.

Manisa: region in Turkey

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 Manisa, Turkey on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Manisa as of 2014, the overall level of street-network sprawl is 2.07, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.07, 1.62, 3.12 and 3.35. The disconnectivity of new streets constructed in Manisa fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Manisa spans a total of 8537 kilometers. It is dominated by roads constructed in 1976-1990. These roads have an SNDi of 1.62, 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 2.07, 1.65, 1.88 and 2.07. The SNDi of the aggregate street network in fell at first, but Manisa has worsened in disconnectivity since 1990.

The level of street-network sprawl in new development in Manisa was at its lowest in 1976-1990. To get a sense of how street development has changed in Manisa, we can consider three of its most populous cities: Manisa, Turgutlu and Salihli. Out of the three cities, Manisa and Salihli do not follow the same trend as the region. The level of street-network sprawl in new development in Manisa followed a zig-zag trend with an overall increase. The level of street-network sprawl in new development in Salihli followed a zig-zag trend with an overall increase.

How do development practices in Manisa fare in comparison to others in Turkey? Most recently in 2001-2014, street construction in Manisa was the 35th-most disconnected out of the 71 regions in Turkey. Its position in the ranks since 1975 has risen; relative to other regions in Turkey, street construction in Manisa has become more disconnected. Manisa ranked 41st in 1975, 55th in 1976-1990, 26th in 1991-2000 and 35th in 2001-2014.

As of 2014, the city with the most disconnected street network in Manisa is Manisa with an SNDi of 1.42, which is relatively well-connected. Conversely, the most connected city is Turgutlu with an SNDi of 0.17, which is very well-connected. See trends for these cities: Turgutlu, Manisa

The level of street-network sprawl in the aggregate network in Manisa was at its lowest in 1976-1990. To get a sense of how the aggregate street network has changed in Manisa, we can consider three of its most populous cities: Manisa, Turgutlu and Salihli. Disconnectivity in the most populous cities in Manisa follow the same region trend.

To date, Manisa is the 39th-most disconnected out of the 71 regions in Turkey. Its position in the ranks since 1975 has risen; relative to other regions in Turkey, the street network in Manisa has become more disconnected. Manisa ranked 41st in 1975, 45th in 1976-1990, 42nd in 1991-2000 and 39th in 2001-2014.