Street-network Sprawl in Graz, Austria

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.

Graz: city in Steiermark, Austria

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 Graz, Austria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Graz as of 2014, the overall level of street-network sprawl is 2.31, 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 2.26, nan, 7.27 and 2.38. Data was not available in 1976-1990.

Quantity of street network construction: The street network in Graz spans a total of 845 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 2.26, 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 2.26, 2.26, 2.31 and 2.31. Overall, the SNDi of the aggregate street network has risen: the street network in Graz has become more disconnected.

Graz and Steiermark do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in Steiermark rose steadily.

How do development practices in Graz fare in comparison to others in Steiermark? Most recently in 2001-2014, street construction in Graz was the 1st-most disconnected out of the 1 cities in Steiermark. Its position in the ranks since 1975 has not changed. Graz ranked 1st in 1975, 1st in 1991-2000 and 1st in 2001-2014. There was no ranking in 1976-1990 due to unavailable data.

Graz and Austria do not follow the same trend in the disconnectivity of their street network constructions. There was not enough data from the city, while the SNDi of street constructions in Austria peaked in 1991-2000.

How do development practices in Graz fare in comparison to others in Austria? Most recently in 2001-2014, street construction in Graz was the 3rd-most disconnected out of the 6 cities in Austria. Its position in the ranks since 1975 has fallen; relative to other cities in Austria, street construction in Graz has become more connected. Graz ranked 1st in 1975, 1st in 1991-2000 and 3rd in 2001-2014. There was no ranking in 1976-1990 due to unavailable data.

Graz and Steiermark do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Graz rose steadily, while the SNDi of street constructions in Steiermark rose steadily.

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

Graz and Austria do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Graz rose steadily, while the SNDi of street constructions in Austria rose steadily.

To date, Graz is the 1st-most disconnected out of the 6 cities in Austria. Its position in the ranks since 1975 has not changed. Graz ranked 1st in 1975, 1st in 1976-1990, 1st in 1991-2000 and 1st in 2001-2014.

As of 2015, Graz had a built-up area of 38.38 square kilometers, and a population of 261476 people.

These are some other cities with approximately the same population: