Street-network Sprawl in Tours, France

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.

Tours: city in Centre-Val de Loire, France

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 Tours, France on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Tours as of 2014, the overall level of street-network sprawl is 1.92, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.64, 2.83, 1.49 and 2.27. Disconnectivity in street construction in Tours follows a zig-zag trend. In 1991-2000, street construction was most disconnected, while construction was most connected in 1976-1990.

Quantity of street network construction: The street network in Tours spans a total of 1068 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 1.64, 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 1.64, 1.93, 1.92 and 1.92. Disconnectivity in Tours's street network follows a zig-zag trend. In 1975, the city was most disconnected; while it was most connected in 1976-1990.

Tours and Centre-Val de Loire do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Tours followed a zig-zag trend with an overall increase, while the SNDi of street constructions in Centre-Val de Loire rose steadily.

How do development practices in Tours fare in comparison to others in Centre-Val de Loire? Most recently in 2001-2014, street construction in Tours was the 3rd-most disconnected out of the 3 cities in Centre-Val de Loire. Its position in the ranks since 1975 has not changed. Tours ranked 3rd in 1975, 2nd in 1976-1990, 3rd in 1991-2000 and 3rd in 2001-2014.

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

How do development practices in Tours fare in comparison to others in France? Most recently in 2001-2014, street construction in Tours was the 67th-most disconnected out of the 76 cities in France. Its position in the ranks since 1975 has fallen; relative to other cities in France, street construction in Tours has become more connected. Tours ranked 52nd in 1975, 53rd in 1976-1990, 64th in 1991-2000 and 67th in 2001-2014.

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

To date, Tours is the 3rd-most disconnected out of the 3 cities in Centre-Val de Loire. Its position in the ranks since 1975 has not changed. Tours ranked 3rd in 1975, 3rd in 1976-1990, 3rd in 1991-2000 and 3rd in 2001-2014.

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

To date, Tours is the 54th-most disconnected out of the 76 cities in France. Its position in the ranks since 1975 has fallen; relative to other cities in France, the street network in Tours has become more connected. Tours ranked 52nd in 1975, 51st in 1976-1990, 53rd in 1991-2000 and 54th in 2001-2014.

As of 2015, Tours had a built-up area of 50.09 square kilometers, and a population of 211590 people.

These are some other cities with approximately the same population: