Street-network Sprawl in Arras, 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.

Arras: city in Hauts-de-France, 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 Arras, France on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Arras as of 2014, the overall level of street-network sprawl is 1.54, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.46, 2.31, 5.81 and 3.8. Street construction in Arras increased in disconnectivity initially but has since improved. The streets constructed in 1991-2000 were the most disconnected.

Quantity of street network construction: The street network in Arras spans a total of 263 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 1.46, 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 1.46, 1.5, 1.53 and 1.54. Overall, the SNDi of the aggregate street network has risen: the street network in Arras has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.04 points, but between 1991-2000 and 2001-2014, it rose by just 0.01.

Arras and Hauts-de-France do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Arras peaked in 1991-2000, while the SNDi of street constructions in Hauts-de-France rose steadily.

How do development practices in Arras fare in comparison to others in Hauts-de-France? Most recently in 2001-2014, street construction in Arras was the 6th-most disconnected out of the 10 cities in Hauts-de-France. Its position in the ranks since 1975 has risen; relative to other cities in Hauts-de-France, street construction in Arras has become more disconnected. Arras ranked 9th in 1975, 10th in 1976-1990, 1st in 1991-2000 and 6th in 2001-2014.

Arras and France do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Arras peaked in 1991-2000, while the SNDi of street constructions in France rose steadily.

How do development practices in Arras fare in comparison to others in France? Most recently in 2001-2014, street construction in Arras was the 35th-most disconnected out of the 76 cities in France. Its position in the ranks since 1975 has risen; relative to other cities in France, street construction in Arras has become more disconnected. Arras ranked 61st in 1975, 63rd in 1976-1990, 9th in 1991-2000 and 35th in 2001-2014.

Arras and Hauts-de-France follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Arras is the 9th-most disconnected out of the 10 cities in Hauts-de-France. Its position in the ranks since 1975 has not changed. Arras ranked 9th in 1975, 10th in 1976-1990, 9th in 1991-2000 and 9th in 2001-2014.

Arras and France follow the same trend in the disconnectivity of their aggregate street networks. The SNDi for both of these rose steadily.

To date, Arras is the 68th-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 Arras has become more connected. Arras ranked 61st in 1975, 70th in 1976-1990, 69th in 1991-2000 and 68th in 2001-2014.

As of 2015, Arras had a built-up area of 13.08 square kilometers, and a population of 62771 people.

These are some other cities with approximately the same population: