Street-network Sprawl in Tacna, Peru

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.

Tacna: city in Peru

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 Tacna, Peru on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Tacna as of 2014, the overall level of street-network sprawl is 0.61, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 1.04, 0.3, 0.57 and 0.08. Disconnectivity in street construction in Tacna follows a zig-zag trend. In 2001-2014, street construction was most disconnected, while construction was most connected in 1975.

Quantity of street network construction: The street network in Tacna spans a total of 827 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 1.04, 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 1.04, 1.01, 0.98 and 0.61. Overall, the SNDi of the aggregate street network has fallen: the street network in Tacna has become more connected. This decrease has quickened: between 1975 and 1976-1990, SNDi fell by 0.03 points, but between 1991-2000 and 2001-2014, it fell by just 0.37.

Tacna and Tacna do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Tacna followed a zig-zag trend with an overall decrease, while the SNDi of street constructions in Tacna peaked in 1976-1990.

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

Tacna and Peru follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these followed a zig-zag trend with an overall decrease.

How do development practices in Tacna fare in comparison to others in Peru? Most recently in 2001-2014, street construction in Tacna was the 33rd-most disconnected out of the 49 cities in Peru. Its position in the ranks since 1975 has fallen; relative to other cities in Peru, street construction in Tacna has become more connected. Tacna ranked 21st in 1975, 10th in 1976-1990, 26th in 1991-2000 and 33rd in 2001-2014.

Tacna and Tacna do not follow the same trend in the disconnectivity of their aggregate street networks. The SNDi in Tacna fell steadily, while the SNDi of street constructions in Tacna peaked in 1991-2000.

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

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

To date, Tacna is the 39th-most disconnected out of the 49 cities in Peru. Its position in the ranks since 1975 has fallen; relative to other cities in Peru, the street network in Tacna has become more connected. Tacna ranked 21st in 1975, 24th in 1976-1990, 25th in 1991-2000 and 39th in 2001-2014.

As of 2015, Tacna had a built-up area of 18.37 square kilometers, and a population of 262176 people.

These are some other cities with approximately the same population: