Street-network Sprawl in Ndola, Zambia

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.

Ndola: city in Copperbelt, Zambia

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 Ndola, Zambia on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Ndola as of 2014, the overall level of street-network sprawl is 2.16, which is relatively well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.13, 2.02, 2.32 and 3.36. The disconnectivity of new streets constructed in Ndola fell, then rose. In 1976-1990, new street layouts were the most connected.

Quantity of street network construction: The street network in Ndola spans a total of 923 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 2.13, 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 2.13, 2.11, 2.12 and 2.16. The SNDi of the aggregate street network in fell at first, but Ndola has worsened in disconnectivity since 1990.

Ndola and Copperbelt do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Ndola was at its lowest in 1976-1990, while the SNDi of street constructions in Copperbelt followed a zig-zag trend with an overall increase.

How do development practices in Ndola fare in comparison to others in Copperbelt? Most recently in 2001-2014, street construction in Ndola was the 2nd-most disconnected out of the 6 cities in Copperbelt. Its position in the ranks since 1975 has not changed. Ndola ranked 2nd in 1975, 5th in 1976-1990, 3rd in 1991-2000 and 2nd in 2001-2014.

Ndola and Zambia do not follow the same trend in the disconnectivity of their street network constructions. The SNDi in Ndola was at its lowest in 1976-1990, while the SNDi of street constructions in Zambia rose steadily.

How do development practices in Ndola fare in comparison to others in Zambia? Most recently in 2001-2014, street construction in Ndola was the 11th-most disconnected out of the 38 cities in Zambia. Its position in the ranks since 1975 has risen; relative to other cities in Zambia, street construction in Ndola has become more disconnected. Ndola ranked 12th in 1975, 18th in 1976-1990, 13th in 1991-2000 and 11th in 2001-2014.

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

To date, Ndola is the 2nd-most disconnected out of the 6 cities in Copperbelt. Its position in the ranks since 1975 has not changed. Ndola ranked 2nd in 1975, 2nd in 1976-1990, 2nd in 1991-2000 and 2nd in 2001-2014.

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

To date, Ndola is the 19th-most disconnected out of the 38 cities in Zambia. Its position in the ranks since 1975 has fallen; relative to other cities in Zambia, the street network in Ndola has become more connected. Ndola ranked 12th in 1975, 12th in 1976-1990, 14th in 1991-2000 and 19th in 2001-2014.

As of 2015, Ndola had a built-up area of 39.75 square kilometers, and a population of 439792 people.

These are some other cities with approximately the same population:

For some related information about population, urban extent and density, and roads, visit the Atlas of Urban Expansion.