Street-network Sprawl in Ikorodu, Nigeria

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.

Ikorodu: city in Lagos, Nigeria

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 Ikorodu, Nigeria on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Ikorodu as of 2014, the overall level of street-network sprawl is 4.35, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.4, 3.47, 4.9 and 4.44. Street construction in Ikorodu 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 Ikorodu spans a total of 2675 kilometers. The period with the greatest volume of street construction was 1991-2000. These roads have an SNDi of 4.9, which is highly disconnected.

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 3.4, 3.44, 4.29 and 4.35. Overall, the SNDi of the aggregate street network has risen: the street network in Ikorodu has become more disconnected.

Ikorodu and Lagos follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these peaked in 1991-2000.

How do development practices in Ikorodu fare in comparison to others in Lagos? Most recently in 2001-2014, street construction in Ikorodu was the 5th-most disconnected out of the 5 cities in Lagos. Its position in the ranks since 1975 has fallen; relative to other cities in Lagos, street construction in Ikorodu has become more connected. Ikorodu ranked 2nd in 1975, 4th in 1976-1990, 5th in 1991-2000 and 5th in 2001-2014.

Ikorodu and Nigeria follow the same trend in the disconnectivity of their street network constructions. The SNDi for both of these peaked in 1991-2000.

How do development practices in Ikorodu fare in comparison to others in Nigeria? Most recently in 2001-2014, street construction in Ikorodu was the 102nd-most disconnected out of the 411 cities in Nigeria. Its position in the ranks since 1975 has fallen; relative to other cities in Nigeria, street construction in Ikorodu has become more connected. Ikorodu ranked 32nd in 1975, 77th in 1976-1990, 55th in 1991-2000 and 102nd in 2001-2014.

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

To date, Ikorodu is the 4th-most disconnected out of the 5 cities in Lagos. Its position in the ranks since 1975 has fallen; relative to other cities in Lagos, the street network in Ikorodu has become more connected. Ikorodu ranked 2nd in 1975, 4th in 1976-1990, 4th in 1991-2000 and 4th in 2001-2014.

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

To date, Ikorodu is the 46th-most disconnected out of the 411 cities in Nigeria. Its position in the ranks since 1975 has fallen; relative to other cities in Nigeria, the street network in Ikorodu has become more connected. Ikorodu ranked 32nd in 1975, 51st in 1976-1990, 33rd in 1991-2000 and 46th in 2001-2014.

As of 2015, Ikorodu had a built-up area of 132.4 square kilometers, and a population of 790812 people.

These are some other cities with approximately the same population: