Street-network Sprawl in Ohio, United States

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.

Ohio: region in United States

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 Ohio, United States on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Ohio as of 2014, the overall level of street-network sprawl is 3.62, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 2.77, 4.29, 5.68 and 5.51. Street construction in Ohio 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 Ohio spans a total of 188466 kilometers. The period with the greatest volume of street construction was 1975. These roads have an SNDi of 2.77, which is in the 40th to 60th percentile of disconnectedness.

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 2.77, 3.16, 3.47 and 3.62. Overall, the SNDi of the aggregate street network has risen: the street network in Ohio has become more disconnected. This increase has slowed: between 1975 and 1976-1990, SNDi rose by 0.39 points, but between 1991-2000 and 2001-2014, it rose by just 0.14.

The level of street-network sprawl in new development in Ohio peaked in 1991-2000. To get a sense of how street development has changed in Ohio, we can consider three of its most populous cities: Cleveland, Columbus and Cincinnati. Out of the three cities, Columbus does not follow the same trend as the region. The level of street-network sprawl in new development in Columbus peaked in 1976-1990.

How do development practices in Ohio fare in comparison to others in United States? Most recently in 2001-2014, street construction in Ohio was the 25th-most disconnected out of the 46 regions in United States. Its position in the ranks since 1975 has risen; relative to other regions in United States, street construction in Ohio has become more disconnected. Ohio ranked 27th in 1975, 25th in 1976-1990, 25th in 1991-2000 and 25th in 2001-2014.

As of 2014, the city with the most disconnected street network in Ohio is North College Hill with an SNDi of 5.89, which is highly disconnected. Conversely, the most connected city is Toledo with an SNDi of 1.69, which is relatively well-connected. See trends for these cities: Toledo, North College Hill

The level of street-network sprawl in the aggregate network in Ohio rose steadily. To get a sense of how the aggregate street network has changed in Ohio, we can consider three of its most populous cities: Cleveland, Columbus and Cincinnati. Disconnectivity in the most populous cities in Ohio follow the same region trend.

To date, Ohio is the 27th-most disconnected out of the 46 regions in United States. Its position in the ranks since 1975 has not changed. Ohio ranked 27th in 1975, 28th in 1976-1990, 26th in 1991-2000 and 27th in 2001-2014.