Street-network Sprawl in Miyakonojo, Japan

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.

Miyakonojo: city in Miyazaki, Japan

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 Miyakonojo, Japan on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Miyakonojo as of 2014, the overall level of street-network sprawl is 0.1, which is very well-connected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 0.09, 0.22, 0.79 and 0.34. Street construction in Miyakonojo 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 Miyakonojo spans a total of 586 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 0.09, which is very 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 0.09, 0.09, 0.1 and 0.1. The aggregate street network in Miyakonojo increased in disconnectivity initially,but the trend has turned around after 2000.

Miyakonojo and Miyazaki 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 Miyakonojo fare in comparison to others in Miyazaki? Most recently in 2001-2014, street construction in Miyakonojo was the 3rd-most disconnected out of the 3 cities in Miyazaki. Its position in the ranks since 1975 has not changed. Miyakonojo ranked 3rd in 1975, 2nd in 1976-1990, 2nd in 1991-2000 and 3rd in 2001-2014.

Miyakonojo and Japan 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 Miyakonojo fare in comparison to others in Japan? Most recently in 2001-2014, street construction in Miyakonojo was the 89th-most disconnected out of the 109 cities in Japan. Its position in the ranks since 1975 has risen; relative to other cities in Japan, street construction in Miyakonojo has become more disconnected. Miyakonojo ranked 109th in 1975, 95th in 1976-1990, 89th in 1991-2000 and 89th in 2001-2014.

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

To date, Miyakonojo is the 3rd-most disconnected out of the 3 cities in Miyazaki. Its position in the ranks since 1975 has not changed. Miyakonojo ranked 3rd in 1975, 3rd in 1976-1990, 3rd in 1991-2000 and 3rd in 2001-2014.

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

To date, Miyakonojo is the 109th-most disconnected out of the 109 cities in Japan. Its position in the ranks since 1975 has not changed. Miyakonojo ranked 109th in 1975, 109th in 1976-1990, 109th in 1991-2000 and 109th in 2001-2014.

As of 2015, Miyakonojo had a built-up area of 24.46 square kilometers, and a population of 77226 people.

These are some other cities with approximately the same population: