Street-network Sprawl in Metropolitan Manila, Philippines

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.

Metropolitan Manila: region in Philippines

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 Metropolitan Manila, Philippines on the sprawlmap

Most recent snapshot: Taking into account the entire (i.e. aggregate) street network in Metropolitan Manila as of 2014, the overall level of street-network sprawl is 3.64, which is highly disconnected.

Trends in street network construction: The SNDis of street construction for the respective time periods are 3.25, 4.51, 2.36 and 3.11. Disconnectivity in street construction in Metropolitan Manila follows a zig-zag trend. In 1991-2000, street construction was most disconnected, while construction was most connected in 1976-1990.

Quantity of street network construction: The street network in Metropolitan Manila spans a total of 11021 kilometers. It is dominated by roads constructed prior to 1975. These roads have an SNDi of 3.25, 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 3.25, 3.65, 3.65 and 3.64. The aggregate street network in Metropolitan Manila increased in disconnectivity initially,but the trend has turned around after 1990.

The level of street-network sprawl in new development in Metropolitan Manila followed a zig-zag trend with an overall decrease. To get a sense of how street development has changed in Metropolitan Manila, we can consider one of its most populous cities: Quezon City [Manila]. Disconnectivity in the most populous cities in Metropolitan Manila follow the same region trend.

How do development practices in Metropolitan Manila fare in comparison to others in Philippines? Most recently in 2001-2014, street construction in Metropolitan Manila was the 51st-most disconnected out of the 51 regions in Philippines. Its position in the ranks since 1975 has fallen; relative to other regions in Philippines, street construction in Metropolitan Manila has become more connected. Metropolitan Manila ranked 32nd in 1975, 30th in 1976-1990, 50th in 1991-2000 and 51st in 2001-2014.

As of 2014, the city with the most disconnected street network in Metropolitan Manila is Quezon City [Manila] with an SNDi of 4.54, which is highly disconnected. Conversely, the most connected city is Quezon City [Manila] with an SNDi of 4.54, which is highly disconnected. See trends for these cities: Quezon City [Manila], Quezon City [Manila]

The level of street-network sprawl in the aggregate network in Metropolitan Manila peaked in 1976-1990. To get a sense of how the aggregate street network has changed in Metropolitan Manila, we can consider one of its most populous cities: Quezon City [Manila]. None of the most populous cities follow the same trend as the region. The level of street-network sprawl in the aggregate network in Quezon City [Manila] rose steadily.

To date, Metropolitan Manila is the 45th-most disconnected out of the 51 regions in Philippines. Its position in the ranks since 1975 has fallen; relative to other regions in Philippines, the street network in Metropolitan Manila has become more connected. Metropolitan Manila ranked 32nd in 1975, 41st in 1976-1990, 43rd in 1991-2000 and 45th in 2001-2014.