Density is a hugely important measure that is connected to everything from urban design to transportation and economic growth.
The densest central urban neighborhoods are usually those that developed earliest before cars and trains allowed people to cover travel more than a few kilometers in an hour’s time.
The densest neighborhoods found are frequently found in Chinese cities. Even the densest parts in New York City are no less dense than the densest neighborhoods in China.
Tokyo also has the highest overall density of all the cities, and yet almost no district in Tokyo exceeds 20 thousand people/sq km (light red color).
Los Angeles and San Francisco have small, high density (red) urban cores that were developed before the appearance of the car, in contrast to more far-flung lower density suburbs which were built up mostly after the appearance of the car.
Density classification scheme:
- Light yellow: less than 1,000 people/sq km
- Dark yellow: 1,000 to 2,500 people/sq km
- Light orange: 2,500 to 5,000 people/sq km
- Dark orange: 5,000 to 10,000 people/sq km
- Light red: 10,000 to 20,000 people/sq km
- Dark red: 20,000 to 40,000 people/sq km
- Pink: more than 40,000 people/sq km
Urban Rail Transit
A minimum density of about 11,5 thousand people/sq km is required before heavy rail (subway) development makes economic reason (red and pink area on the map). The density threshold at which light rail is cost-effective is about 7 thousand people/sq km (dark orange color).
In some cities, you can see a perfect overlapping of subway systems with high-density neighborhoods (light red and above colors). This is cities with subway networks that date back about a century (Paris, New York City, Tokyo).
Other cities’ subway systems are not so strictly aligned with high density, serving both medium and high-density parts (London, Chicago, Sao Paulo).
Chinese cities rely on constantly growing subway systems to meet the same needs. This is why Beijing and Shanghai now have the longest subway systems on the planet.
Classes of urban rail transportation:
- Light rail (trams, monorails)
- Heavy rail (subway)
- Commuter rail and regular speed inter-city passenger railroads
- High-speed rail