Ed Glaeser, Giacomo Ponzetto, and Yimei Zou recently published a new academic paper called, Urban Networks: Spreading the Flow of Goods, People and Ideas.
The paper looks at whether it’s more advantageous to build huge and consolidated mega-cities or build connected networks of smaller urban centers (perhaps connected by high speed rail). As countries like China rapidly urbanize, this is something that many people are thinking about.
In China, there is a lively urban planning debate
about whether to facilitate the increased expansion of the vast agglomerations of Beijing and
Shanghai or whether to focus on creating networks of cities that are smaller, albeit still much
larger than almost all of the cities of Western Europe. The current government policy favors
networks, in the hope that connected smaller cities may be free of the extreme downsides of
mass agglomeration, such as extreme congestion, pollution and high housing costs.
Like most things, there are real trade-offs.
In the paper, they assume that larger cities lead to more urban amenities, which in turn serves as an important magnet for skilled workers. However, for unskilled workers who may not care/benefit from the same urban amenities, it is possible for them to dislike the bigger cities. In this case, the benefits do not outweigh the negatives of urban expansion and an urban divide is created (rich/poor).
One of the potential negatives is housing.
The attraction of denser, not larger, mega-cities is determined also by the elasticity of
housing supply. When it is easy to add extra homes on a narrow plot of land, as in Texas,
then density becomes more attractive. European urban networks may well be the right
answer because history and regulation makes it so hard to build in Europe’s older cities.
Even though China has usually been quite friendly towards skyscrapers, the sheer scale of
the Chinese population may still make the case for urban networks.
If you’re interested in this topic, there’s a section (#2) in the paper on the history of urban networks that you might like.