That is the new and excellent book by Alain Bertaud, so many pages have excellent food for thought. Here is one simple bit:
Cities are primarily labor markets.
…large cities are growing at about the same rate as medium and small cities in the same countries or regions. It seems that cities’ growth rates follow Gibrat’s law of proportionate effect, which states that the size of a city is not an indicator of its future growth rate — that is, cities’ growth rates are random, with the same average expected growth rate and same variance…The population of larger cities keeps growing, but on average, so do smaller cities. This seems paradoxical, given that larger cities are more productive than smaller ones. However, larger cities do not play the same economic role as smaller ones do. They complement each other’s activities. The increase productivity of larger cities is therefore linked to the existence and growth of smaller cities. In turn, smaller cities’ economic growth is dependent on larger cities’ innovations and inventions.
How about this:
In 1830…London’s population density had reached a very high density of 325 people per hectare. By 2005, however, the density of London had decreased to only 44 people per hectare. The larger decrease in London’s density has not caused a corresponding decrease in mobility. On the contrary…
I learned a great deal from the discussion (starts p.287) of Indonesia’s “kampungs,” and how the Indonesian has managed their integration with local infrastructure relatively well. In contrast, this is the common alternative procedure:
The predictable first reaction of governments has usually been to set minimum urbanization standards to prevent the legal construction of these unsanitary urban villages. The regulations made the situation worse, as they prevented these informal settlements from obtaining normal urban services from the municipality. They also created a risk of future demolition, which discourages housing improvement that the households would have naturally done themselves. Eventually, many governments slowly regularized the older informal settlements in a piecemeal fashion, as is the practice in India, for instance. But the regularization of informal settlements usually had been conducted with a provision that after a set date, no more informal settlements would be regularized.
The outcomes of these successive policies — first ostracism, then benign neglect followed by reluctant integration — has been disastrous. A significant share of the urban labor force, otherwise gainfully employed, live in large “informal” settlements often with unsafe water supplies, deficient sanitation, and sporadic solid waste collection.
What made a difference [in Indonesia] was a decision taken in 1969 by the government of Indonesia to concentrate its resources on the improvement of the kampungs’ infrastructure without trying to remove or restructure the existing housing, however small or inadequate it was…And, even more exceptional, since 1969 to this day, the Indonesian government’s support for KIP has been unwavering…The government housing policy objective consists of allowing the poor to settle in and around existing villages at the standards of their choice, while the government concentrates its efforts not on housing construction but on gradually improving residential infrastructure and services to all residential settlements. The policy has proved largely successful.
Later in the book, pp.351-352 have a fascinating discussion of how relatively good urban/suburban policy, and also the fragmentation of municipalities, contributed to the early success of the tech community in Silicon Valley.