For example, when we
compare two cities of different population sizes in the same urban system (usually a
nation) we tend to find that the larger is a little bit denser, and that its volume of
infrastructure networks per capita (roads, pipes, cables) is smaller. We also find that
the larger city is usually wealthier (as measured by its per capita GDP or wages),
more expensive and more productive culturally and technologically, e.g. in terms of
numbers of creative endeavors or patents filed. Thus, these measurements confirm
general familiar expectations that larger cities are not only more congested and
expensive, but also more productive and exciting culturally.
These effects are universal, in the sense that they are observed across cities in many
urban systems, from the US to China, and from Brazil to Germany (4,5). They also
apply over time, in contemporary urban systems, as well as in the spatial patterns of
settlement of Pre-Hispanic Basin of Mexico measured over a 2,000 year period,
which must have evolved independently from their old world counterparts (32).