The Physical and Biological Laws of Cities
Like veins that form the network transporting blood through our bodies, roads and electric lines transport energy and resources through cities. As people and companies share the desire to move from point A to point B as cheaply and quickly as possible, city systems evolve to become more efficient, thanks to continuous feedback mechanisms. However, communities still must utilize resources within the constraints of availability.
Some laws in the realms of systems and networking and just plain selling can help us understand where people are ‘going’ and provide a framework for understanding, and even predicting, how customers in cities who are constantly bombarded with new products and technologies will adopt them.
Geoffrey West’s Law of Urban Scaling suggests, “that essential properties of cities in terms of their infrastructure and socio-economics are functions of their population size in a way that is scale invariant and that these scale transformations are common to all urban systems.” In simple terms; cities follow a predictive model based on population size, and as a city grows it benefits from economies of scale. For example, the bigger the city, the fewer the number of gas stations needed on a per capita basis. A gas station in a larger city serves more people and sells more fuel/month on average than in a smaller city. With each doubling of population size, a city needs 85% more gas stations, instead of double the number. This economy of city scale applies in every city and country in the world. The interconnectedness among all elements that comprise a city make it a complex adaptive system – a network – bringing us to the second law.
Metcalfe’s Law states that a network’s impact is the square of the number of nodes in the network. If a network has 10 nodes, its inherent value is 100 (10*10), suggesting that as the amount of people and networked infrastructure grows in a city, the value the city derives from them grows exponentially. But only if the links between the nodes are present.
Large retail stores and centers, 200k feet, require about half a million households within a twenty minute drive (Link: Walmart: A History of Sam Walton's Retail Phenomenon, Vance & Scott). Considering Scale Laws above, a smaller retail outlet or business within the same sector in a city, that is dependent on foot traffic, would require the an equivalent scale law ratio to ensure it operates successfully.
Why do we need to understand these laws (and the list above is far from exhaustive)? Because only then will we take actions and focus our attention on building our cities respecting these laws. To ignore the laws is to doom our cities to failure. And we do not want that at all.