The hustle and bustle of city streets may seem like a random and chaotic movement of people, but researchers have discovered that this movement can in fact be predicted with a mathematical equation─a discovery that could hold implications for the study of disease and city planning.
The model was created using data from eight million people between 2006 and 2013 from six urban locations around the US, Singapore, Portugal, Senegal, and Ivory Coast. Using anonymized cell phone data, the researchers noticed some distinct patterns regardless of location or demographic. They found that human movement can be modeled because all humans fundamentally seek to optimize their day. Whether dropping kids off at school, going to the grocery store, or visiting distant relatives, lead study author Markus Schläpfer explains, “At the core is the effort that people are willing to invest collectively to travel to certain locations.”
The equation is based on the inverse square relation between the number of people in a given urban location and the distance they traveled to get there, as well as how often they travel there.
Creating a mathematical law to model human movement is useful not only for creating more efficient public services and transportation systems, but also for managing disease─like a global pandemic.
Epidemiologists can predict disease spread from city to city based on the region’s population size, but understanding movement dynamics within a city will allow for this pandemic and future ones to be better managed on a micro scale. Essentially, within a large city with many people, populations can experience the same infection spread patterns as a county or even state would experience, just more condensed.
It is also intriguing that despite different transportation options, city sizes, cultural values, or economic trends, humans tend to move through the world following the same general pattern. There is something comforting about the fact that regardless of place or purpose, the same sense of space and time moves us through our cities. Want to learn more? You can check out the visual model of the equation here.
Source study: Nature – The universal visitation law of human mobility