People organize daily travel efficiently

A population-level study discovers small-scale details about individuals' choices. Studies of human mobility usually focus on either the small scale - determining the origins, destinations and travel modes of individuals' daily commutes - or the very large scale, such as using air-travel patterns to track the spread of epidemics over time. The large-scale studies, most of which are made possible by the vast data generated and collected by new technologies like sensors and cellphones, are very good at describing the big picture, but don't provide much detail at the individual level. Smaller-scale studies have the opposite characteristic: Their findings generally can't be scaled up from the individual to be applied broadly to populations. But a new study led by MIT's Marta González bridges that gap. It uses big data and the methodologies of statistical physics and network theory to describe the daily travel behavior of individuals, behavior that holds true at the larger scale of the entire population of two cities on different continents. The study, published in the May 8 issue of the Journal of the Royal Society Interface , shows that people in Chicago and Paris make their secondary trips - those in addition to their primary commutes - in a consistent and expeditious manner, using only 17 of more than 1 million possible trip sequences for up to five secondary locations.