People travel for many reasons—commuting, as part of their job, or to go shopping—and the time spent traveling differs from day to day, from person to person. But remarkably, populations tend to travel for close to 1.3 hours per day (78 minutes), no matter where they live, or how rich they are. This is shown by a new international study from the Institute of Environmental Science and Technology at the Universitat Autònoma de Barcelona (ICTA-UAB) and the McGill University in Canada, which concludes that the key to reducing energy consumption at population level lies in designing communities that encourage low rates of energy use during those 78 minutes of daily travel.

Although technological advances have made vehicles more efficient, global energy consumption in transport continues to rise. The study, recently published in the scientific journal Environmental Research Letters, suggests that the energy used per hour of travel — rather than per kilometer traveled — is the real factor that will determine future energy consumption.

The analysis is based on data from personal and work-related travel in 43 countries, representing more than half of the world’s population. The results confirm previous indications that societies tend to stabilize their total daily travel time at around 1.3 hours (78 minutes) per day, with a variability of 0.2 hours (12 minutes). In other words, populations spend, on average, between 66 and 90 minutes a day traveling from one place to another, regardless of the mode of transport or the distance covered. This “convergent” range of travel time does not depend on whether people are walking, biking, or driving, and appears to come from deep-rooted psychological desires to see the surroundings, combined with practical limits that prevent people from spending too much time traveling.

“The most important finding is that people don’t travel less when speed or efficiency increases; instead, they travel farther,” explains the study’s corresponding author, Eric Galbraith.

Researchers argue that this convergence of travel time provides a robust tool for predicting how societies will respond to technological changes or public transport policies, even if these involve complex behavioral changes. Since total travel time remains constant, the behavioral changes will end up altering how that time is distributed among different modes of transport—and with it, energy expenditure.

For example, a city organized around light rail, where each person spends about 40 minutes a day on the train and walks the rest of the time, will predictably consume about five times more energy than a city where all travel is on foot. And a city based on combustion-engine cars can use up to 100 times more energy per person than a pedestrian city, even if vehicles are relatively efficient per kilometer traveled.

The study emphasizes that policymakers and urban planners play an essential role in reducing energy consumption in transport: by promoting travel modes with low energy use per hour, such as walking, cycling, or electric public transport.

“Since total travel time is nearly constant,” says coauthor William Fajzel, a PhD student at McGill University, “policies that enable people to choose low-energy-per-hour modes of transport will be the most effective for reducing transport energy demand.”