Energy intensity of human transportation

Humans are a mobile species, and transportation technology has been one of the primary enablers of our current shared, globally-connected society. Transportation is also one of the largest categories of human energy use, and this energy use correlates with a diverse range of environmental impacts. Different modes of transportation have different energy intensities, with increasing speed being associated with greater energy intensity. This study reviews the fundamental relationships and energy requirements of human-powered and wheeled ground transportation. Relevant data for modeling energy efficiency of walked, running and wheeled transport in the context of engineering design are compiled and presented. It is shown that increasing energy intensity facilitates greater speed and movement of more people. In general, people are able to travel anywhere at any speed, if they are willing and able to pay the energy price. At the same time, a willingness to accept reduced speeds would greatly reduce the energy intensity and environmental impact of transportation. Finally, several design implications for low energy ground transportation are examined in the context of energy efficiency