Humans & Bikes: The Most Energy-Efficient Transportation on Earth

The most efficient way for a human to travel, measured by calories expended per distance covered, is riding a bicycle. This conclusion, recently reaffirmed by a report in Scientific American, builds on research dating back to the bicycle’s development in the 1880s.

The efficiency stems from the bicycle’s ability to minimize the two primary energy costs of travel: overcoming gravity and generating forward motion. A bicycle’s design places the rider in a seated position, reducing the impact of gravity, and transmits leg power to wheels and bearings, minimizing friction. The ability to coast, unavailable to unassisted locomotion, further enhances efficiency.

“They [bicycles] turn humans into this hyper-efficient terrestrial locomotor because they make being on land more like swimming,” explained Tyson Hedrick, a comparative physiologist at the University of North Carolina at Chapel Hill, in the Scientific American report.

Further gains in efficiency can be achieved by enclosing the bicycle within an aerodynamic shell, creating a velomobile. This design reduces wind resistance, mimicking the efficiency of aquatic locomotion.

The bicycle’s inherent efficiency has been continually improved since its initial design in 1885. Modern advancements, including improved gearing, lighter materials, narrower tires, and low-drag bearings, have all contributed to increased smoothness and efficiency. Innovations like Works By Design gearing aim to optimize power transfer by aligning with the natural up-and-down motion of the legs, which are more efficient than rotational movements.

The integration of electric assist technology, or e-bikes, further enhances efficiency. Combining human power with a small electric motor can result in greater overall efficiency than human power alone. Battery technology improvements over the past two decades have driven this development, potentially encouraging a shift away from automobiles for shorter trips.

A recumbent velomobile, coupled with a small e-bike assist motor, represents a current apex of human-powered transportation efficiency. Such a vehicle offers not only efficiency but also increased speed and enjoyment compared to traditional bicycles.