What's the most efficient form of transportation?
A 140 lb. person walking 3 miles per hour uses about 80 food calories per hour.
The same sized bicyclist, traveling at a brisk 16 miles per hour uses 43 calories per hour.
Compare this to automobiles.
Walking: 360 mpg
Bicycling: 732 mpg
Missing from this picture: airline travel. Since the last entry was about a visit to Germany, this deserves a post of it's own ... to be continued ...
The math: One food calorie contains 4.184 kiloJules of energy (a kJ equals 1,000 (10-to-the-3rd-power) Joules). One gallon of gasoline contains 114,000 British Thermal Units (BTUs), or 120 MegaJoules (MJs) of energy (a MJ equals 1,000,000 (10-to-the-6th) Joules). Sources: http://www.exploratorium.edu/cycling/humanpower1.html; http://auto.howstuffworks.com/question527.html; http://en.wikipedia.org/wiki/Fuel_efficiency_in_transportation