I have just been reading in a book called "The Bottomless Well" that driving around in a big f***-off SUV is actually more environmentally friendly than cycling. It says, "Yet however preposterous the idea may sound, drilling for oil and building an SUV-grade highway system uses 10 times less land, per mile and per useful pound moved, than growing food to fuel a bicyclist. The SUV starts out 300 times worse than the bike - because it moves 30 times the weight of the its driver in steel, and because it needs 10 times more road-way per useful pound moved. In terms of land surface occupied to extract and deliver the energy used, however, crude oil is at least 1,000 times more frugal than grain. And a car engine, and the refining and distribution systems behind it, are about twice as efficient in converting crude oil to locomotion than the grain-bread-muscle systems that stand between plants and pedals on a bike; make that 16 times as efficient if the biker favors meat." Hmm, I'm not sure I buy that.