We are always on about how efficient bicycles are as a means of mobility. See our early Eco-Tip on the topic. More recently the WorldWatch Institute published some intriguing figures on cycling. Comparing energy used per passenger-mile (calories), they found that a bicycle needed only 35 calories, whereas a car expended a whopping 1,860. Bus and trains fell about midway between, and walking still took 3 times as many calories as riding a bike the same distance. They also looked at a measurement called: 'Persons per hour that one meter-width-equivalent right-of-way can carry'. In this case Rail scored tops with 4,000 persons, but 'autos in mixed traffic' still managed the worse rating with only 170 people. Bikes did pretty well, relative to cars, achieving 1,500 persons per hour. This is the sort of impact that Critical Mass rides around the planet try to demonstrate on a regular basis. The stats also inferred that cycling contributes to a nation's health. For example, they found that only 1% of urban travel in the US was by bicycle, a country with 30.6% of adults considered obese. This contrasted with the Netherlands where 28% of urban travel was via a bike, and only 10% were obese. More at WorldWatch Matters of Scale.