We just wrote about hypermiling and mentioned that one of the tips to improve gas mileage was making sure your tires are properly inflated. Well, we weren't kidding. A study done by Bridgestone Europe found that 93.5% of cars in the European Union have under-inflated tires. "Softer tires increase rolling resistance, forcing the engine to work harder - and burn more fuel. The U.S. Department of Transportation says being down just 5 to 7 pounds per square inch can decrease fuel economy by two to three miles per gallon."
It all adds up to quite a big waste. Pretty disgusting, in fact, considering that inflating tires is the closest thing you can get to a free lunch. Bridgestone calculated the extra fuel burned to amount to 2.14 billion gallons per year, and 18.4 million tons of extra CO2. Just for Europe. Wired did some back of the envelope math and found that the numbers for the whole planet are "42.32 million tons of carbon dioxide generated by under-inflated tires, or slightly less than Connecticut emitted in 2005." So check your tire pressure, and tell your friends about it! It's also important for your safety (better handling). ::Bridgestone Europe, ::We Can Cut Global CO2 By 42M Tons For Free