From "Friends don't let Friends Drive"

"Here's a fine place to start. Find a local map or draw a rough draft of your local area. Using a compass (remember those from high school geometry?), draw a circle approximating a one-mile radius around your home. Draw another approximating a three-mile radius; another for five miles; and another for ten. Realize how often you travel in those near reaches of your home. Consider that most people walk at a rate of three miles per hour, and most people can easily bicycle at a rate of ten miles per hour. National statistics show that more than a quarter of car trips in this country are to a distance of one mile or less; walking this distance would take 20 minutes or less. And nearly two-thirds of our daily car trips are to a distance of five miles or less, easily less than a 30-minute bicycle ride. Annually, a typical North American car will add close to five tons of carbon dioxide to our atmosphere. Every mile driven by car adds to that toll. Consider what could be saved by walking, bicycling, car pooling, or using public transit. According to the Union of Concerned Scientists, the use of cars tops the list of the most environmentally harmful activities in which individuals engage. Cars and light trucks are responsible for about 48 percent of toxic air pollution, 25 percent of greenhouse gases, and 22 percent of toxic water pollution. Keep these numbers in mind when you get behind the wheel of a car. Post them on your dashboard."