Environmentally friendly car sharing services are getting more and more popular, and car sharing companies like ZipCar are quickly gaining lots of fans who are realizing they don’t need to own a car when they can share one. If you don't know how car sharing works, it couldn't be more simple... just sign up with a company like ZipCar, which is currently the most popular of the numerous car sharing services, then reserve a car online or by using your cell phone when you need to drive somewhere. After that, just head to one of their car lots, swipe your card, and you're off, driving to wherever you want for a mere 11 dollars an hour, which includes both insurance, and, you'll love this, gas mileage. And when you're done with the car for the day, you just turn it in, giving another customer the chance to get behind the wheel. ZipCar already has 180,000 members, and the company's CEO says that forty percent of their customers sell their car or halt the purchase of a new car after trying the service for the first time. ZipCar users can save tons of money by cutting costly monthly car payments from their life, and the average customer spends well below 100 bucks a month on the service. And the environmental impact of shared car services is astounding... one shared car equals six other cars being removed from the road, which really adds up considering that the average car spews out 5.5 metric tons of CO2 a year. And members of car sharing services say they use mass transit 47 percent more, walk rather than drive 26 percent more often, and hop on a bicycle 10 percent more frequently. So don't be afraid to free yourself from car ownership... you can always get behind the wheel of a shared car if you really need to drive, and you'll be doing a lot of good for the environment