Passenger vehicles account for 62 percent of all greenhouse gas emissions in the U.S. The average vehicle spews out more than 8,000 pounds of CO2 each year for every 12,000 miles it travels. While the future is looking bright for increased efficiency vehicles, right now it is hard to beat a hybrid Toyota Prius at 46 mpg. And if you think that an economical vehicle like the Prius will be roughing it, you really have not been for a ride in one recently. We are talking about such amenities as smart entry and push-button start (unlock and start vehicle without using key), DVD-based navigation, back-up camera, premium audio in-dash entertainment center (9-speakers), 4-way adjustable bucket seats, automatic air conditioning, rear adjustable headrests, power door locks and windows, and tilt steering. All this, and they start at around $6,000 for a used 2001 model. Not all the above mentioned amenities were around in the earlier models, but the used Prius still can achieve over 45 mpg with practically one tire tied behind its trunk!