Most people can't go out tomorrow and trade in their car, but you can pledge to make your next car the most fuel-efficient in its class. Buying smart can double your fuel efficiency. What car should you choose? There's a couple of things to know:

First, it's widely known that the EPA mileage ratings are inflated (they're based on out-dated assumptions). Consumer Reports has done its own extensive testing, and their results are freely available on the Greener Choices auto ratings site.

Second, you should also know about alternative vehicles that are not yet as mainstream as Toyotas and Hondas. Vehicles such as the SmartCar and the Sparrow are coming on the market, which are even more efficient. We need more info on these here!