Dr. Mike Walden, North Carolina Cooperative Extension economist in the College of Agriculture and Life Sciences at N.C. State University, responds:

"Certainly if you could sell your big vehicle that gets low miles per gallon and purchase a smaller one at a lower price or with lower payments, and then that smaller one uses less gas that's going to be a win-win. But here's the situation many people would face: they'd have to sell their big vehicle, and right now prices on those are very depressed. You're not going to get a lot of money for it. You're going to have to go out and get, perhaps, a new vehicle, and those new vehicles, even though they're small, may carry a bigger price tag. So you're going to have to pay more money up front, or your monthly payments are going to be larger. So then it really is an investment decision. Is it better for you to pay more now in order to save money on your fuel costs down the road? Now, if you're looking at a monthly payment situation, it's very easy to calculate. Look at how much more - if you have to buy a new car - how much more in monthly payments you're going to have to make. Compare that to the fuel savings. And if you're not saving anything - that is, if the fuel savings don't counter balance the extra monthly payments - then, of course, it's a no-brainer. You wouldn't want to buy that smaller car that gets better gas mileage. So this is the kind of thing that you have to do. You just don't want to go by your gut and say, Oh, I'm going to get a small car, and I'm going to save money on fuel. Saving money on fuel is fine, but you have to consider the carrying cost, the ownership cost of that new vehicle in order to determine if it's really a net plus for you."