SUVs and fuel economy haven't always gone hand in hand. In fact, SUVs have pretty much always been known as gas hogs.  So when my best friend told me that she was trying to find the best gas mileage SUV, I was somewhat surprised.

It didn't seem to make much sense. When you buy an SUV, you're giving the world a message: luxury matters more to me than economy or fuel efficiency. Of course there are certain car companies such as Subaru or Saturn which specifically market to yuppies and other supposedly environmentally conscious folks, but even these are not known for being tremendously energy-efficient. Still, I was intrigued. I wanted to find out more about the fuel efficient SUVs.

The real problem is that the SUV category is fairly flexible. Although they're supposed to be rugged vehicles equipped for off-road driving, the reality is much different. Many of them are simply status symbols designed for people who like to show off.

They're usually pretty roomy inside, sit high off the ground, and are large enough so that if you get in a crash, the other car takes the worst of it. That isn't to say that all SUVs are safe. Even the toughest vehicle might not save you from a rollover crash, and that can be fatal. Nowadays, many of the design flaws inherent in sport utility vehicles are being corrected, but I still wouldn't trust one with my life without doing a lot of research.

You can do your research and get expert car ratings at Consumer Reports or at JDPower Autos.

The biggest problem with his research, of course, was coming up with a definition for what an SUV really is. A car like the Saturn Outlook, for example, might be considered an SUV but might not. Would a crossover car qualify for the best gas mileage SUV? It's sometimes hard to tell, and my friend couldn't decide.

In many ways his project was a waste of time, but it did have one good effect. Researching the best gas mileage SUV really got him thinking. For the amount of money that he would spend buying a new SUV, he could get something that was really fuel-efficient such as a Honda hybrid car.

He finally came to the conclusion that he didn't really need an SUV. He didn't have a whole lot to haul around, and he rarely, if ever went off-road. Instead, he invested his money in a fuel-efficient car. It might not be as big and overbearing, but it will save him a lot of money in the long run.