SUVs for Safety Reasons

My wife knows a woman, older but with no kids and no husband. She drives a huge SUV because she thinks it's safer. Not because she needs the SUV. Sure, an SUV vs. say, my wife's Echo ... the SUV wins. But how about being a safe driver? Or should we all drive Hummers and get less than 10 miles per gallon? This really Grinds My Gears.