Americans are famously dependent on their cars.In fact, with 92% of U.S. households owning at least one vehicle, the idea of living without them can seem unrealistic and even unimaginable.But according to a recently released study by Arizona State University researchers, attitudes toward car-free living are changing, with nearly one-fifth (18%) of U.S. car owners expressing a definite interest in ditching their rides, and more than half being open to the idea.