One could blow out while you're driving, or you might begin to feel an immense vibration every time you get behind the wheel. Shopping for a mattress is a pain in the ass; Modern mattresses are manufactured in an array of standard sizes. Mercedes is bringing a bigger, bloated version of its smart car to the united states. It’s expensive, after all, and it’s hard to distinguish one mattress from another when they look identical, except for the fact that one might be a few inches longer or wider.