An individual who is so clueless, reckless, stupid, or careless, that it's only a matter of time before they cause serious harm to themselves or someone around them.
Whenever you see a Toyota Corolla with it's back bumper taped together with duck tape pressed on half ass, and the front bumper straight up gone, it's a pretty safe bet that they're a ticking time bomb and they're a terrible driver who needs to be avoided at all costs.