What type of potential energy exist if one is in a car, no seat belt on, moving at 100 mph?

Energy is not a physical unit. It is a philosophical concept and an accounting technique used to analyze mechanical and chemical exchanges. In nuclear physics it is defined as a color of light, in biology it is a synonym for metabolism, and in public utilities they say energy when they mean connectivity. You need to go back and study the subject again until you figure out why your question is meaningless.