“Premeditated” in the context of homicide means someone intended to kill someone else. That is, they set into motion a course of actions because they believed that course of action would result in the death of a person.

Homicide in the context of fatigue or impairment are not usually premeditated because people generally do not put themselves in those cognitive states believing that doing so will result in the death of someone else.

Historically judicial systems have recognized that those cognitive states are more likely to result in unintentional deaths so do hold people operating vehicles under those conditions to a higher standard of punishment than, say, a sober person involved in a fatal crash. At the same time they consider intent and hold people in those circumstances to a lower standard of punishment than those who actually intended to kill someone.