Patick Lin considers some of them in a piece in Wired, starting with the trolley problem - whether a person who has control of a runaway trolley should let it kill five people tied to the track without intervention, or should pull a lever so that only one person on another track is killed. From there, he wonders about the possibility of fixed ethics settings, created by manufacturers, versus user-adjustable ethics settings that, for example, allow a driver to prioritize his own safety over others, or prioritize the safety of children over that of the elderly.
Lin admits that the examples are outrageous in order to stress the point of the question. Still, it's worth a read because we already have cars that can make driving decisions, and it might not be long before "Five-Mode Adjustable Prime Directive" shows up on the options sheet. Head over to Wired to read the full piece.