A self-driving car would be handy in situations where you are alone and injured, with the capacity to get to your car but not to drive safely. Severe illness, power tool accident, bear attack on a camping trip. You just get in your car and say, "Take me to the emergency room." It would actually be faster than an ambulance that had to make a round trip.

Also, pretty much the last person we (as a society) want speeding is a tired, stressed, freaking-out, distracted, soon-to-be-husband.