What Can the the Trolley Problem Teach Self-Driving Car Engineers?

OK, tell me if you've heard this one before. A trolley, a diverging track, a fat man, a crowd, a broken brake. Let the trolley continue to speed the way it's going, and it will smash into the crowd, obliterating the people in its way. Hit the switch, and the trolley will careen into the fat man, KOing him--permanently--on impact. That is, of course, the classic trolley problem, devised in 1967 by the philosopher Philippa Foot.