David Weinberger:

1. The programmed morality of networked cars
 Google self-driving cars are presumably programmed to protect their passengers. So, when a traffic situation gets nasty, the car you’re in will take all the defensive actions it can to keep you safe.
 But what will robot cars be programmed to do when there’s lots of them on the roads, and they’re networked with one another?
 We know what we as individuals would like. My car should take as its Prime Directive: “Prevent my passengers from coming to harm.” But when the cars are networked, their Prime Directive well might be: “Minimize the amount of harm to humans overall.” And such a directive can lead a particular car to sacrifice its humans in order to keep the total carnage down. Asimov’s Three Rules of Robotics don’t provide enough guidance when the robots are in constant and instantaneous contact and have fragile human beings inside of them.
 It’s easy to imagine cases. For example, a human unexpectedly darts into a busy street. The self-driving cars around it rapidly communicate and algorithmically devise a plan that saves the pedestrian at the price of causing two cars to engage in a Force 1 fender-bender and three cars to endure Force 2 minor collisions…but only if the car I happen to be in intentionally drives itself into a concrete piling, with a 95% chance of killing me. All other plans result in worse outcomes, where “worse” refers to some scale that weighs monetary damages, human injuries, and human deaths.