Not making a choice is a choice as well. But what if the computer has two options: -Keep driving ahead and kill x pedestrians. ('do nothing') -Steer the car into the nearest tree and kill y passengers. All other possibilities have been evaluated and determined to be physically impossible. (speed too high, braking distance too short, trees on both sides of the road, etc) What should the computer do when there is no 'do nothing'? If the decision of who is killed cannot be made by a computer then it must be escalated to a human. But to which human? -The passengers? -The pedestrians? Both have a personal interest in the decision so neither can be trusted to be fair. Maybe the decision should be deferred to an impartial referee? The computer could warn a government official, present him with all relevant data and then let him make a choice. Or make the decision through a democratic process. Ask a large number of responsible citizens what action hould be taken and then take the most popular course of action. This can be done with modern technology. Just get a notification on your smartphone with a small animation of each option and then tap the one you favor. You could even disguise it as a game.