Death by robot

Let’s say the only way the car can avoid a collision with another car is by hitting a pedestrian. “That’s an ethical decision of what you do there, and it will vary each time it happens,” he says. Is the pedestrian a child? Is the alternative to swerve away from the child and into an S.U.V.? What if the S.U.V. has just one occupant? What if it has six? This kind of reasoning is what the philosopher Patrick Lin, director of the Ethics and Emerging Sciences Group at Cal Poly, calls “moral math.” It evokes the classic Ethics 101 situation known as the trolley problem: deciding whether a conductor should flip a switch that will kill one person to avoid a crash in which five would otherwise die.

Here’s the difficulty, and it is something unique to a driverless car: If the decision-making algorithm were to always choose the option in which the fewest people die, the car might avoid another car carrying two passengers by running off the road and risking killing just one passenger: its own. Or it might choose to hit a Volvo instead of a Mini Cooper because its occupants are more likely to survive a crash, which means choosing the vehicle that is more dangerous for its owner to plow into. These assessments can be made with lightning speed. The car records data using lasers, radar and cameras mounted on its roof and windshield, and it makes rapid probabilistic predictions based on what the observed objects have been doing. But this is less an engineering question than a philosophical one, which the makers of such a car will have to resolve and, you would assume, bear some legal responsibility for.