For instance, should your robot car kill you to save the life of another in an unavoidable crash?

Consider this thought experiment: you are travelling along a single-lane mountain road in an autonomous car that is fast approaching a narrow tunnel. Just before entering the tunnel a child attempts to run across the road but trips in the centre of the lane, effectively blocking the entrance to the tunnel. The car has but two options: hit and kill the child, or swerve into the wall on either side of the tunnel, thus killing you.

Both outcomes will certainly result in harm, and from an ethical perspective there is no “correct” answer to this dilemma. The tunnel problem serves as a good thought experiment precisely because it is difficult to answer.

The tunnel problem also points to imminent design challenges that must be addressed, in that it raises the following question: how should we program autonomous cars to react in difficult ethical situations? However, a more interesting question is: who should decide how the car reacts in difficult ethical situations?