The cars of the future promise to be safer because sophisticated sensors and cameras will give them a far better understanding of potential dangers than any human can muster.
That technology also will let them travel with little driver intervention.
But what happens when a self-driving car can't avoid an accident?
A large truck speeding in the opposite direction suddenly veers into its lane.
Swerve left and smash into a bicyclist? Right and careen toward a family on foot? Slam the brakes and likely injure the passengers?
The relatively easy part is writing computer code that dictates how a car will react.
The bigger problem is just what that reaction should be.
So far, the people working on the technology say they haven't focused on these ethical questions.