The ethical dilemmas of the driverless car

We make decisions every day based on risk – perhaps running across a road to catch a bus if the road is quiet, but not if it's busy. Sometimes these decisions must be made in an instant, in the face of dire circumstances: a child runs out in front of your car, but there are other dangers to either side, say a cat and a cliff. How do you decide? Do you risk your own safety to protect that of others?