Talking about the ethics of self driving cars is a red herring. Cars will be programmed to follow the rules of the road, no more, and no less.

Roadways and speed limits are designed to be safe. Driving at the speed limit will always give you enough time to brake to a safe stop if an obstacle appears or attempts to cross the road. Maintaining a proper distance to the car in front of them. Lowering speed in response to adverse weather. They will never have to "choose" between one outcome or the other.

If a truly exceptional situation occurs - say another car runs a red light and crosses your path - the self driving car will attempt to prevent the crash within the rules of the road. Again the car does not get to choose. The car may apply full emergency brakes, but is not allowed to change lane unless they have had the indicator on for three seconds. This rule is in place is to discourage people from recklessly swerving to avoid a minor accident and potentially causing a bigger, more fatal one.