Google cars recognize pedestrians (of all sizes) and regularly notice them even when no human could. I'm sure the car would choose to hit another vehicle over a pedestrian or cyclist.
For a self driving car I am not sure a choice needs to be made. Most of the difficulty in stopping on time is the reaction time. With perfect reaction time, the car should be able to stop.
How many Bavarian Illuminati does it take to screw in a lightbulb? Three: one to screw it in, and one to confuse the issue.