Here's why self-driving cars may never really be self-driving

Two self-driving cars are headed down the highway when the lead car decides to speed up to avoid being rear-ended by the second. That car, in turn, slows down to avoid hitting the first. Then a third car suddenly comes between the two, prompting the slower car to change lanes to avoid and accident. The problem: There are cars in the lanes on either side of it. What's an autonomous car to do?