The Jetsons had them in the 1960s. They were the defining...

The Jetsons had them in the 1960s. They were the defining element of 'Knight Rider' in the 1980s: cars that drive themselves. Self-driving cars appear in countless science fiction movies. By Hollywood standards, they are so normal we don't even notice them. But in real life, they still don't exist. What if you could buy one today?