I know this. I rode in one this week. I saw the car's human operator take his hands from the wheel and the computer assume control. "Autodriving," said a woman's voice, and just like that, the car was operating autonomously, changing lanes, obeying traffic lights, monitoring cyclists and pedestrians, making lefts. Even the way the car accelerated out of turns felt right.
It works so well that it is, as The New York Times' John Markoff put it, "boring." The implications, however, are breathtaking.
Shit, I've been following the whole self-driving car buzz from the start and I didn't know it relied so heavily on pre-registered data. Disappointing, really. It's like finding out your favourite band actually playbacks at concerts. How typical of Google, really: can't solve a problem? Throw big data at it until it works.
I was under the assumption that it scanned, processed and calculated everything in real-time - which is what you ultimately need. You don't want to be dependant on an external source. Imagine if, due to some technical problem, your car loses access to that data, while you're traveling at 120 km/h. What happens then? Besides, their data is outdated the second it is created.
I read earlier that when roadworks are happening, the car can't cope with it. Now I know why - it's not that it is a much more complex situation, but because the car isn't capable of doing so.