My skepticism has to do with the following:

* People talk about how automatic cars have been extensively tested. That's not really true. There's only a handful of them on the roads and they've been tested in limited conditions, with particular limits placed on suburban driving (slow speeds, etc.). I suspect there will be entirely new classes of bugs when there are hundreds of different AIs competing on the road, especially when mixed with normal human traffic.

* LIDAR does not work in poor weather conditions, including ice on the road.

* In terms of AI, getting to the 90% point is relatively easy, but it seems like the last 10% would require something resembling true intelligence. How do you deal with a lack of markers on the road? Dangerous situations in shady areas? Sensor equipment getting damaged and feeding your car wrong information? Animals and children running out last-second into the road? Severe obstacles at a distance? Tiny, cramped residential roads with non-sidewalk pedestrian traffic? Accommodating emergency vehicles and police? We shut off our brains when driving 90% of the time, but that last 10% does require human levels of intelligence. Furthermore, unless every car on the road is automated, the AI in automatic cars will need to deal with the idiosyncrasies of other human drivers. Sudden merges. Speeding. Road rage. Unexpected emergencies. Tailgating. An AI can't send and receive feedback to other human drivers and pedestrians; it can only use its model of human behavior to predict likely outcomes. (And this is saying nothing of other AIs on the road, who might behave completely unlike human drivers.)

* People say that automated cars only need to drive better than human drivers, not perfectly. I don't know if that's true. If automated cars drove perfectly 99.9999% of the time but then crashed horribly that remaining 0.0001% — taking some poor pedestrians or bicyclists along with them — I wouldn't get into one. And I don't think they'd be street-legal. Most people don't want to think about human lives in terms of numbers; they'd rather have control over their actions and accept the inevitability of occasional accidents, rather than having a machine that's practically guaranteed to eat up human lives every so often.

* Speaking of which, how does the car decide who gets to live in a life-or-death situation? Are there situations where the car would elect to kill the driver? Which programmer gets to make that decision? I'd like to know this information before getting into my car, please. The idea of offloading split-second moral decisions to an AI seems like it should be severely legislated.

* People talk about mesh networking improving traffic and whatnot. I can't even get my USB devices to work across OSes half the time, and we're talking about sophisticated traffic control across multiple manufacturers? Especially given the quality of software that car companies tend to put out?

* Self-driving technology is extremely expensive, and most cars on the road are pretty cheap. You'd have to have some sort of insane subsidy program to get more than the 1% driving automated cars.

* People want to get in their self-driving cars drunk, but I think there will be severe legal hurdles in the way of that.

I think semi-automated and AI-augmented driving are certainly possible. Highways are easy enough to tackle. I could see some expensive cars getting that capability over the next few decades, as well as maybe cargo trucks. But endpoint to endpoint driving, where you could snooze on your way to work? I don't think so.