Based on human history I can pretty much assure everyone that every problem we have imagined, and more, have long since been imagined by the people who ALREADY HAVE WORKING AI CARS ON THE ROAD, and have for hundreds of thousands of miles.
Pretty long way to bashing something with a rock to being able to open a person's chest, remove the heart, and replace it with another. Think maybe there were a few issues to resolve? Nowadays we have surgeons operating remotely via the internet. No biggie.
We seem not to grasp the things we have proven able to do.
As one poster noted, we are using tiny computers made by many different corporations over a span of years and all able to communicate, surf the web (Just think about that---we could never have a billion different computers in a hundred different languages if two hundred different countries all communicate---while in cars" we say while using our cell phones to do just that ... to such a degree that it as actually a hazard we all complain about. Cognizant disconnect, much?)
Are there problems? Difficulties and unresolved issue, to be sure. Is it complicated? People wouldn't be spending billions and years io it if it were simple.
But based on what we have done in just the past few years --DONE--not imagined or are aware of or denied---as Walter notes, the main problems are commercial and social.
People either want, or don't want, or are neutral regarding AI cars .... and all these tens of thousands of words wasted in a supposed 'examination" of the topic is really just a poll with A,B, or C.