You don't really seem to know much about modern self-driving cars.
Google already has self-driving cars driving on roads around California and Texas. Sure, both states seem rather unreal to me at times, but I'm pretty sure they count as real-world.
You don't need to deal with ANY possible situation. If a rhinoceros comes running down the road I'm driving on, I don't need to know how to deal with it; I'll just slow down, pull to the side or evade the animal, and stare at it in confusion. A self-driving car just needs to follow similar rules of thumb; "slow down, get out of the path of traffic, call for help".
The cars are not perfect; they need more practice in rain. Snow and ice challenge most humans, so that will take a bit. But they are pretty good with guys with flags and hand gestures. Unmapped signs are fine; do you really think they have a trusted list of all signs? No, that's why they have cameras. Don't need perfect maps, though better maps are always a plus. As I said, you don't seem to know much about the technology, and I encourage you to learn more about it before loudly asserting things which are untrue.
They already drive better than humans (though in a slightly more narrow set of circumstances); that's a really easy bar to beat because humans are terrible drivers.