How do you expect human remote control to work reliably enough for safety critical situations when our existing cellular data network fails so frequently? What happens when a construction crew accidentally cuts through the backhaul fiber?
The handover will be after the car stops because it’s confused. If there is no cell network or no operator available the car is simply stranded on the side of the road, just as after a mechanical failure. Operators can’t help “unknown situations” while moving.
In many places like bridges, hills, and congested city streets there is literally no road shoulder, no safe place to stop. When existing cars break down in those locations they end up blocking a traffic lane and frequently get hit from the rear by a drunk or distracted driver.
Yes, the autonomous car will need to make a judgement whether to “limp” out of a situation it is unsure of, or whether to stay where it is. It’s weighing two risks against each other). This happens whether it’s 95 or 99.99% autonomous - it just happens with different frequency.
It could also be possible for the occupants of the car (if it has any!) to pick up a smartphone and guide the car to safety if needed. Part of the attraction of autonomous vehicles is that if can operate without occupants, however.
I had to drive once on a punctured tire that was deflating. No shoulders due to construction, and in fact I had to speed through the work zone to make sure I got to an exit while I still had some air.
The real world is a very very messy place.
I think when cars are 95 or 99% autonomous they will be sold with human remote control so there will be centers where manufacturers have hundreds of remote drives ready to intervene and handle the last 5% or 1% of situations. Ther race to AV profitability will be won by the manufacturer with the smallest army of backup drivers.