Limitations...... Technology has Limitations ???
Excellent points..... I've driven snow covered roads with almost no forms of visual reference - not easy, even for a skilled Winter driver - a machine-based vision system would have a very tough time. GPS and cell coverage are just not consistently accurate enough to cover all of this continent, all of the time (in terms of being the primary reference, when vision inputs are minimal).
Your comment had me thinking about highway emergencies/shutdowns. Restricted by geography, sometimes there is only one road, so when you're stuck, you're stuck. But, if a major highway shuts down, sometimes there are tiny secondary rural roads as alternates - as a former long distance commuter, I've done that dance many a time....
I'm aware of engineering testing done on high speed autonomous convoys - the tech is there, but given the reality of limited EMS and road budgets, I can't see that being accomplished with thousands of now-blind driverless cars coming off a major highway.
Rgds, D.
