4 wheel drive gives a false sense of security, as well. I remember being out in a storm on I95 between Providence & Boston. There was a car down in the median or on the side rails every 1/4 mile. Many never figure that shit out.
I lived in the NE hills. Sometimes sanders have to drive backwards. Plows and sanders would also lead school buses, too, if for some reason a storm blew in while school was in session. The buses and snow clearing rigs have automatic chains.
Only thing that will stop road clearing is masses of snow. This didn't look like that much snow. just enough to make it greasy. Accidents blocked going forward, so best bet would be to clear to the end of the back up and get cars turned around to the first exit behind them, and work your way forward. Police would have traffic flow control.
Snow pack on the road and sanded are the best roads all year if you don't have paved roads. You don't take the snow down to road, leave a couple of inches and sand it.