I think we need to step back a bit here.
The BBC article was not definitive as to the condition of the road.
Was it icy all over? Or was the ice confined to the odd patch?
If the road was icy all over, the cyclists and the driver exercised
poor judgement. Cycling on ice is a bad idea, if you don't have to do
so. Driving at 50 MPH on ice is also a bad idea as control is hard to
maintain and easily lost.
If there were only patches of ice, you could suggest that the driver
ought to have been more attentive, but even that is iffy. Depending on
how many patches of ice there were, etc, the driver may legitimately
have been taken by surprise (a kink in the road, in the shade, so that
the ice had not melted there while it had melted everywhere else).
Jeff