Hi Wasyl, yes you're right, we are adjacent to the road on a bend and on the outside of the curve at that.
We have sustained this kind of thing on a few occasions, most drive off leaving the mess. In this instance it was simply that they had driven off the cleared area and into the snow at the verge in an effort to make room for a passing vehicle. I did the self same thing last winter but as I had moderated my speed, the results were far less devastating and the damage easily rectifiable.
The reason I install these panels is because they are easily replaced but in this instance I am now considering a brick wall... a very substantial one. It may get damaged and be more difficult and expensive to repair, but at least there is a good chance the cars won't be in a fit state to drive away and I can get some compensation for my damage... provided they are insured of course.
Provided no-one gets injured and the damage is paid for, I will sleep soundly in my bed.
Take care out there, this kind of accident is commonplace.