In 2002 I was travelling Europe by car with my girlfriend at the time and in late afternoon on a winters day we arrived in the snow covered town of Andorra-la-Vella, the capital of the tiny principality of Andorra which is in the mountains between France and Spain.
Our intended destination for the evening was a camp site about 20 kilometres out of town and as we left town the sun started to go down and it started snowing again.
About 5km out of town I decided conditions had worsened to a state where I was not comfortable continuing. We could no longer see the road and were relying on the road marker poles on each side of the road to tell if we were still on the road or not
We managed to get the car turned around and very slowly drove back to Andorra-la-Vella. For the trip back to town the sun was well gone and we were staring out the windscreen looking for the reflector on the next road pole at walking pace.
As we arrived back in Andorra-la-Vella I saw flashing lights behind us as a service vehicle pulled up and closed gates across the road, shutting it off to all traffic.
All the while this was going on all I had on my mind was that we were in a white car, in a snow storm, at night. If something had gone wrong we wouldn't have been found until the snow melted in Spring.
I think roadside snow poles are a european thing. Anywhere that regularly gets snow has them so even if the snow is fairly deep you can see where the road goes.