Honestly I can’t give you a proper answer here. I never actually thought about it before so I just looked up the Slovenian law about it (I don’t speak German so I didn’t bother with the Austrian one) and I couldn’t find anything that specifically says that the snow poles must/can’t be there between XY dates (just a bunch of stuff about how they gotta be positioned). If I had to guess it is a mix of these things:
Aesthetics
Visibility
Giving the road workers something to do
It is how it has always been done. Before these combo bollards became a thing and in places they still haven’t replaced the old ones they still add/remove a full on wooden snow pole next to the bollards every year.
There might be some other reasoning for it too, but this is what comes to mind as possible options.
What’s the reason to not just have the pole permanently attached on top, instead of retracting?
Honestly I can’t give you a proper answer here. I never actually thought about it before so I just looked up the Slovenian law about it (I don’t speak German so I didn’t bother with the Austrian one) and I couldn’t find anything that specifically says that the snow poles must/can’t be there between XY dates (just a bunch of stuff about how they gotta be positioned). If I had to guess it is a mix of these things:
There might be some other reasoning for it too, but this is what comes to mind as possible options.