nebulon42
I'm not sure how the situation is now. Back when there were border controls (now there are also border controls but not in this direction) this lane was used to divide trucks and busses (?) from the rest of the traffic. Now maybe only trucks, but maybe also not all the time, so the lane might be unused. When there is a lot of traffic trucks might be prohibited from driving trough Karawankentunnel / Karavanke due to safety reasons, so they might be rerouted here. I'm also not sure if hgv=no, bus=no on https://www.openstreetmap.org/way/199341050 is accurate. Maybe best to remove the access restrictions as they are likely temporary and change over time.