text: Hi, 'width' seems to mean the width of an object, not of the gap inside it. Only on roads (highway) that may be the same as the possible widths of vehicles that can drive it. For that maxwidth:physical seems to be the right tag, as you said.
  I have made a pull request into OsmAnd to support maxwidth:physical in car navigation mode.
  
  I have also retagged similar barrier in Slovakia at https://www.openstreetmap.org/node/9508004170 from motor_vehicle=no to maxwidth:physical. There is also a photo of the barrier at https://www.openstreetmap.org/note/2611935 .
  
  Please tag the barrier on this Austrian road as you proposed so that we can resolve this note. Thanks