Hello! https://www.openstreetmap.org/node/10274982957/history has access:bus = private that was added in this edit
Would using bus access tag (see https://wiki.openstreetmap.org/wiki/Key:bus ) be fitting at least equally well?

Usage statistics are sometimes wrong and should not be blindly followed, but are worth looking at - see http://taghistory.raifer.tech/#***/bus/&***/access%3Abus/