You’re talking about a metalled (asphalt, bricks, etc) road so narrow that cars cannot pass each other except on special passing places? If that’s the case I think it should be either:

  • highway=track, tracktype=grade1 with some nodes having the attribute passing_places=yes. This contradicts the definition of track though (track being declared as mostly a private road).
  • highway=unclassified, width=x (approx. width in meters) with some nodes having the attribute passing_places=yes. For a public road this might be the best option.

Please note that there are no ‘official’ tagging standards for such situations yet but it’s being discussed in various places e.g. in the wiki (just search on: layby, passing place or tracktype etc).