IMHO the handling of private roads in OSM is poor and very confusing.
In the UK there are plenty of roads (usually cul de sacs) that say “Private Road” but there are no physical restrictions. I think that basically means maintenance of the road is not in public hands. I believe this is where the “ownership=private” tag is probably more relevant than access=private. If I “draw” a new private road like this I now tend to set ownership=private but leave access as the default access=all.
Then they are similar “Private Roads” that have clear resident only parking signs where you can freely enter on foot but best not park there and nip to the shops etc etc for fear of a fine and/or clamping ! I would view them as motor_vehicles=private Less clear otherwise.
Then there are roads with a gate that is usually locked and whether you can open the gate or not “on demand” I might “try” to run them but the access is clearly private for all and I would mark them as private on OSM especially if I could not get in!
Then there are roads with security guards at the entrance that the other day I managed to slip past, tick off a few roads that were not marked as private on OSM but on getting near the exit, a guard took great delight calling me back and telling me you can’t run in here and not to do so again! Fortunately I had ticked them all off anyway! I marked them all as private on OSM to stop any other Striders being told to b***er off in the future!
Then there are private estates with barriers for cars but pedestrians are not physically restricted and often such places are full of pedestrians and who knows if they live there or not and so have some implicit “permission”. Some of them (including one I did last night) actually have some rights of way within them and this one even along one of the main roads but technically if you take a turn of it you should not. Some of these “private” roads off this “public” road are marked access=all on OSM as nobody has taken the trouble to change the default. As I found they were freely accessible I ticked them off (and very pleasant too) but do I now go and “correct” OSM as really it needs consistency. You can’t have a “public” road only accessible via a private one. But then I would “lose” some streets 
Personally then there ought to be clearer levels of “private” - technically in private ownership but no real issue accessing and “fully” private where the public are “prevented” from accessing full stop.
The guidance on OSM I find can be contradictory.
Key:access - OpenStreetMap Wiki says “Public access is not allowed. Access is granted with individual permission only.”
That is somewhat more “strict” than Tag:access=private - OpenStreetMap Wiki which says
Note that access=private
is intended to indicate that access is restricted , not whether the object is privately owned or not. Use ownership=private
or operator:type=private
to record this kind of status.
So practically, I only mark up a road on OSM as private if indeed I was “restricted” in entering it either by a gate or an irate security guard.
If I see a road marked as access=private that I view more as ownership=private I tend to leave it as is unless it is clearly a “thoroughfare” at least on foot - say if a public footpath emerges onto it.
access=destination I don’t really “like” as view it as a bit non standard and you could argue all cul-de-sacs whether clearly public or not are for the purpose of accessing/visiting a house on there as who really runs up a dead end for the fun of it other than us 