I just had one “dead-end” road to complete in my village which seems forever behind a locked gate although Google Street View does show it open in 2 views about 10 years ago! I had hoped to “nip in” but then thought, even if I nip behind a car coming out, what if I can’t get back out again so have just done my first edit in OSM and have hopefully marked it as a private road. Assuming this works there are few other similar ones I think I will need to also mark.
More tricky however is that the A3 3 lane trunk road passes quite close to me. It is not a motorway per se but essentially it is as it has a hard shoulder alongside 70 mph traffic but, in a lot of places, there is no pavement/sidewalk/cycle path. In other words you would be risking life and limb to tick off those nodes. I am not sure however what the general policy is with such roads in excluding them? Don’t really want to exclude the whole road from Surrey to the south coast as many parts have safely runable bits to the side as mentioned.