This is my first time encountering this tag but from what I get from the wiki page this is arguably one of the most subjective tags I’ve seen. It seems to pretty much disregard regional differences, cyclist’s experience and the median level of comfort in a given settlement. I live is a small city with nonexistent bike infrastructure - what is provided as an example of class:bicycle=-1 looks better than anything you’d find here. While this may sound bad at first I’d still be comfortable and safe enough to get distracted from the road for a bit and allow myself to fiddle with the phone attached to the handlebar (e.g. to check the map, skip a song in Spotify etc.). What I’d describe as “avoid at all costs” is the highway outside of the city with cargo truck traffic and the speed limit of 90 km/h (+20 km/h oopsie allowance). So, should we just give up any attempts to make those numbers mean anything universal and just assign “class:bicycle=-3” to a “literal fury road” and “class:bicycle=+3” to “as good as it gets”? If so, where exactly should the border be drawn with a la la land where “class:bicycle=-3” means “I’m slightly inconvenienced” and “class:bicycle=+3” stands for “all cyclists go to heaven”?

I mostly judge by how roads/tracks work in Ukraine so that’s how I see it:

Tracks:

• typically completely unpaved (only the segments directly adjacent to proper roads may be paved and tagged as tracktype=grade1)
• are not bound by man-made features at least on one side and are therefore prone to drift over time
• appear informally and typically unmaintained or maintained by individuals rather than organizations
• may appear on settlements’ outskirts or even inside within large unbuilt areas (greenfields); these must be retagged as proper roads once paved or buildings appear on both sides
• are essentially desire paths for vehicles

Service roads:

• typically paved (including gravel)
• do not drift over time
• almost never have lane markings, sometimes might have traffic signs but mostly they don’t
• can be found within or leading to dense residential, commercial, industrial properties
• can be a narrow part of a named street where two buildings/fences are so close to each other that only one car can physically fit in
• named/numbered lanes within allotment areas
• theoretically maintained

Unclassified:

• long (at least several hundreds of metres)
• wide (5+ metres) graded or paved road connecting a settlement to some commercial, industrial or agricultural propertior another minor settlement
• usually doesn’t have a name or an index
• paved, often marked roads with restricted access within industrial complexes that are significantly wider and longer than service roads and with fewer turns
• theoretically maintained
• if indexed should be tagged as tertiary
• if degraded to the condition of a track (e.g. the endpoint of a road is abandoned) but is indexed, a “virtual” highway existing only on paper