That all looks fine, your Tertiary definition should be what is on the Wiki https://wiki.openstreetmap.org/wiki/Tag:highway=tertiary
Bumping Forest Resource roads up to Tertiary should be limited as they seldom can be interpreted as meeting the definition.
GnasherNF, I think your latest post and the example map looks pretty good. I’m not Canadian, but I grew up in the Northwest of the USA in an area with lots of forestry roads, and so I’ve become familiar with the different uses of track/unclassified/etc.
I’d probably keep most of those “tertiary” roads as “unclassified”, unless they have significant traffic due to settlements or other destinations, or if they have a number of highway=unclassified branching off of them. You mentioned a 60km long road; that might be a good example. I would think that a Tertiary road in Canada should be maintained annually by the local governement, or the local private forestry company or private land owners should officially maintain it. Perhaps this could be discussed with other Canadian mappers to find out if there is a more official way to determine when a road can qualify as Tertiary?
I would not think that winter snow clearance is a necessary characteristic of “maintenance”. In Portland, Oregon, even secondary highway will be unplowed during the rare snowstorms, and tertiary highways in Oregon and Washington are often impassable due to snow during the winter. Fortunately there are tags for seasonal closures, so an unclassified or tertiary road may be the correct tagging, even if it is only open during the summer, if the road sees significant public traffic during that season.
As far as highway=unclassified vs highway=track, I think it should be remembered that the highway classification system on OSM is primarily about road usage, not the quality of the road surface. So a badly-maintained road that is the only access for a set of residences or businesses should be highway=service if it is privately owned, even if it is surface=dirt, smoothness=very_bad and tracktype=grade3, and 3 meters wide. Clearly the residents and guests will need to use 4WD vehicles or ATVs of some kind for access.
But a gravel road with a relatively smooth surface and good drainage may be a track, if it is only used for logging/forestry vehicles or agricultural vehicles, and does not access residences, businesses or tourism destinations and is not maintained for the public.
I do think that in a developed country like Canada, a highway=unclassified should be passable by most passenger motor vehicles, however. Perhaps not sports cars or subcompacts with very low clearance, but regular cars should be able to get though, even if only at 10 km/h. And I would expect signs of maintenance: the road should not be 2 tracks or rutted out or have lots of vegetation growing between the wheel tracks, but should be regraded and maintained occasionally, since it is meant for public access. While minor roads in developing countries can be expected to be passable for 4WD/high clearance vehicles only, I would not expect this in North America.
I agree with your comments, except this part (quoted), but it boils down to how strictly we interpret the wiki. I’ve seen some major forest roads, wide and in exceptional condition built for heavy traffic, that would qualify as “track” by the criteria above, because they’re maintained for industry, not the public. (Public are tolerated as indirect landowners; common signage about “private road” refers to industrial users who are expected to contribute to upkeep.)
In my mind, if you can see two parallel tire tracks/ruts/grooves, it’s a “track”. If it’s smooth, even roughly smooth (but it sees a grader occasionally) - that wouldn’t be a track. But the wiki doesn’t make this distinction. Maybe it should?