[Tagging] Tags useful _SUMMARY_ for rendering of roads in poor conditions

[Kytömaa Lauri]

>Tracktype= has about 2.5 million grade2 and beyond ways. "Tracktype is a
>measure of how well-maintained a track or other minor road is."
>http://wiki.openstreetmap.org/wiki/Tracktype

Having now read through the messages, I find that nobody has mentioned a thing about tracktype, as it was initially described and used; and how the values are still described.

Even if there's usually a correlation (even a strong one), it's not directly about how easily some vehicles can get through, but about the mixture of hard materials and soft materials.
grade1: just hard materials
3: roughly 50/50 mix
5: only soft materials

What's beyond "only soft materials", foam? And true, in this some surface= values are impossible with some of the grades.

Many extreme_4wd_only rocky ways could be even grade2; it's the clearance needed and the inclines that set their limits, not the mixture of soil present. Likewise, that golf club grass footpath may well be grade5.

But maybe the usage has overruled the strictly physical characteristics that it used to describe and the values are used for all sorts of different ideas? If so, then this is again a case where the community failed in documentation back in 2008, or sometime after that when the pages were subsequently "improved".

-- 
Alv