LoMaps legend explaination

1) I would like to understand the link between some categories of OpenStreetMap and map legend of LoMap Hike & bike theme.

For "Utilitary roads", this is my understanding.

• Tarmac/concrete. ?
• Gravel. [highway = track, tracktype = grade 2] ?
• Mostly compacted. [highway = track, without tracktype] and [highway = track, tracktype = grade 4] ?
• Uncompacted ?
• Path. [highway = path] ?

2) It is difficult to make graphicaly difference on the map between :

Highway - Unclassified / Residential / Service and

and

Utilitary roads - Tarmac/concrete