Hello!
I’ve been mapping in Japan for a while, and I saw some strange road tagging, like this:
There’s no difference on Bing imagery between this highway=teritary and highway=residental roads.
http://www.openstreetmap.org/edit#map=18/42.80463/140.68347.
Generaly speaking I find the osm map of Japan is very dense.
After doing some research I came to a conclusion, that the Japan road tagging guidelines, avaible at https://wiki.openstreetmap.org/wiki/Japan_tagging#Road_types, stand out from tagging in other countries. My main concern here is that there’s very little difference between Teritary, Unclassified and Residental.
I want to propose a different system for road tagging in Japan, that would be cleaner:
highway=motorway - Expressways (高速道路) - https://en.wikipedia.org/wiki/Expressways_of_Japan - No change from current tagging
highway=trunk - Class 1 National Routes (一級国道) - https://en.wikipedia.org/wiki/National_highways_of_Japan - All highways with highway=trunk and 1 or 2 digit ref= value, except for ref=58.
highway=primary - Class 2 National Routes (二級国道) - (same article as above) - Currently all highway=trunk roads and ref= 3 digit long, or ref=58
highway=secondary - Major prefectural road (主要地方道) (1 or 2 digit long and hexagon shape) - https://en.wikipedia.org/wiki/Prefectural_road - Currently all highway=primary
highway=tertiary - Minior prefectural road (一般地方道) (3 digit long and hexagon shape) - (same article as above) - Currently all highway=secondary
highway=unclassified - Other roads connecting cities, towns or villages - Currently all highway=teritary
highway=residental - Roads within nieghbourhoods - Currently all highway=unclassified and highway=residental
The difference between highway=unclassified and highway=residental should be as stated on highway=residental OSM wiki page: https://wiki.openstreetmap.org/wiki/Tag:highway%3Dresidential.
I tried to make the tagging scheme easy to migrate from the current one - the only roads that need to be changed manually are some prefectural road links (current highway=trunk_link) without the ref= tag.
In the end I just want to ask you what do you think about the current tagging scheme, and what do you think about developing a new scheme.