[Tagging] `_link` roads in future `highway=*` proposals, and accounting for busway edge cases

[Colin Gzesh]

I am currently working on the proposal for `highway=busway`, and I'm trying it decide if it would be necessary to create an additional `highway=busway_link` to describe slip roads/ramps connecting the busway to other types of roads.

An argument for is that it could better account for edge cases, and it would make `highway=busway` more consistent with other high-level `highway=*` tags. An  argument is that `highway=busway_link` is unnecessary because any and all busway link roads would just be a part of the busway.

Please comment on this discussion thread:

https://wiki.openstreetmap.org/wiki/Talk:Proposed_features/Tag:highway%3Dbusway#Busway_links

This also relates to the topic of trying to come up with a definition of busway that most would be happy with. So far, I've really only received negative feedback about what types of roadways _should not_ be considered `highway=busway`:

> I wouldn't consider the lanes of a bus station <https://www.openstreetmap.org/way/347369893>, a bus-only highway ramp <https://www.openstreetmap.org/way/26944642>, a bus-only way through an intersection <https://www.openstreetmap.org/way/210447794#map=19/51.51006/-0.13424>, or a bus garage driveway <https://www.openstreetmap.org/way/825730684> to be a busway. Marcel.dejean <https://wiki.openstreetmap.org/w/index.php?title=User:Marcel.dejean&action=edit&redlink=1> (talk <https://wiki.openstreetmap.org/w/index.php?title=User_talk:Marcel.dejean&action=edit&redlink=1>) 17:19, 20 March 2021 (UTC)

It would be really useful to me for members of this mailing to propose a definition that the community at large would be happy with.
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Sincerely,
Colin Gzesh