Validator - add a test for traffic_signals=* - less specific or undocumented values

[rskedgell]

Would it be possible to add a test for some values of traffic_signals=*, e.g.

traffic_signals=signal
From the wiki: "Since this kind of signal is assumed for highway=traffic_signals, please choose a more specific value for a more specialized signal."

traffic_signals=crossing
Not documented in the wiki, but more specific values are: level_crossing, pedestrian_crossing, cyclist_crossing

​https://wiki.openstreetmap.org/wiki/Key:traffic_signals

[taylor.smock]

Would it be possible to add a test for some values of traffic_signals=*, e.g.

Yes. Should we? I don't know.

traffic_signals=signal is acceptable, just generic and assumed. It also has extremely wide usage (probably because of iD). I don't think we want to have different editors treating the same tag differently (iD considers it valid tagging and adds it by default, JOSM considering it as too generic and showing a warning).

traffic_signals=crossing is not documented, but I can see why it would be used over the other *_crossing tags, since many mappers are using aerial imagery only. I'd rather have StreetComplete add a survey question for it. How would a light for pedestrian and cyclist crossing be handled? traffic_signals=pedestrian_crossing;cyclist_crossing?