Standardise `embedded=yes` for Melbourne tramlines and elsewhere?

In Melbourne we have not only an enormous tram network, but a lot of it is complicated in its running mode. The same tram route can switch between street running on the road, street running on a segregated lane, and light rail mode off the road. Some of this diversity is captured in this blog post.

Currently the only standard tag we have to capture this is embedded_rails, but this applies to the road and not to the tramway itself. For this reason, there’s no way to query something like “what proportion of this tramline is street-running”.

Therefore, I’m wondering if we can come up with a more accurate tagging mechanism for Melbourne trams. One option is following the North American standard of embedded=yes on the tramline when it’s street running. This is good enough if we binarise the running modes and treat the exclusive/protected tram lanes as embedded=no. A more sophisticated tagging mechanism might capture more running modes, at the cost of being less compatible with North American tagging.

If this makes sense, how can I propose this for the Oceania (?) tagging guidelines? What about just making it a global standard?

embedded= only refers to the rails physically. It’s best reserved for that. It shouldn’t be mixed up with other aspects to show shared vs dedicated, whether the tramway is mixed with general traffic, bus lane, exclusive lane, or a dedicated physically separate part (which may be usable by maintenance, and emergency vehicles).
cycleway:*= has separation:*= and traffic_mode:*= (not to be confused with railway:traffic_mode= on =rail ). It could be used =tram and =light_rail . Proposal:Separation - OpenStreetMap Wiki
For the tram lane itself, it can’t directly follow cycleway:lane= =exclusive , =advisory ; or cycleway= =lane , =shared_lane , =share_busway . Something needs to be drawn up.
Also, currently can’t show the general characteristics of whether a section is center-running, one-side dual-track, or pair of track on both sides. That’s not easy to process.

Fair point. It’s true that using a combination of several tags borrowed from cycleway, you can capture all of this complexity. separation and traffic_mode can perhaps be used verbatim, but cycleway itself, which captures some important information too, obviously can’t be used. A tramway tag could have shared (with cars), lane (on the road but exclusive for trams) and light_rail (off the road) options, though only lane needs separation and traffic_mode.