How should a road crossing combined with tram lines be mapped?

At Changeset: 129937132 | OpenStreetMap , we are disagreeing about how to map road lanes when they mix with with tram lanes at a complex road crossing.

There are two opposing views (please correct me if I summarize incorrectly):

  • Map the road as two ways. Downsides: not following guidance at Key:lanes - OpenStreetMap Wiki + we map traffic islands that do not exist
  • Map the road as one way (with several lanes). Downsides: we map tram level crossings that do not exist + we map sharp turn that does not exist

There is some discussion between me and user tvbrene in the comments of the changest. Can we get input from other editors please? Thanks for your time!

Could you please share a picture of the situation?

Sure, here is one up-to-date view from Google Maps (this file will delete in 7 days)

The GeoBasis-DE/LVermGeo LSA, DOP20 background in the iD editor is also up-to-date

I’ve like to add, that I’m not opposed to using only one way on principal level. But like it’s done currently the way just isn’t able to match the situation. As you can see the left and right turn from Warschauer Straße to Schönebecker Straße are separated with a traffic calming on the Schönebecker Straße. The current way ends on the right side of the traffic calming in a 45° angle, the existing left turn lane on the ground ends at a 90° angle on the left side of the traffic calming. Also an empty space between to ways doesn’t automatically constitutes a traffic calming, then we wouldn’t need to draw and tag them.

The situation is special. The lane in south west direction in Warschauer Straße shares the lane with the tram. The lane in north east direction for the tram is exclusive, no other vehicle is allowed to used that lane and the lanes (turn lane left and turn lane right) for other vehicles are at the right side of that tram lane and after about 80 m the lanes are split again to map a traffic calming, so I’ve opted for two ways instead of one to better match the situation on the ground even though I normally would prefer a single way.

I didn’t took the situation lightly when I’ve created the ways for the street after the tram was added to the street. If one way is used then it should at least be mapped between both railways to prevent creating train crossings that doesn’t exist and use placement.

Central Portland, Oregon has multiple examples to choose from on how to handle this.

Well I’ve only found one spot in Portland Oregon that is kind of comparable.
The street view of that spot shows 2 lanes for tram in the middle and lanes for other vehicles on the side. It looks like it can be driven on the railway lanes with cars but it’s not allowed to do so. The surface differs the railway is paved with sett and the car lanes are asphalt. But clearly it’s just one street without any kind of barrier between the car lanes and the railways, still it uses two ways for the car lanes instead of a single one in the middle of the railways.

So it’s drawn like I had drawn the Warschauer Straße. I’m sure one would be able to find other spots that are drawn differently but clearly nobody went in and just replaced the existing data at this spot in Portland Oregon.

+1, for your approach with a single two-way road. Eventually, you could add embedded_rails:lanes=* or even railway:lanes=*.
To solve the intersection, I would use an additional way for the left turn lane starting from the pedestrian crossing on Warschauer Straße to Schönebecker Straße as there is a small traffic in the middle of Schönebecker Straße.

By the way, there is a problem with Way: ‪Warschauer Straße‬ (‪1120776547‬) | OpenStreetMap as turn:lanes:forward should be turn:lanes:backward.
As the Saxony-Anhalt imagery seems to be up-to-date I could try to enhance the junction with many :lanes tags if you appreciate help and a well tagged example.

When I’ve mapped that new layout of the Warschauer Straße I’ve opted for two separate ways for this 80 m segment because there is a separate way when turning right from Schönebecker Straße, a full sized railway lane that is exclusive for the tram between the car lanes and then there is a traffic calming. Like it is now the street makes additional turns that aren’t even there (of course that is unavoidable when switching from one way to 2 ways for the traffic calming). That’s what I meant when I wrote special situation. When zooming in, the map currently looks like the railway in south west direction is separated from the lanes for the cars but that railway is also the lane the traffic is routed on. It is represented way better with using two ways just for this 80 m segment.

In the segment after the traffic calming (and before the next) the street consists of 3 lanes that are all used by the traffic with no separation, so I’ve drawn that segment as a single way. That segment would be a good case for tagging embedded_rails:lanes because the middle lane used for turning has no rails.

We have other streets in Magdeburg with two ways for instance Way: ‪Leipziger Straße‬ (‪366146901‬) | OpenStreetMap
In that case there is a physical barrier in form of a lowered kerb, but it still can be driven on the railway, nothing really hinders driving on the railway other than that it is not allowed to do so. Or take Way: ‪Lübecker Straße‬ (‪745364181‬) | OpenStreetMap, there is no physical barrier for most parts of the street, it’s even allowed to drive on the railway partly and then the only separation is a double line in the middle for that parts, still 2 ways were used for that street, which is a lot longer than 80 m.

So my point is, there was simply no reason to make one way of the existing 2 ways for that 80 m segment and that it is not better now, but worse. The junction clearly had too many ways but that could have been fixed without going overboard.

I understand your point here. My view on this is that there is no physical barrier and at least emergency vehicles can use the lanes exclusively for trams and even cross the lanes to reach destinations of the left side or make a u-turn.
As already mentioned, I fully agree that there is a short way for left turns from Warschauer to Schönebecker Straße missing, atm.
Regarding the unavoidable additional turns placement=transition is a tag to give a clue that angles at the first and last do not represent reality.
The representation largely depends on the renderer and the tags it interprets but a proper representation is possible with current tags like width, width:lanes and placement as

embedded_rails:lanes can be used everywhere where not all lanes embed a rail which is useful for e.g. bicycles and motorcycles (example).

In case of a lowered kerb I am not sure what the best solution might be as the barrier is not exactly a physical barrier.

Here I would only use one way for the street similar to my example above.

In the end, it is up to the local community to decide how to map these in between cases. Both have advantages and disadvantages and the final solution is probably area:highway. I only tried to share my view.