[Tagging] How to tag an imaginary oneway barrier

[Kytömaa Lauri]

Martin Vonwald wrote:
>>3 Cut the way where the sign is into a tiny piece of way.  Add a motorcar:backward =no  to this tiny piece of way.
>
>That variant has been used in my area. The "tiny piece" is usually the part from the junction up to where the sign is located.

This is the oldest common simple way to mark these. Vehicles have length and can't turn around without moving forward at least somewhat (save for some machinery), so there's always a short section of the road, where the affected vehicles can't be moving in the "forbidden" direction. If they were moving in the forbidden direction, they would have had to pass the prohibition sign; straight up or during the u-turn. That short section is effectively oneway (for all, or some vehicles).

I didn't take note who argued that the short section represents something "virtual", so I say my point here:
The "tiny piece" as described above is no more "virtual" than the other ways that meet at the junction. The fact that the osm ways, if they were extruded into areas, form overlapping areas, is just a consequence of the data model.

-- 
Alv