# [Tagging] Lane dividers

Tobias Knerr osm at tobias-knerr.de
Wed Oct 17 11:00:48 GMT 2012

```On 17.10.2012 09:31, Martin Vonwald wrote:
> Obviously we need some kind of tagging for lane dividers. Initially
> when writing the :lanes proposal I though about reusing the divider
> proposal: http://wiki.openstreetmap.org/wiki/Proposed_features/Divider
>
> But this has one serious drawback: if you have a road with four lanes
> you would tag e.g. turn:lanes=left|through|through|right . That's four
> lane-values. But if you want to tag the dividers you would need
> divider:lanes=solid_line|dots|solid_lane . That's three lane-values.
> In my opinion that's not a good idea - I would like to have the same
> number of lane-values for all keys.

This problem does indeed exist, but it only appears with oneway roads
because no obvious definition exists what the plain "divider" key means
in that case.

With two-way roads, directly applying the divider proposal could work
quite well: You have divider=* for the central divider between the
directions - that option should be kept anyway because often the other
dividers are much less interesting. Then divider:lanes:forward/backward
refer to the "outer" divider for each lane.

> Now (a time ago) I came up with something different: have a look at
> part 3 of the first example:
> http://wiki.openstreetmap.org/wiki/User:Imagic/LaneMapping *
>
> Please keep in mind that's just a first idea! What do you think?

That is a very different approach from the divider tag. It amounts to
tagging one of the effects of the divider, rather than the divider
itself, so there is a lot of information missing. I don't really see how
the above argument about the number of values leads to that completely
different solution.

Tobias

```