[Tagging] Feature Proposal - RFC - Turn Lanes

[Ilya Zverev]

Martin Koppenhoefer wrote:

> I wonder if in this case:
> http://wiki.openstreetmap.org/w/images/6/69/Simpleuklanes.jpg

> it would not be better to draw 2 ways (and add a relation to say that
> you could - against the traffic rules or maybe as a pedestrian - 
> cross
> the street from one way to another?

Yes, my opinion is that all highways that are more that 4 lanes wide 
should be drawn as two ways. Alas, it seems that most mappers recommend 
drawing one way if there is no physical divider, even if there are 4 
lanes in each direction.

> Otherwise there should be a way to indicate that you cannot use the
> opposite lanes (say for takeovers) because of the area in the middle
> of them (diagonal white markings).

There was a proposal for tagging type of divider, but it has been 
abandoned for several years:
http://wiki.openstreetmap.org/wiki/Proposed_features/Divider

> How would you tag a lane according to this proposal that allows at 
> the
> same time e.g. to go straight and left?

Lanes separately are not tagged, only lane groups. In this case there 
are one lane group for turning left and one — for going straight. So it 
would be lanes=N, lanes:turnleft=1, lanes:through=N. If the left lane 
was used _only_ for turning left, lanes:through tag could be omitted.


IZ