[Tagging] Dispute prevention: meaning of lanes tag

Martin Koppenhoefer dieterdreist at gmail.com
Fri Apr 27 11:28:56 BST 2012


Am 27. April 2012 12:18 schrieb Kytömaa Lauri <lauri.kytomaa at aalto.fi>:
>>IMHO it would be a good idea to remove fractional lanes amounts and
>>forget about them. They are too subjective.
>>What do you think of lanes=3.5? I have an example here:
>>http://maps.google.it/maps?hl=en&ll=41.899274,12.464333&spn=0.008497,0.021136&t=h&z=16&layer=c&cbll=41.899391,12.464289&panoid=O8BHrnM_gTAW2XQUWqxcXg&cbp=12,353.6,,0,4.57
>
> When the lanes are marked on the ground, it ought to be an
> offence to drive continuously on the lines separating lanes;
> hence, there are only three lanes in the link above, even if
> some or many drivers think they can get away with it.


It's not that they think they get away with it: they _do_ get away
with it. If everybody in this area drives in a certain style, and
police doesn't enforce the official rules, then there are factually
more lanes on the ground than painted on the road.


>>Not sure, how many lanes these are, could be 5 or even 5.5? Depends on
>>the car widths and the experience of the drivers:
>>http://maps.google.it/maps?hl=en&ll=41.876836,12.481943&spn=0.000378,0.00066&t=h&z=21
>
> Changing lanes and overtaking within an intersection ought to
> be an offence in developed countries, so from the modelling point
> of view there can only be as many lanes as there are on any of
> the incoming or outgoing carriageways.


not sure, this is a point where _several_ (4) carriageways meet, each
of them with at least 2 lanes, and they don't go all in one direction
but in two, where for one of these it is also unclear how many lanes
there are (the other are 2.4 I'd say ;-) ).


>>vehicles can pass at the same time, lanes=1.5 doesn't really help you,
>>it will always remain unclear which width is the street.
> There are those roads (yes, roughly 4 meters wide) that, based
> on the overall setting, can not be called two lane roads, but it
> would be misleading to tag them with lanes=1, either.


yes, and even lanes=1.4 or 1.6 will be unclear. In these cases (which
usually also don't have painted lanes) the best thing to do is omit
the lanes tag and go for width. See also above in this thread.


> Aren't we supposed to safely assume that every road can be
> tagged with some correct lanes tag?


IMHO no, but if you insist on setting them, what about lanes=1,
oneway=no, width=4?

cheers,
Martin



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