[Tagging] Dispute prevention: meaning of lanes tag

Georg Feddern osm at bavarianmallet.de
Fri Apr 27 12:25:32 BST 2012

Am 27.04.2012 11:54, schrieb Ilpo Järvinen:
> ...But how can I tag you this: A road which is lanes=1+wide _AND_
> lanes=2+narrow at the same time? ...You ask me to provide width and select
> one of those two, and that is what I oppose, unless you give me some real
> tag that is not width to tell that 'hey, there really isn't lanes marked
> (which makes it kind of lanes=1) but two can somewhat fit (which makes
> it kind of lanes=2 but not really because it's only "somewhat")'!

I think I understand what you mean, because I see that in many rural 
cases here

Perhaps just to clarify at least my observations / understanding
which will hopefully match your differentiation:

A) lanes=1
Means no chance to pass but on special passing points.

B) lanes=2
You can always pass without leaving the tarmac and without special 
precautings (like driving very slow on the outer side)
Well, the latter may depend on experience and spatial sense! ;-)
And I talk about lorries / busses, not a special 
"passenger-cars-only-2-lane-road" (see C).
But I am afraid this is already ambiguous in the data too ...

C) lanes=1.5
To pass you may have to leave the tarmac depending on the oncomming 
vehicle, but there is always enough place to do so.

I have to admit, that I would tag C) as lanes=1, because even there is 
always enough space
- you have to leave the tarmac and so you have to leave 'your  lane'
- you never know what's beside the tarmac, which will lead to special 

For me C) has simply the same driving limitations as A):
Always expect oncomming traffic you cannot pass without precautions.

Together with width it is possible to refine your capabilities depending 
on your own vehicle and driving characteristics then.
Then you may know, if your small vehicle can pass every oncomming lorry.
But lanes=1.5 has no benefit or information here - not even for a 
cyclist, if you mean a 1.5 passenger car width - and the lorry is coming 


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