[Tagging] Dispute prevention: meaning of lanes tag

Ilpo Järvinen ilpo.jarvinen at helsinki.fi
Sat Apr 21 12:34:56 BST 2012

On Sat, 21 Apr 2012, Ronnie Soak wrote:

>       In my opinion, lanes=1.5 is a very bad choice. We have a tag for
>       this situation: width . According to taginfo, lanes=1.5 is used,
>       but not too often. What should we do? I would recommend not to
>       use it and advise to specify a width (which is also objective
>       rather than subjective as 1.5 is).
> +1
> The width-tag is widely used, is more general and part of the standard set
> of fields for many highway-categories in JOSM and Potlatch.
> It may be harder to estimate a width in meters instead of a lanes count, but
> I think it's possible within +/- 1m, especially for narrow ways.

This difficulty is very true and it disallows collecting more than few of 
them at a time since you'd have to remember/note those estimates until you 
have a computer with which you can put that into the db.

> (I personally only use it with either rather narrow or rather wide ways out
> of the norm.)
> The lanes tag is used with integral numbers, most tools won't recognize
> fractions. And even if they do, it's still highly subjective if it's lanes=1
> or lanes=1.5 or lanes=2 if there are no road markings. (If you have to slow
> down to pass depends on your type of car, the road (and weather/sight)
> conditions and your bravery/insanity.) 

I'm not really convinced by the subjectivity fear in this case. It's 
always quite clear when the road is clearly wider than a single lane (and 
that is provable too in many cases as you are able to spot few cars 
passing by ;-)). And on the other end, it is not extremely hard to
estimate that it would be rather challenging to pass an incoming car 
without slowing down.

...What I don't really care if it is called lanes=1.5 or 
lanes=1/2+some_other_agreed_tag_which_is_not_an_estimated_width=x, but 
simply saying that use lanes=1/2 alone instead I oppose.


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