[Tagging] lanes:psv, lanes:bus - reserved or available?

[Bert -Araali- Van Opstal]

Thank you Paul, for sure, what we have in most cases, if you are 
creative allows us to tag simple, but also detailed and sometimes 
complex situations.
I think however there is a need to bring more clarity in the whole 
concept to serve several purposes:
1. Avoid tagging schemes that promote data to be repeated. Over time 
data consistency gets jeopardised, it creates confusion amongst common 
users but also at specialised use cases, like I can't find any routing 
application that uses OSM's lane tagging schemes for reserved lanes, 
yet, is that caused by data inconsistencies, overlapping tagging 
schemes, or just a functional option not yet provided by the routing 
application, I don't know but duplicating data surely contributes to 
that issue.  It's like normalising a database scheme to avoid all kinds 
of confusion and a "mess", our data scheme is not normalised.

2. Avoid using values that don't add any clarification to the concept.  
I refer to your advise to use access:lanes=no|yes|yes. Yes or no doesn't 
add anything here to the already psv:lanes tagging. The "no" value means 
what, no psv's, no bicycles, no motorcycles ? It needs to be related to 
a specific access value, like psv, hov etc.... So one could see value in 
access:lanes=psv|yes|yes, yet, then my question would be again what does 
this add to the already psv:lanes which defines clearly the access, the 
location and the number.

So in my opinion their is an opportunity and a need to take some actions 
here, not to normalise completely (that is too big to do in one step, 
needs a master plan) or promote one classification principle in favour 
of another but at least to deprecate tagging that contains duplicate 
data or non-deterministic values.
In this particular case:

A. clarify lanes=* does count all the lanes (including dedicated) of the 
way where the tag is used (supports both highways where lanes are mapped 
on a single way as where lanes are mapped as single drivelanes with each 
there own way);

B. consider promoting specific access lane tagging schemes like 
psv:lanes or access:lanes but deprecate all the separate lane counting tags.

C. Discourage the use of general values as yes/no in the access lane 
tagging schemes that don't refer to a specific access category.

Maybe a small clarification to normalisation: normalisation should not 
mean we favour a certain classification principle. Different 
classification systems deserve and should be supported by OSM. 
Normalisation should be practised on different classification principles 
but avoid duplicating data in the same sense.  That way we get competing 
tagging schemes, that might contain duplicate data in competition with a 
different classification principle, however most of the time they can be 
considered as different as they might be overlapping but not exactly the 
same across different classification principles. This justifies the 
existence also in other examples which are bothering us for a long time 
like the competing landcover and natural tagging schemes. Normalisation 
should however eliminate completely identical and duplicate values.

Greetings,

Bert Araali

On 24/02/2021 09:36, Paul Johnson wrote:
> On Sun, Feb 21, 2021 at 3:26 PM Bert -Araali- Van Opstal 
> <bert.araali.afritastic at gmail.com 
> <mailto:bert.araali.afritastic at gmail.com>> wrote:
>
>     Struggling for long time with the same issue Mateusz. It is not
>     clear if the PSV lane count should be counted in the total lane
>     count or not, if they are deicated.
>
> I would say "yes, they do count", lanes=* should be all lanes, 
> including reserved lanes.  I would also argue regardless of the width 
> of those lanes, as well.
>
>     What seems to work though is to use psv:lanes instead and define
>     the psv usage of each lane individually, without providing
>     lanes:psv as a separate count (dedicated or not).
>
>     So in your example we would get:
>
>     lanes=3
>     psv:lanes=dedicated|yes|yes (notice we drive on the left hand
>     side, so we tag the lanes in the driving direction from left to
>     right and reserved psv lanes are mostly located on the "outer" lane)
>
> I would say this is correct.  This also works for bus lanes, hov lanes 
> and bicycle lanes.  If the lanes are exclusive to that use, be sure to 
> also add access:lanes=* as well to set the default access for the lanes.
>
> So, for your example above, if only PSVs are allowed in the left lane, 
> then also add access:lanes=no|yes|yes.
>
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