Well said, I agree wholeheartedly. A local, anecdotal view is in itself
not enough to produce a data model that works for everyone.
On 2018-09-22 14:22, Tobias Zwick wrote:
> Tagging an implicit speed limit explicitly for example in town with
> maxspeed=50 is straightforward enough for Germany. It seems natural that
> no specialist knowledge is required for that kind of thing. For a German.
>
> But let's look at some other countries for the default urban speed limit.
>
> Spain (ES):
> maxspeed=50
> maxspeed:hazmat=40
>
> Chile (CL):
> maxspeed=60
> maxspeed:bus=50
> maxspeed:hgv=50
>
> Hungary (HR):
> maxspeed=50
> maxspeed:tricycle=40
>
> Kerala in India (IN-KL):
> maxspeed=50
> maxspeed:conditional=40 @ (weight > 7.5)
> maxspeed:trailer=40
> maxspeed:bus_articulated=40
> maxspeed:hgv_articulated=40
> maxspeed:bus:conditional=40 @ (weight > 7.5)
> maxspeed:hgv:conditional=40 @ (weight > 7.5)
> maxspeed:tricycle=30
>
> Punjab in India (IN-PB):
> maxspeed=50
> maxspeed:trailer=35
> maxspeed:bus_articulated=30
> maxspeed:hgv_articulated=30
> maxspeed:hgv=45
> maxspeed:hgv:conditional=40 @ (weight > 6)
> maxspeed:conditional=40 @ (weight > 6)
> maxspeed:trailer:conditional=30 @ (weight > 6)
> maxspeed:motorcycle=35
> maxspeed:goods=45
> maxspeed:goods:conditional=40 @ (weight > 6)
>
> Malta (MT):
> maxspeed=50
> maxspeed:bus=40
> maxspeed:hgv=30
> maxspeed:goods=40
> maxspeed:goods:conditional=30 @ (weight > 3)
>
> Poland (PL):
> maxspeed=50
> maxspeed:conditional=60 @ (23:00-05:00)
>
> Zambia (ZM):
> maxspeed=50
> maxspeed:conditional=40 @ (weight > 2.275)
> maxspeed:trailer=40
> maxspeed:hgv=40
>
> Because the maxspeed tag applies to all vehicles except overridden for a
> specific vehicle type or a conditional, specifying only maxspeed=50 in
> any of the above cases has to be considered wrong or at least
> incomplete. In other words, the tags you see above would need to be
> added in the case the speed limit is given explicitly. It is not so
> straightforward then anymore.
>
> So, maybe not for Germany, but as you see, in other places, this *is*
> specialist knowledge. No regular car driver in Punjab will be able to
> enumerate all these maxspeed rules. And, taking a less extreme example,
> I think the Polish OSM contributors wouldn't want to add this
> maxspeed:conditional=60 @ (23:00-05:00) to every single unsigned street
> in urban areas.
>
> Also, note this is only the urban speed limit, trust me, the default
> speed limit "for all other roads" (=rural) can be much more complex.
>
> Actually, don't trust me, see for yourself in the document I link all
> the time in the hope people would read it:
> https://wiki.openstreetmap.org/wiki/Default_speed_limits
>
> We can not get to any results or any progress on the matter of default
> speed limits (or for any topic, for that matter) if everyone just keeps
> arguing out of his best knowledge about his home region or country only.
>
> "It works for me" is simply not good enough for a global project.
>
> Cheers
> Tobias
>
> On 22/09/2018 01:03, Martin Koppenhoefer wrote:
>
> sent from a phone
>
> On 19. Sep 2018, at 21:16, Tobias Zwick <o...@westnordost.de> wrote:
>
> This is a good argument against tagging an explicit maxspeed=X when
> there is actually no speed limit sign around (X is what the OSM mapper
> by his knowledge about the law thinks should be the default limit here).
>
> everything that you map will be according to your understanding of it, I
> cannot see a good argument for not tagging implicit limits, even more as
> there is judgement needed based on the situation (something humans can do
> much better than computers). Every holder of a driving license should have
> the requisites to recognize the speed limit on a given piece of road in their
> local area, so it doesn't require specialist knowledge.
>
> We already have a reliable way to distinguish implicit from explicit limits
> (we even have several of them), if you want to treat them differently in your
> app, you can do it.
>
> There actually is a speed limit on most roads, including those without
> explicit signage. Omitting it will leave us in the situation that it really
> becomes unclear whether there is no sign or nobody has bothered to enter it.
>
> Cheers,
> Martin
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