[Tagging] maxspeed:type vs source:maxspeed // StreetComplete

Paul Johnson baloo at ursamundi.org
Wed Sep 19 12:18:17 UTC 2018


On Wed, Sep 19, 2018 at 7:09 AM Greg Troxel <gdt at lexort.com> wrote:

> Tod Fitch <tod at fitchdesign.com> writes:
>
> >> On Sep 18, 2018, at 6:19 PM, Joseph Eisenberg <
> joseph.eisenberg at gmail.com> wrote:
> >>
> >> So on the boundary=administrative admin_level=6 for Rogers County, we
> could have something like maxspeed:type:default=45mph
> >
> > Except that more typically there will be different default speed
> > limits on each of the various OSM highway classifications. So maybe
> > something more like “maxspeed:default:residential=25 mph”.
>
> I am not aware of *unposted* default limits in the US being different by
> an entity smaller than state.   In Massachusetts, there are default
> limits in state statutes, in particularly 30 mph in "thickly settled"
> areas (also defined in statute).  Some towns have adopted 25 mph in
> thickly settled areas, and they have signs at the town borders.
>

Kansas and Oklahoma definitely do, often putting a specific default limit
in their town's motor vehicle code.  Tulsa does this, and it's in the top
1% largest of US cities.


> It's an interesting question at what level to tag individual roads and
> when to have some way of expressing rules and therefore to expect all
> data consumers to evaluate the rules.  My quick reaction is that
> publishing rules for regions smaller than states is going to be too
> messy, vs just tagging the ways.
>

Streamlines things, too, on the data consumer end.


> In Mass, we have speed limit tags on almost all legal roads.  To me,
> that seems like the most straightforward approach, even if there are
> also defaults.
>

I tend to agree, also makes it unambiguous where a smaller jurisdiction has
a different default than the one it is inside of, especially if there's
weirdness where the smaller jurisdiction is higher than the larger one for
some reason.


> If the general defaults are intended for routing, that seems more or
> less ok.  If they are intended to actually provide speed limit guidance
> to drivers, I'm opposed, at least in jurisdictions where they aren't
> strictly reliable.


AFAICT, the only places that have huge, state-or-national default limits
that don't get too messy to map as default on an area would be the EU,
everywhere else doesn't seem to be anywhere near as organized on a large
scale.
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