Martin Vonwald wrote:
>My understanding so far:
>* width: this is the actual width of a feature
>* maxwidth: this is a legal limitation; nothing wider than the given value may 
>use the feature
>* maxwidth:physical: according to the wiki page: a physical limit

The width of the vehicle that could use the way can be wider than the way 
itself, even if it depends on the conditions whether they're allowed to. For an 
example, a way in a park might be, say, 2 meters wide, but if there's just 
grass around it, a maintenance or construction vehicle or what ever could use 
that way even if all wheels don't fit on the "intended" surface (supposing the 
soil isn't too soft). Or a cycleway; the asphalt is 2.5 meters (width), but if 
there's no guard rail, a police van can use it even if they're wider than that 
(with mirrors included) - but if there's a guard rail on one side and a hedge 
on the other side, the physical maximum width could be just 2.6 meters (numbers 
off the top of my head.)

Another likely case is when the width of a gate is, say, 3 meters (the whole 
structure), but the gap between the sides is only 2 meters: width=3 + 
maxwidth:physical=2

Less likely cases could be a road with trees next to it, such that the road is 
6 meters wide, but for a section the branches limit the physical width usable 
for vehicles to, for example, 4 meters. Or a divider on the pedestrian crossing 
limits the physical width of passing vehicles to x meters, yet the road is more 
than 2*x wide.

I haven't looked up if the maximum legal width sign refers to the actual width 
(with mirrors etc) or to the width stated in the vehicle's registration 
documents. Nevertheless, a road with a width of 2.6 meters (e.g. a narrow old 
town alley or a courtyard entrance) may, or may not, physically allow a vehicle 
with a width of 2.55 m + mirrors to pass.

It's true that good example photos would be a nice touch to the documentation.

Considering the possibilities of different "special loads", with the 
transported object surpassing the width of the vehicle, should IMO be beyond 
the applicability of these tags as such; a 4 meter wide load supported 2 meters 
above the road surface could or would, for example, just go over the pedestrian 
crossing middle island traffic signs, whereas a four meter wide harvester 
couldn't navigate that location at all. I don't yet have an idea how that 
should be best spelled out in the wiki.


--
Alv


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