[Tagging] maxwidth vs. maxwidth:physical vs. width
lauri.kytomaa at aalto.fi
Mon Feb 16 10:16:44 UTC 2015
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.
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