[Tagging] [OSM-talk] A warning about gates and other barriers

[Ben Laenen]

Richard Fairhurst wrote:
> Wow. The OSM wiki never ceases to disappoint with its limitless provision
> of confusing, badly written, half thought-out crap.
> 
> So we have a page that says "implies access=no" and then happily
> contradicts itself by saying "an entrance that can be opened or closed to
> get through the barrier". That's "can be opened" (access=yes), not "can't
> be opened" (access=no).
> 
> It's probably just as well the wiki documents, not defines. And given the
> vast preponderance of highway=gate nodes within (say) highway=footway ways,
> the wiki docs look pretty unambiguously wrong.
> 
> Anyway, follow-ups to tagging at .

The problem with it as I see it is that it makes use of access tags to define 
what can pass. I'm pretty sure that right now a lot of barriers are only 
tagged with bicycle=yes while at the same time there's nothing at those 
barriers that prevent access to mopeds or even motorcycles, or horses.

So for barriers we want something that describes the physical state of the 
barrier (and specifically how big the openings are). And this should be 
something general like "pedestrians only" (and this would exclude e.g. 
pushchairs), "small traffic" (pedestrians, bicycles, mopeds, etc), and "wide 
traffic" (cars and everything else), and an extra limitation on horse drivers 
and some other ones (needs to be thought out first obviously). After all, if 
you get off your bicycle, you become a pedestrian, but some of these barriers 
don't allow you to get a bicycle to the other side even with a lot of 
acrobatics, something your bicycle router might be interested in if you tell 
it to allow small parts to be walked next to your bicycle.

And if there are explicit signs limiting the traffic to specific vehicle 
classes, *then* you should use access tags.

Furthermore, in many cases, extra tags aren't really needed anyway on the 
barrier nodes, the tags on the paths or roads behind the barrier usually have 
all the needed tags. If a gate is always closed then a road behind it may 
often be access=private already.


So my idea: define sensible physical defaults for each barrier type 
(barrier=bollard blocks wide traffic for example). And if it's not really 
possible to make a good default (like barrier=gate) then by default allow 
everything that's allowed on the highways at both sides of that gate.

Greetings
Ben