[Tagging] Turning circle with island or turning loop (was Re: (Mini)Roundabout: examples

Martin Vonwald imagic.osm at gmail.com
Mon May 14 16:02:07 BST 2012

> It looks good to me, except for the last example of a "turning loop"
> as I've been calling it. We're going to have the same problem with
> this one, because they are abundant and very small, thus people will
> likely mis-tag it rather than drawing a tiny loop. When I fixed up
> some of westendguy's mini_roundabouts, he often used the tag with
> these cul-de-sac turning loops, and I tagged it as junction=roundabout
> and note=turning_loop so it could be checked/fixed later. Checking
> taginfo, someone else tagged these as highway=turning_circle with a
> FIXME [1]. Others have indicated they do highway=turning_circle and
> traffic_calming=island.
> The first question is if these can be considered a roundabout if there
> is at least one driveway that connects to it (this would be my
> choice), as is most often the case. If not, then we need some way to
> differentiate these from highway=turning_circle and
> junction=roundabout, though I'm not sure what tag is best.
> -Josh

Correct - this needs some simplification just like allowing
junction=roundabout on a node for small roundabouts. But I would
really like to update the page before we talk about this, because
otherwise the update won't be any time soon ;-) As it is never wrong
to map them as a loop I don't think of this as a show stopper? Do you
agree on this?

Now back to the problem:
* highway=turning_circle is not correct, because a turning circle
should not have an island for the same reason why a mini-roundabout
should not have one (-> large vehicles). Using traffic_calming=island
is therefore a contradiction, although I'm a little tempted to go this
way. But right now I'm resisting myself ;-)
* junction=roundabout is not correct, simply because they are no
roundabouts (one-way, right-of-way).

The longer I think about it, the more I'm asking myself: do we really
need a tag for this? If someone doesn't want to map it as loop, why
not simply end the road without any additional tag? What information
are we missing then, that we are not missing if we use a single tag
instead of a loop?


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