[Talk-GB] Roundabout, ways and relationship policies

[Richard Mann]

I think that we let taggers decide whether it's a roundabout or not (to me
the defining feature is that you perceive it as a single junction, rather
than a series of connected junctions in a one-way system, usually because
there's nothing in the middle, however there's quite a grey area, and
perceptions will vary among users, especially when there are lights).

Question really is how do we tag that and does splitting it cause any real
problems.

I think most purposes are served by putting junction=roundabout on all the
ways in the circulating carriageway (including any shortcuts in the middle).
That way routers will know that they're sending someone onto a roundabout.
And renderers who want to use a roundabout symbol can do a reasonable job
without pre-processing for small and medium roundabouts (you just put the
symbol on each and every node). I could see it might be helpful to give
large roundabouts (maybe >100m diameter) a distinctive junction= tag (or
just treat it as a one-way system).

But I can't on the face of it see any major need for roundabouts to be
single ways, or any pressing need to put the component ways into relations.
Unless anyone else can think of one?

Richard
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