[OSM-talk] Divided roads proposal

[Anthony]

On Fri, Dec 4, 2009 at 8:27 AM, Steve Bennett <stevagewp at gmail.com> wrote:
> Ok, I've uploaded 10 examples of median strips here:
>
> http://wiki.openstreetmap.org/wiki/Talk:Proposed_features/Divided_road#Images_for_discussion
>
> Hopefully we can use them to discuss whether this proposal is helpful, and
> what alternatives there might be otherwise.

1, 2. Dual carriageway
3. Assuming these roads eventually divide, I'd personally use a dual
carriageway, however, this is disputed.  Currently, this could be best
handled with three highway areas, with the highway in the center
marked as access=no (in jurisdictions where crossing that gore area is
prohibited, I can't tell the jurisdiction from the photo).  In
jurisdictions where those painted gore areas mean "use a lot of extra
care when crossing", this could be mapped as a single way.
4. Looks easiest to map accurately as a highway area with several
barrier=* areas.  Are we allowed to make highway multipolygons?  Or
just ignore it, as it's so insignificant, and use a single way.  I
don't see any other markings in this photo, if there are signs, I've
ignored them because I can't see them.  I see no lane markings, so it
fits with "area=yes, in the context of roads, indicates that the area
has no street lines within it".
5, 6, 7, 8, 9, 10. Dual carriageway

Regarding 3, hopefully we can eventually get a solution for directed
highway areas, whether that means using both an area and a way, or (my
current preference) using a relation with role=left, role=right, and
role=outer, then oneway=yes to represent that vehicles must travel
forward with respect to the left and right ways.  However, they would
really be unnecessary here, because both the incoming and outgoing
ways would already be oneway=yes, so there's basically no way a router
would direct you backward on them (I guess it might if you asked for
directions from one spot to another within the same area!).