I have used a way as the "via" member in the relation successfully using mkgmap, so at least one renderer understands a three-way, no node U-turn. As far as splitting ways, only ways that are separated by a median (open or closed) should be seperated into two ways on the map (note that two-way left turn lanes and a single set of centerlines is not a median for purposes of mapping).mapping). For u-turns on a single way, using the same member entered into the relation twice for both the from and the to members, with a via node should work.

I have used a way as the "via" member in the relation successfully using mkgmap, so at least one renderer understands a three-way, no node U-turn. As far as splitting ways, only ways that are separated by a median (open or closed) should be seperated into two ways on the map (note that two-way left turn lanes and a single set of centerlines is not a median for purposes of mapping).