Have a look at this area in JOSM: <http://www.openstreetmap.org/index.html?mlat=49.208673539416914&mlon=12.668000677366676&zoom=18> There is a roundabout there consisting of 4 different ways. I can't join those ways, JOSM says they could not be merged into a single string of nodes. I don't see why. Maarten