Hi Michel,
When routing with a mkgmap (svn rev. 907) generated routable map, my nüvi gets seriously confused about this area:
http://www.openstreetmap.org/?lat=47.44357&lon=8.69386&zoom=17&layers=B000FT...
* Two of the motorway-links there look like residential roads on the device * way 4987473 is labeled '67' although there is no such ref or name for this way in the OSM data * The way 10864230 (highway=secondary) is labeled "Ramp" on the garmin
Another area that shows similar problems:
http://www.openstreetmap.org/?lat=47.479862&lon=8.704816&zoom=18&layers=B000...
Again, motorway link 4248871 is unnamed in OSM, but on the Garmin, it is labeled with the name of a nearby river (Töss, id: 4255496). It also gets rendered like a residential road.
As a side effect, in those two areas, the garmin omits some turn-instructions (e.g. to take the ramp to the motorway).
I also noticed that when taking a different route as the one suggested by the device, it takes much longer for the garmin to recalculate the route than with the built-in map.
Are these known deficiencies?
I don't recognise them as such. Are you converting to mp format or processing the osm file(s) directly? If the latter, are you using the default style files? Cheers, Mark