text: I've used an OSM-based map on a Garmin device to route between Aspen and Glenwood Springs. It tried to choose a way over Independence pass (wrong direction...) and after I drove on CO82 switched to the base map data...
  
  Last year I thought that I fixed a "hole" in CO82 but the issue still exists. Now it seems to me that the highway data switching between "two lane data" and "one lane data" (e.g. at the marked point) might be the issue. Actually there are many such transitions along the route