After reading all of the posts, in reply to your question, it would seem (for now) that there is not clear cut answer. I too have scanned while on road trips only to hear sporadic chatter. I tend to stay on the higher power channels to allow for further simplex communications. Perhaps, with the proper discussion, motivation, and educating people. When a channel is recommended (if ever) for use while on the road, then it can be a mission of the mygmrs community to share the knowledge.