dstrong 

There's a stretch of road I ride where there are no shoulders but there are occasional driveways to move into if there are cars behind me. Most of the time cars will move to the center of the road to get around me if there's enough visibility (sometimes even if there isn't), but occasionally, one will sit behind me, even with me to the far right. As long as they don't honk, I'm fine with them sitting back there...it's their choice. Whenever they do ultimately pass, I usually give them a wave to let them know I appreciated their concern.