With regard to CB channels: Truckers use channel 17 on the west coast and generally speaking from Ariz. east they use channel 19. As far as the emergency channel, I have never heard any emergency communication on any channels but then again I don't try to use the CB for emergencies but rather use the cell phone. It has been reported that channel 13 was the channel for RVers but in 20 years I have never heard a RVer on the channel. I use channel 17 and 19 for road, traffic conditions and location of "Bears" but my Valentine Radar does a great job of helping me drive safely or avoid getting any speeding tickets:):):)