Yes it is but you can not talk to them. Its called "skip". Radio waves that bounce off the atmosphere and then return to earth.
19 is the common channel for truckers. ,18,20 get some traffic as well. When 4 wheeling, I use CH4, others use 16(4x4). If you want to talk to someone specific you see on the road call them on 19 then switch to another agreed on channel.
My radio typically stays on 4 and gets turned off when not in the bush or convoying with friends.