I keep a trash bag handy for all trash that is not food (the bag is at nose level of a trash-picker) or on fire. My butts go into a self-extinguishing butt kit that hangs on my door. I empty all trash into provided receptacles whenever I stop.
I have taken other truckers to task for littering (it's at it's worst at the back of a truck stop) and "eliminating" behind their trailer. But I am an asshole. Ask anyone.
Brian