Suppose you were driving along with your windows down, or in a convertible, or with your sunroof/moonroof open, and I drove past you. Without looking, without paying any attention whatsoever, I toss a rotten tomato out of my car, and it lands in yours. How would you feel? How would you feel if people were carelessly tossing rotten tomatoes out of their cars all day and all night long, so that the road was littered with them? How would you feel if you could see them piling up along pathways as you walk around town?
How would you feel if the tomato was on fire when it landed in your car?
People casually toss lighted cigarette and cigar butts out of their cars every day. One landed in a co-worker's car, leaving an inch wide burn mark. You see cigarette butts piled up at the side of the road. Unlike tomatoes, these things can take months or years to break down.
If someone chooses to pollute their lungs, wreck their health, and stink like an ashtray, go ahead. But don't presume that the debris of your addiction, the used cigarette and cigar butts, are not litter. They are litter, they stink, they are still smouldering, and they can start fires. Keep them to yourselves, dispose of them correctly, and NEVER throw them out of your car!