My Kiddo Will NOT Be a Bone Head Driver

Sometimes people make me mad. Ideally, I have the chance to tell them what they have done and how it makes me feel. Other times, though, I am driving, and I don't have the chance. Sometimes drivers are jerks and cut me off or do something else incredibly stupid like come to a complete stop before turning into the turning lane. Sigh. Sometimes, however, drivers do something so repulsive that I have to fight the urge to follow them, wait until they get out of their car, and yell at them. Today was one of those times.

I was behind a car that was spewing trash like a tree drops leaves in a wind storm. First, something small and green popped out from the side of the car. I wasn't certain that the driver was littering, until the next thing flew out the window. Then there were a few more things that also looked like they had come from the same place.

Since I had errands to run and wasn't interested in being arrested for stalking, I opted not to follow the jerk to his destination and give him a piece of my mind. Instead, I honked my horn and shook my finger. I'm lucky he didn't show me his finger.

Would it be totally out of line for me to make a sign that says "I saw you litter, you jerk!" ?
Or I could do this: *caution, adult language http://www.mentaldischarge.com/articles/Drive-By_Road_Rage_Signs or http://www.amazon.com/Shticks-The-Original/dp/B001GRIY7M although, if I have to fiddle around deciding which one to hold up, it's not really worth it. Maybe I need to choose the issue that bothers me the most and stick to one sign.

When I'm in the car with the kiddo and another driver makes me mad, I do my best to explain to her what the problem is. If the only criticism I come up with is "that guy is a bone head", well, then maybe I need to chill out. (But really, the other guy usually is the bone head.)