What do I do about children haring me?

The story went like this. It was yesterday at about 2:00 p.m. and I was driving. I was on the road and I slow down as I see four black children crossing the street (J walking). Well eventually I reach a stop, and one of the kids who looked about 11 to 13 years old was on his bike staring me down and saying stuff under his breath. I had my windows rolled up so I couldn't hear him, and I could read his lips saying some F words and B words. He was also giving me a mean look and I was just quizzically looking at him wondering if he was directing his foul language to me (if he were to be swearing) or just singing some good ol' rap song. Anyway after he crossed, he spit on my car (which hit my tire) and flicked me off. I was so angry at this point, I didn't know whether to step out and discipline him myself, or tell his parents. I figured his parents wouldn't have a least care. Anyway, I also wondered if calling police would make any difference, but I figured these young hooligans would just run away. So anyway Yahoo!ers, what should I do next time something like this happens?