Yah, but I think you have to be a little careful with that site; meaning this: usually for it to be harassment it has to be repeated. A stranger chasing you because of road rage is kind of on the fence. They would have to be repeatedly chasing after you, and you specifically, for like days and days. If it's kind of a passion in the moment thing, like road rage, then depending on what they do the cops will most likely give them a warning, and I doubt one could go after them legally. If they are talking about killing you and your family, again, kind of on the fence. I think they have to demonstrate actual intent along with the words, like if they came after you with a gun or knife or something. Otherwise, it's just words, and it could really go either way. If they are like "I'm sorry, I didn't mean it, I was just really worked up" the case would probably get thrown out. There has to be something compelling in order for it to turn into a case. Road rage is probably one of those gray area type things where it gets thrown out/not pursued the majority of the time. Now, if the guy continues to follow you and really feel unsafe, of course always call the police. Or drive to the police station if you are near it. Not sure anything will really happen to the other person though.
*Note: I'm not a lawyer, I just play one on TV.