Abused on the road for no fault of mine.

So yesterday I was on my way home and while taking a right turn at a junction, a guy came from the wrong side and banged into my car. He wasn't wearing a helmet, and seemed like one of these local area boys. He banged on my window, threatened me to roll down my windows and abused me in all filthy words and made me feel like it was my fault. Since I was alone I didn't want to make a scene, didn't roll down my windows because I wasn't sure what he was capable of. What was even disturbing is that not a single person questioned him, untill one cab driver asked him to stop his nonsense and go away. How do you deal with such imbeciles on the road? No cops around to complain and I was completely in panic they way he was abusing me and targeting me when he is in the wrong.