I had a guy throw a cup of something at me on my ride to work a little while ago. I took down the licence number and called the cops. Once I told the cop what happened (after waiting for about an hour) he asked how far do I want to take it and that their wasn't much they could do since thier was more than one person in the car. Hopefully if this driver does something again there will be a file or something. I like cops, and through my job work with them sometimes; but it sure was frustrating hearing their wasn't much that they could do (though I do understand their point).
Just keep thier licence number and the name of the cop who took your information. Hopefully the cop is true to his word and pays the guy a visit.
In my incident I did find out where the guy lives and have been thinking of naughty things to do to his car (just don't tell anyone

).