thats life mate. normal id say.
if you got the plates, call up the police station that the car was patrolling in and make a complaint (pretty much guaranteed to do nothing/go no where/ get laughed at). cops have each others back, if u were a cop u probably wouldnt dob in a fellow worker for something not worth dobbing (ie some stupid road thing), unless you disliked him/her.
if it did go anywhere, and he did hear back from it, it would probably only make the cop angry and anal rape the next person he pulls over.