Dear Mr. Steve

Don' t worry, you did nothing wrong while driving. The only "wrong" you did was to show your anger and indignation in the wrong way. Your salutation has a sexual context and in these countries anything with a sexual context is highly inflammatory. You might wanty to avoid that in the future As well as the words pig and dog. Next time call him an idiot.
You were dealing with someone who regarded themselves as infinitely superior to he rest of mankind, and you are and will certainly not be the only one who gets in this gentleman's way. The best thing to do is be thankful you came out of this safely breathe deeply swallow the insult and be on your way. You handled the situation well by going to the traffic division. These kind of people are highly frustrated by the demands of their everyday life and not even small children are safe from their wrath.

Stay calm, don't worry about any follow-ups they usually don't come. They just like to scare and intimidate. For future emergencies keep some hairspray or deodorant beneath your car seat for serious emergencies. NOT for intimidations.

Birgit