If an off duty officer was conducting a traffic stop, they were carrying out duties in their department vehicle and potentially uniform, they should be following department policies.

On or off duty doesn’t matter. Yes they are.

As you describe the situation it sounds like he didn’t write you a ticket or file charges or call anything in etc. It literally just sounds like you pissed him off and he was being an asshole. I am guessing (not a lawyer) that if someone tells you their profession is a police officer they are not somehow bound by law to provide you all the details of their employment.

Well, should they be trying to act within the scope of their employment when off-duty (i.e., directly intervene via road rage) unless there is such a grave threat to the health and safety of the public or there is a clear, dangerous crime potentially being carried out? Improper procedure? And I think anyone who would follow a stranger's car into a parking lot at night just to verbally berate them may not be in their right mind. I should have asked if they had anything to drink that night or were taking medication or controlled substances.

But, that is the distinction I am trying to point out and make for you. Nothing you described sounds like anything he did was in the scope of official business. This sounds to me like it was very specifically NOT in the scope of official business so he is not required to provide you any information. Him being an asshole and acting crazy is totally irrelevant to your question. If he was not on duty and did not ask for your id and did not try to ticket and did not try to charge you than… NO, simply mentioning he is a police officer does not mean he is bound by law to provide you his badge number and name, get it? Had he done anything within the line of his duty than and only than YES.

Ridiculous encounter either way. Absolutely ridiculous. Too much vigilantism and vigilante-like tactics.