Sorry for my ignorance in this question but its been awhile since I've been on the road in patrol:

Scenario: S observes C driving fast. S pulls C over using red lights, blue lights, and wig-wags. S is volunteer fire fighter in personal truck equipped with emergency lights. S scolds C for driving fast. C gets wise and asks for identification. S never claims to be police nor is he wearing anything indicating any kind of office. His reported role is to pull C over and give him a piece of his mind.

Impersonating?
Unlawful Restraint?
Inproper use of authorized emergency equipment?

Sounds like a lay down Impersonating a public servant.

Thank you.