I think that if he never identified himself as a police officer, never showed a counterfeit badge, and never claimed to be placing anyone under arrest, he didn't do any thing that could be construed as impersonating a police officer.
It sounds as if the case would have to revolve on his demeanor. If walking with a swagger is impersonating a police officer, then we're all in big trouble. Showing someone a driver's license is evidence of NOT impersonating a police officer.
Boat: a large, heavy, older American full size automobile, usually low milage. example - 1957 Chrysler Imperial four-door sedan.