So a man wanted to play police officer and pull people over on the road. Well he pulled over the wrong car. It was an unmarked car that contained two highway patrol officers. https://amp.usatoday.com/amp/786758002 Some people want to play dress up and act like police. Maybe they like imposing authority onto other people, a psychological component to their personality (one that many who in fact choose to enter law enforcement possess). Or maybe it fulfills some fantasy. I don't think this man had any ill intentions, but there have been cases of men impersonating police officers to rape women. Just goes to show when someone approaches you who looks like police, you can't always be completely sure.
In HS I had a friend that work for a mechanic part time and he was given a police car to test drive after some repairs had been done to it. He went up and down route 35 pulling over any friend he could find on the road with full light and siren including myself. Amazingly he got away with it and it did raise his standing at the school greatly for some time.
Former Presidential candidate Mitt Romney also did that, in his earlier years. Impersonating a police officer didn't always use to be illegal. That's just one of the many crimes they've added to the law books over the years.