Contrary to popular belief:
Sucking up to higher ups isn't what gets most people promoted, that's why we have voting. One SGT or one LT doesn't carry a vote, being a good cop gets you promoted.
Secondly, from what I see, higher ups do a great job RPing with civs, but the fact remains over half of civs refuse to RP when they get caught. Then when they say, "just give me my ticket! I'm not explaining shit!" they feel like they have the right to complain that the cop did just exactly that and didn't rp with them.
Be a good cop, RP well, train cadets well and you'll get noticed. It seems like the cops who believe that fact always tend to end up promoted quickest.