Damon Wayans, jr. is the son of Damon Wayans who played opposite Bruce Willis in The Last Boy Scout. In the movie Wayans also did detective work alongside Willis although he wasn't one.
Luke Greenfield got the idea of the film when a costume designer brought him an authentic LAPD uniform to wear for Halloween, which resulted him gaining high confidence.
The frequency shown (53.98 MHz) on the main characters' radio scanner in their fake cop car when they "respond" to the domestic violence call is actually used by the amateur radio service.
When Jake Johnson's character is practicing self defense techniques with the kid he is wearing Sergeant's stripes. In the very next scene while out patrolling his shirt does not have stripes. When he is out on patrol the following day he has been promoted to Sergeant.