Ron Howard actually went to school with Rene Russo, and admitted in an interview that he had a crush on her, but was far too shy to ask her out. Russo later admitted that she also fancied him in school, but she never acted on it.
Jimmy Shaker is seen carrying 2 and 3 handguns. This is a common practice for NYPD, as in the early days, they were forbidden to use a speedloader for their revolvers so they also carried their backup guns and off duty guns in addition to their primary handgun.
(at around 1h 8 mins) Bryce Dallas Howard makes a cameo as a girl who nearly gets run over when Mel Gibson's character runs an amber light.
Ray Liotta declined the role of Det. Jimmy Shaker because he took issue with the film's theme of violence against children.