Awesome, Dear Boy: Why William Petersen took the role; he loved the idea of playing a rule-breaking Rabid Cop. This also happened during the shoot; before filming the sequence where Chance runs atop the airport people-mover, the facility's police told the crew not to do the proposed stunt as such a thing in an airport is an illegal violation. However, Petersen REALLY wanted to do it as he felt Chance would in pursuit of a suspect; they quickly did the stunt as soon as the police left the area.
If you watch a double-bill of this and Repo Man, you'll notice that both films feature (a) cinematography by Robby Müller and (b) car chases in the LA storm drains.
Enforced Method Acting: During the wrong-way chase scenes on the Los Angeles freeway, Vukovich's panicky reactions were genuine. According to the DVD commentary, this was more in effect when Petersen was driving instead of the stunt double.
Name's the Same: Modern-day viewers see "Robert Downey" in the credits and wonder why they don't spot Tony Stark - when the Downey in question is his dad.
Throw It In: When Chance was slamming the briefcase against the pillar, it wasn't supposed to break open. When it did, and the phone book to simulate its weight in money sprung free, Petersen continued to roll with it.
Chance: That's real funny. *hurls phone book at agent*