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Vincent's primary weapon of choice in the movie is a Heckler and Koch USP .45 caliber, as stated by Mann in the commentary. He also uses a Ruger MKII .22 caliber long-rifle handgun with integral sound suppressor, for the hit in the jazz club. For the final part of the film, he uses a 9mm Smith & Wesson 5906, that he takes from a security guard he kills.
According to Michael Mann, Vincent is a man able to get in and out of anywhere without anyone recognizing or remembering him. To prepare for the movie, Tom Cruise had to make FedEx deliveries in a crowded Los Angeles market without anyone recognizing him.
Tom Cruise really fell when he stepped on the office chair. Michael Mann liked the anomaly so much that he left it in the film.
Australian screenwriter Stuart Beattie was only seventeen when he took a cab home from the Sydney airport. It was on that ride that he had the idea of a homicidal maniac sitting in the back of a cab, with the driver nonchalantly entering into conversation with him, trusting his passenger implicitly. Beattie drafted his idea into a two-page treatment. Later, when he was enrolled at Oregon State University, he fleshed it out into his first screenplay. Titled "The Last Domino", he put the script away, taking it out occasionally for revisions and re-writes over the following years.
Javier Bardem only spent two days filming. However, he spent several months learning to speak English with a Mexican inflection for the role.
One of the big reasons why Michael Mann chose to make 'Collateral' was the way Stuart Beattie's script captures an entire story in a very short period of time. The whole movie is "like the third act of a traditional drama." He likes how it doesn't go backward to offer more detail into these characters' lives, and instead we're just catching them at this moment.
Michael Mann: [military training] Vincent's methods of assassination show that he's undergone some sort of military training.
Michael Mann: [white supremacists] If the viewer observes carefully during the scene where Max is being robbed by the long haired derelict, a small and faint swastika is visible on his upper left cheek. Mann has also featured white supremacists in Heat (1995) and Miami Vice (2006).