(at around 1h 13 mins) The black and white commercial featuring Sarah Jordan wasn't shot specifically for the movie; it is an actual commercial starring Scarlett Johansson.
Robert S. Fiveson, director of The Clonus Horror (1979), brought a copyright infringement suit against DreamWorks and Warner Brothers. The lawsuit cited almost one hundred points of similarity between "Clonus" and this film, and the court ruled that Fiveson made a prima facie case for infringement. Before the case could go to trial, DreamWorks settled with the plaintiffs for an undisclosed seven-figure amount.
The original script was set one hundred years in the future, but they kept bringing it closer to the present for budgetary reasons.
Michael Bay drove behind a flatbed truck carrying train wheels on the highway leaving Palmdale, and, noticing how dangerous it looked, was inspired to create a destructive chase scene involving one.
They shot the city sequences in Detroit because it's rarely used and because "they were nice enough to shut down eight blocks" for the shoot.