The Movie: The T-Rex's footsteps cause massive impact tremors from afar, giving everyone in the parked cars lots of time to freak out over her approach. Once she escapes, Grant instructs as many people as he can to remain motionless, because her vision is based on movement.
Real Life: Imagine being able to hear your enemy from miles away! Those impact tremors would sure make T-Rex an unsuccessful hunter. Given the tyrannosaur build, it's unlikely a Rex could make that kind of noise if it tried. Oh, and if you ever come across a T-Rex, don't stand still thinking it will lose you. This detail was added into the movie as a plot point to make the human escape seem a little more plausible, and was justified by the idea that some reptiles do have motion-based vision. But it's likely tyrannosaurs could see motionless prey just as easily as other carnivores of the Cretaceous. Even on the off-chance they couldn't, you can bet they'd smell you right away, as recent research has revealed that T-Rex likely had an incredibly keen ability to track the scent of its prey.