My brother in law does this. Gets so close that you can't see the rear tires of the car ahead, going 80+ mph. He's been in multiple wrecks, including one where he totaled his custom BMW and almost died. He blamed the other driver (somewhat reasonably, they were drunk, but he was driving like a psycho), and refuses to change any of his driving habits.

He also used to street race in Florida, with his family in the car. No, they did not consent to it, they're just too scared of him to say anything.