Because, IME, Americans can't drive. They do vaguely operate a car when drinking coffee and texting, whilst switching lanes constantly just to be one car further ahead of the rest of the pack who are already doing 75 in a 55 limit. But, whatever, the Interstates are a reasonable way of getting from A to B ... if a little bit scary!

I like to keep a bit of safety distance from other veee-hickles. Do that in the US, and there will be 3 cars or a truck instantly trying to fill that bit of space. Curiously, it seems to have got/gotten a lot worse over the last 10 years.