Planes, Trains, & Automobiles.

The sheer physical size of America influences how it looks.

Everything is at least a car journey away. (And since you're in a car anyway, there's no reason why we can't just build the next development even further away.)

Teenagers get a driving license on their sixteenth birthday, and everyone has a car, so you build with that fact in mind. Hence, Drive-Through Restaurants, Drive-Through Banking, Drive-In Movies, even Drive-Through Weddings. Shopping Malls consist of large brick-shaped buildings, set well back from the highway to allow for the huge parking lots, and finding parking is itself a permanent quest.

All of which caused me no end of problems when I first got here. Public transport is next to non-existent, and the natives looked at me as if I had two heads whenever I told them "I walked". I'm even told there are parts of California where you can be arrested for walking.

Better Keep on Trucking.