Houston leads the USA and, and I would assume the world in parking, with an estimated 30 parking spaces per resident.

Office parking lots in Houston during work hours are, on average, 30% empty.

I have to wonder how much of the city overall is used for cars -- roads, highways, and the "buffer" land surrounding them (like the land in and around a highway interchange); parking lots and their access streets; businesses dedicated to servicing cars, like gas stations...

It's probably a lot.