The driving before the interstates happened on dirt roads, country roads, or paved roads in crowded city thoroughfares, with top speeds of less than thirty mile

The driving before the interstates happened on dirt roads, country roads, or paved roads in crowded city thoroughfares, with top speeds of less than thirty miles an hour. Automobiles in the '20's sat tall, with lots of interior room (even the low-end Model T had plenty of vertical space); sedans in the thirties began the trend towards lower profiles which continued up through the sporty road cruisers of the fifties. Those sleeker, lower profile designs would have been pointless without highways. I don't think it's an entirely unlikely explanation.