I was ten years old growing up in a rural state famed for its narrow, steep, twisty roads when the first plans for the Interstate Highway System were published, and we had the same concerns.
Busses carried 36 pax max, tractor trailers were single drive axle, single trailer axle, the longest trailers were 36 feet, and sleeper cabs were unheard of. Detroit cars were just starting to grow, "I love 57 Chevies, I think they do it up right!" Old Angie Barofio, my dad's mechanic, would roll over in his grave if he saw the monsters that prowl the Interstate today.
Cheers,
Wes