Complex sentence: The Interstate grew quickly over the next few decades, along with the automobile industry, allowing a new-found mobility that permeated ways of American life and culture as a large share of the population could travel long distances in their own vehicles at their leisure.
Split into simpler sentences: The Interstate grew quickly over the next few decades, along with the automobile industry. People were able to travel much greater distances in the same amount of time, and this new-found mobility permeated ways of American life and culture as a large share of the population could travel long distances in their own vehicles at their leisure.