Private car ownership is highly restricted. You only have access to a car if you are a party member, are conducting business for the party, or are well connected.
Their society is very localized and travel is restricted(you need a permit to leave your county), trains and bicycles are how you move about if you aren't walking.
Also why the US highway system was built, btw. The president who championed it, Eisenhower, was the commander of US allied forces during WW2. While there were other benefits, his goal was to be able to quickly transport troops in the event of a Soviet invasion.