Ironically, the burgeoning economy that the interstates helped to create in the world's leading capitalist country carried inescapable overtones of socialism. Any mode of transport requires both a vehicle and a pathway. Railroads, the quintessential free-enterprisers, owned both their trains and their tracks. But Congress built, owned, and maintained the interstate pathways it supplied free to commercial motor vehicles.
Stephen B. Goddard, Getting There: The Epic Struggle between Road and Rail in the American Century (New York: Basic Books, 1994) 193-4.