Wages of truck drives in the USA are well over 100 billion dollars annually. Wages of taxi drivers in the USA total over 4 billion dollars annually. Cost savin

Wages of truck drives in the USA are well over 100 billion dollars annually. Wages of taxi drivers in the USA total over 4 billion dollars annually. Cost saving is the reason for the rapid replacement of the human-driven vehicle fleet. It took only 20 years, 1900-1920, for human-driven automobiles to replace horses - which was a bigger change with regard to infrastructure.