It is a prerequisite of Mass Production.
The first practical Automobiles were developed in the late 19th Century, although experiments with steam-powered wagons had been carried out over one hundred years earlier. The critical invention that made the Automobile a success was the internal Combustion engine. This relatively small but powerful engine could be mounted within the frame of the "horseless carriage" and drive the wheels. The Automobile had a tremendous impact on the economy and lifestyles of the rich Western nations, and it also revolutionized warfare. Armed and armored Automobiles, known as tanks, became a dominant weapon on the battlefield.