The automobile industry has played a key role in twentieth-century American society. It became the backbone of the new consumer goods-oriented society during the 1920s and contributed to one-third of all employment in the country by 1982. The automobile industry was also the lifeblood of the petroleum and steel industries. After World War II, automobile production rose in Europe and Japan and by 1980, it was a global industry.
Modern automobiles are powered by a water-cooled piston-type internal-combustion engine. This power is then transmitted to the front wheels or all four wheels. Air-cooled engines are used in some automobiles, but they are less efficient than liquid-cooled engines. Some automobiles have the engine mounted forward of the rear wheels to improve weight distribution. Automobiles can be classified into two main categories: sport and economy. Motorcycles are considered the most fuel-efficient vehicles, achieving up to 50 miles per gallon, while the average car can only manage 10 miles per gallon.
Motorcycles are often classified as automobiles, but the legal definition of motorcycles is murky. The definition of motorcycles differs from that of automobiles, so it is important to clarify your understanding of this distinction. While motorcycles are auto propelled and often used for transportation, motorcycles are not considered automobiles by many.