If ATV = All Terrain Vehicle...why is a dirt bike not considered an ATV? Last I checked, I can take my bike through rougher terrain than a 3 or 4 wheeler. To me, the definition of an ATV should be any vehicle operated by one person, who straddles the seat and can traverse many different types of terrain. And what about people that call a quad a bike...that pisses me off. A bike has 2-wheels...end of discussion! Wikipedia says: The term "All-Terrain Vehicle" or ATV is used in a general sense to describe any of a number of small open motorized buggies and tricycles designed for off-road use. However, the American National Standards Institute (ANSI) defines an ATV as a vehicle that travels on low pressure tires, with a seat that is straddled by the operator, and with handlebars for steering control. By the current ANSI definition, it is intended for use by a single operator, although a change to include 2-seaters (in tandem) is under consideration. The rider sits on and operates these vehicles like a motorcycle, but the extra wheels give more stability at slow speeds. Although typically equipped with three or four wheels, six-wheel models exist for specialized applications. Engine sizes of ATVs currently for sale in the United States (as of 2007) range from 49cc to 760cc and 49cc to 400cc for two stroke ATVs. What do you think?