The all-terrain vehicle (ATV) is defined by the American National Standards Institute (ANSI) as a vehicle that travels on low pressure tires, with a seat that is straddled by the operator, along with handlebars for steering control.
As the name implies, it is designed to handle a wider variety of terrain than most other vehicles. Although it is a street-legal vehicle in some countries, it is not street legal within most states and provinces of Australia, the United States and Canada. 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 slower speeds.