According to Oregon law, an ATV is any motorized off-road vehicle, except for a snowmobile. ATVs are divided into four classes.
- Class I ATV has a maximum width of 50 inches, a maximum dry weight of 1,200 pounds, three or more inflatable tires, handlebars for steering, and a seat designed to be straddled by the operator. Also known as quads and 3-wheelers.
- Class II ATV weighs more than or is wider than a Class I ATV and is not a Class IV ATV. Also known as 4x4s and includes trucks, Jeeps, SUVs, dune buggies, and sand rails.
- Class III ATV is an off-road motorcycle (ORM or OHM) with two tires.
- Class IV ATV has a maximum width of 65 inches, a maximum dry weight of 1,800 pounds, four or more inflatable tires, a steering wheel for steering, and non-straddle seating. Also known as side-by-sides or UTVs.