Conn. Gen. Stat. § 23-26a

As used in sections 23-26b to 23-26g , inclusive, “all-terrain vehicle” means a motorized vehicle, not suitable for operation on a highway that (1) is not more than fifty inches in width, (2) has a dry weight of not more than six hundred pounds, (3) travels on two or more tires specifically designed for unimproved terrain, (4) has a seat or saddle designed to be straddled by the operator, and (5) has an engine with a piston displacement of more than fifty cubic centimeters.