N.Y. Vehicle & Traffic Law § 2281
For the purposes of this article: 1. (a) "All terrain vehicle" or "ATV" means any self-propelled vehicle which is manufactured for sale for operation primarily on off-highway trails or off-highway competitions and only incidentally operated on public highways providing that such vehicle does not exceed seventy inches in width, or one thousand pounds dry weight. Provided, however, this definition shall not include a "snowmobile" or other self-propelled vehicles manufactured for off-highway use exclusively designed for travel on snow or ice, steered by skis or runners and supported in whole or in part by one or more skis, belts or cleats which utilize an endless belt tread.