A snowmobile, also known as a sled or a snowmachine , is a vehicle designed for winter travel on snow. It is designed to be operated on snow and ice and does not require a road or trail but most are driven on open terrain or trails.Snowmobiles generally accommodate two people, similarly to motorcycles or all-terrain vehicles (ATVs), though special snowmobiles designed for mountain riding/deep snow travel typically have a aller seat for one person. They do not have any enclosures, except for a windshield, and their engines normally drive a continuous track or tracks at the rear. Skis at the front provide directional control.