Back in the early 1960s, Russia started the development of stronger and heavier ATVs (all terrain vehicles). At this time, most of the the single-unit tracked snow- and swamp-going vehicles in service could not carry payloads of more than 5,000 kg. A specialized design bureau was established with the task of developing a new ATV. By 1985, the development of the Vityaz two-unit ATV had finally been completed. Intensive trials were carried out in extreme terrains and under severe weather conditions in various areas of Russia and demonstrated that the vehicles have a high cross-country ability and load-carrying capacity. They are highly reliable and can be used effectively to transport military equipment in severe climatic conditions in the polar regions as well as in desert areas. The HDT's cross-country maneuverability on low-bearing soils and its capability to carry heavy payloads (about 100 soldiers), combined with its speed and amphibious capability make the HDT-10P the best vehicle of this class worldwide. Both units are made off welded steel-plates. The vehicle's engine is located in the front unit behind the driver's cabin. The torque from a 12-cylinder multi-fuel engine is conveyed to a hydromechanical transmission via a cardan shaft to the final drive units, as well as to the drive sprockets of both units. The tracks are made of four wide rubberized tracks which are reinforced with welded steel parts. The suspension is an independent torsion-bar system with spring support on all rollers. With this unique design, the Vityaz can operate in conditions which are impossible to enter for other ATVs. Its special capabilities include amphibious returns to a mother ship, negotiating ditches and clefts up to 4.0 m wide and unloading of ships offshore if they cannot come close to the shores. The HDT-10P ATVs are widely used by Russian troops in polar regions for transporting soldiers, ammunition, equipment and installation of weapon systems. The Vityaz proved to be very effective and reliable during their service in the Chechen war in 1995. The HDT-10P two-unit vehicle has no weapons and is protected only against small arms fire. It carries some camouflage equipment which can hide it from enemy observation.