The Combat Arms Regimental System (CARS), was the method of assigning unit designations to units of some of the combat arms branches of theUnited States Army, including Infantry, Special Forces, Field Artillery, and Armor, from 1957 to 1981. Air Defense Artillery was added in 1968. CARS was superseded by the U.S. Army Regimental System (USARS) in 1981, although the term "Regiment" was never appended to the official name or designation of CARS regiments, and was not added to USARS regiments until 2005.