The Cadillac ATS is a four-door, five-passenger compact luxury sedan designed, engineered, manufactured and marketed by General Motors. General Motors developed the ATS at the General Motors Technical Center in Warren, Michigan, United States. GM assembles the ATS at the Lansing Grand River Assembly plant in Lansing, Michigan, United States. The ATS is Cadillac's smallest vehicle, slotting into the Cadillac vehicle line under the larger Cadillac CTS