Art car recent years the festival has been forced to limit the number of vehicles on the playa. As such they have restricted the vehicles that are licensed to what they are now calling "mutant vehicles". There has been some confusion within the Burning Man and Art Car communities over these two terms, with some believing the terms are simply synonyms. According to art car artist and Art Car Fest organizer Philo Northrup, art cars are "street-legal vehicles that have been permanently transformed into mobile sculptures". According to the Burning Man DMV ("Department of Mutant Vehicles"), Mutant Vehicles are "'art on wheels':
Technical, Administrative and Supervisory Section Trades (NUGSAT) in 1981, the National Union of Sheet Metal Workers, Coppersmiths, Heating and Domestic Engineers in 1983, the Association of Patternmakers and Allied Craftsmen in 1984, the Tobacco Workers' Union in 1986, and the National Society of Metal Mechanics in 1987. In 1988, it merged with the Association of Scientific, Technical and Managerial Staffs (ASTMS) to become the Manufacturing Science and Finance Union (MSF). MSF in turn merged with the AEEU to form Amicus in 2002. This resulted in TASS and the former AUEW (by then part of the AEEU) being re-united within one union. Technical, Administrative and Supervisory