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':
What Is Art? "vagueness, mysteriousness, obscurity and inaccessibility to the masses". Tolstoy lambastes such works, insisting that art can and should be comprehensible to everyone. Having emphasised that art has a function in the improvement of humanity - capable of expressing man’s best sentiment - he finds it offensive that artists should be so wilfully and arrogantly abstruse. One criticism Tolstoy levels against art is that at some point it "ceased to be sincere and became artificial and cerebral", leading to the creation of millions of works of technical brilliance but few of honourable sentiment. Tolstoy outlines four common markers of bad art: