After September 1, 1991, it shall be unlawful for any person to perform the work or offer, by advertisement or otherwise, to perform the work of an alternative fuels equipment technician until such person has qualified and is certified as an alternative fuels equipment technician. Beginning September 1, 1995, it shall be unlawful for any person to perform work or offer, by advertisement or otherwise, to perform the work of an alternative fuels compression technician until such person has qualified and is certified as an alternative fuels compression technician. Beginning November 1, 1998, it shall be unlawful for any person to perform the work or offer, by advertisement or otherwise, to perform the work of an electric vehicle technician until such person has qualified and is certified as an electric vehicle technician. Electric vehicles that have a manufacturer's warranty shall be serviced by an authorized new car dealer. Any vehicle manufacturer's training center located in the state, which offers alternative fuel and electric vehicle courses meeting new car manufacturing requirements, shall be exempted from this act. Provided, nothing in the Alternative Fuels Technician Certification Act¹ shall be construed to prohibit a noncertified person from converting the engine of a farm tractor, as defined in Section 1-118 of Title 47 of the Oklahoma Statutes, to an engine fueled by alternative fuels, as long as such farm tractor is not operated on the roads and highways of this state.