The owner of a commercial motor vehicle that is equipped with an auxiliary power or idle reduction technology unit shall, subject to the conditions described in this section, be granted a weight tolerance exemption from the gross, total axle, total tandem or bridge formula weight limits established by § 14-267a. Such weight tolerance exemption shall authorize the operation of such commercial motor vehicle with additional weight equal to the actual weight of the auxiliary power or idle reduction technology unit, but not exceeding five hundred fifty pounds. Such exemption may be granted by any official or law enforcement officer authorized to enforce the provisions of said § 14-267a. To qualify for a weight tolerance exemption, an owner may be required to produce a written certification of the weight of such unit, and to show, by means of a written certification or physical demonstration, that the unit is fully functional at all times. As used in this section, “auxiliary power or idle reduction technology unit” means an integrated system, other than the vehicle’s engine, that provides heat, air conditioning, engine warming, electric components or power to do the work for which the vehicle is designed.