(a) As used in this subchapter, “emergency vehicle” means a motor vehicle designed to be used under emergency conditions to:
(1) Transport personnel and equipment; and
(2) Support the suppression of fires and mitigation of other hazardous situations.
(b) The provisions of this subchapter governing size, weight, and load shall not apply to emergency vehicles, road machinery, or to implements of husbandry, including farm tractors, temporarily moved upon a highway, or to a vehicle operated under the terms of a special permit issued as provided in this chapter.