The operation of vehicles and equipment used by the Town of Cortlandt Highway Department in the performance of official duties shall be exempt from the requirements of this chapter. Except as otherwise provided in § 197-6 of this chapter, refuse collecting equipment duly licensed by the Town of Cortlandt shall also be exempt from the requirements of this chapter. Gasoline and fuel delivery trucks are also exempt from the requirements of this chapter except as provided in § 197-6 of this chapter.