No person shall use any vehicle, other than a taxicab duly licensed under and operating in accordance with the provisions of this chapter, for transporting the public generally, as passengers for hire, reward, gift, donation or other consideration. In the case of a violation of this section, the violator shall not thereafter be granted a license for a vehicle concerned for a period of three months for the first violation and one year for a subsequent violation. However, this section shall not apply to motor buses or omnibuses operating under proper authority.