(a) It shall be unlawful for the owner or other person having possession or control of any taxicab, to operate it upon the streets unless the vehicle has an unexpired seal of inspection indicating that it has been duly inspected and found safe and roadworthy within the preceding six months.
(b) If any such taxicab is damaged by reason of a collision, or from any other cause, it shall be unlawful for the owner or other person having possession or control thereof to operate it upon the streets unless the vehicle has been tested and approved at an authorized inspection station within twenty-four hours after such vehicle has been returned to service.
(c) A violation of this section shall constitute grounds for revocation of a taxicab license.