No chauffeur may operate a taxicab, river taxi, limousine or bus in excess of twelve (12) consecutive hours. No chauffeur may engage in total gainful employment, whether chauffeuring or otherwise, for more than sixteen (16) hours in any twenty-four- (24-) hour period if the chauffeur has actually performed any chauffeuring in that twenty-four- (24-) hour period. [Ord. 01-02 § 3.]