Upon satisfactory fulfillment of the requirements of these regulations, there shall be issued to the applicant a taxicab driver's license in such form as the Public Service Commission may direct and which shall at all times be in the driver's possession when operating a taxicab. A licensee who defaces, removes, or obliterates any official entry made upon the taxicab driver's license shall be punished by the suspension or revocation of the license. Taxicab driver's licenses shall be valid for not less than 1 year and not more than 3 years, as determined by the Public Service Commission. There shall be delivered to each licensed taxicab driver an identification license of such form and style as the Public Service Commission may prescribe, with the taxicab cab driver's license number on it. The license shall be constantly and conspicuously displayed when engaged in operating a taxicab.