1.  A vehicle acquired for use as a taxicab by a certificate holder may only be used in operation as a taxicab for 120 months after the date on which the vehicle was manufactured.

2.  If a vehicle acquired for use as a taxicab by a certificate holder has been in operation as a taxicab for 120 months after the date on which the vehicle was manufactured, the certificate holder:

(a) Shall remove the vehicle from operation as a taxicab; and

(b) Shall not permit the vehicle to be used as a taxicab in the operations of the certificate holder at any time thereafter.