“Existing taxi service” means any public passenger transportation service which (1) is not subject to the jurisdiction, control, and regulation of the Public Utilities Commission, (2) is available for hire on an exclusive or shared-ride basis, (3) is on call or demand over the public streets within the county in a motor vehicle of distinctive color or insignia equipped with a taximeter which is demand activated and operated by a licensed driver at the direction of passengers, and (4) was operating on January 1, 1974.