Every owner of a vehicle used in the transportation of passengers for hire, including taxicabs, when the operation of the vehicle is not subject to regulation by the Public Utilities Commission, shall maintain, whenever he or she may be engaged in conducting those operations, proof of financial responsibility resulting from the ownership or operation of the vehicle and arising by reason of personal injury to, or death of, any one person, of at least fifteen thousand dollars ($15,000), and, subject to the limit of fifteen thousand dollars ($15,000) for each person injured or killed, of at least thirty thousand dollars ($30,000) for the injury to, or the death of, two or more persons in any one accident, and for damages to property of at least five thousand dollars ($5,000) resulting from any one accident. Proof of financial responsibility may be maintained by either: