California Code, Penal Code - PEN § 654.1

It shall be unlawful for any person, acting individually or as an officer or employee of a corporation, or as a member of a copartnership or as a commission agent or employee of another person, firm or corporation, to sell or offer for sale or, to negotiate, provide or arrange for, or to advertise or hold himself out as one who sells or offers for sale or negotiates, provides or arranges for transportation of a person or persons on an individual fare basis over the public highways of the State of California unless such transportation is to be furnished or provided solely by, and such sale is authorized by, a carrier having a valid and existing certificate of convenience and necessity, or other valid and existing permit from the Public Utilities Commission of the State of California, or from the Interstate Commerce Commission of the United States, authorizing the holder of such certificate or permit to provide such transportation.