Public Utilities Code § 5402
ARTICLE 5. Basis of Charges
No person, partnership, corporation, or organization shall sell transportation by a passenger stage on an individual-fare basis for a sightseeing trip in California on a route for which a passenger stage corporation has obtained a certificate of convenience and necessity if the seller intends to charter or charters the passenger stage in California at a rate per passenger which is less than the individual fare for which the transportation is sold.