California Code, Health and Safety Code - HSC § 44254

(a) The state board shall publish the smog index numbers in a form that is convenient for use by the Department of Motor Vehicles, the bureau, vehicle owners, manufacturers, dealers, and consumers shopping for a new or used motor vehicle of a particular type.

(b) The state board, in consultation with the Environmental Protection Agency, shall adopt regulations specifying a form of decal to be affixed by manufacturers to new motor vehicles pursuant to Section 43200.5 to inform purchasers of the smog index for the vehicle, a smog index chart listing vehicle model years and the corresponding smog index for that model year to be affixed by motor vehicles dealers to used motor vehicles pursuant to subdivision (c) of Section 43705, and information to inform purchasers of the significance of the smog index and smog index chart.

(c) The state board, in consultation with the Department of Motor Vehicles, shall specify a form of notice to be provided by the Department of Motor Vehicles to each owner of a motor vehicle registered in this state, informing the owner of the smog index for the vehicle and the significance of the smog index.