California Code, Health and Safety Code - HSC § 43200.5

(a) The sale and registration in this state of any new motor vehicle is prohibited unless a decal in the form specified by the state board pursuant to subdivision (b) of Section 44254 has been securely affixed by the manufacturer to a window of the motor vehicle, and affixed in accordance with Section 43200 and any regulations adopted pursuant to Section 43200, which discloses the smog index for the vehicle.

(b) This section does not apply to any authorized emergency vehicle, as defined in Section 165 of the Vehicle Code, or to any employer-provided carpool or vanpool vehicle.

(c) This section shall become inoperative five years from the date determined pursuant to Section 32 of the act adding this section, and on the January 1 following that date is repealed.