California Code, Health and Safety Code - HSC § 43658

(a) If the evidence submitted at a public hearing indicates that, in order to preserve the ambient air quality of a district, it is necessary that every 1955 through 1965 model year motor vehicle within the district be equipped with device or devices certified by the state board to control emission of pollutants from the crankcase or exhaust, the district board may adopt rules and regulations to require the installation of such devices.

(b) The rules and regulations shall provide for a schedule of installation by which the motor vehicles are to be equipped with certified device, taking into consideration the number of motor vehicles to be equipped, the availability of such devices, and the availability of licensed installers to install such devices.

(c) The district board shall coordinate its activities pursuant to this section with the Department of the California Highway Patrol and the Department of Motor Vehicles in order to insure adoption of procedures which will facilitate enforcement of the rules and regulations adopted pursuant to this section.