California Code, Health and Safety Code - HSC § 43655

(a) The state board shall adopt, by regulation, schedules of installation of certified devices to control exhaust emissions for purposes of Section 43652, after consultation with the Department of the California Highway Patrol, the Department of Motor Vehicles, and the bureau.

(b) In establishing the schedules, the state board shall consider all relevant factors, including, but not limited to, the burden of enforcement on the Department of the California Highway Patrol, the Department of Motor Vehicles, and the bureau, the need for rapid installation of motor vehicle pollution control devices in order to preserve and protect the public health, and the existing ambient air quality in the air basins.