Cal. Health & Saf. Code § 43010
With respect to the program designed and adopted by the Department of Consumer Affairs pursuant to Chapter 20.4 (commencing with Section 9889.50) of Division 3 of the Business and Professions Code, the state board shall, in time for the Department of Consumer Affairs to comply with the schedule specified in subdivisions (a) and (b) of Section 9889.55 of that code, after public hearings, prescribe maximum air pollution emission standards to be applied in inspecting motor vehicles.
In prescribing such standards, the state board shall undertake such studies and experiments as are necessary and feasible, evaluate available data, and confer with automotive engineers.
The standards shall be set at a level reasonably achievable for each class and model of motor vehicle when operating in a reasonably sound mechanical condition, allowing for the effects of installed motor vehicle pollution control devices, and the motor vehicle's age and total mileage. The standards shall be designed to secure the operation of all such motor vehicles, as soon as possible, with a substantial reduction in air pollution emissions, and shall be revised from time to time, as experience justifies.
Ca. Health and Saf. Code § 43010