(a)
(1)
The department, in cooperation with the state board, shall prescribe maximum emission standards to be applied in inspecting motor vehicles under this chapter.
(2)
In prescribing the standards, the department shall undertake studies and experiments which are necessary and feasible, evaluate available data, and confer with automotive engineers.
(3)
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.
(4)
The standards shall be designed so that motor vehicles failing the test specified in Section 44012 will be operated, as soon as possible, with a substantial reduction in emissions, and shall be revised from time to time as experience justifies.
(b)
The department, in cooperation with the state board, shall research and prescribe test procedures to be applied in inspecting motor vehicles under this chapter, which procedures shall be simple, cost-effective, and consistent with Section 44012. The department may revise the test procedures from time to time as experience justifies. To the extent that any test procedure revision requires new equipment, or a change in equipment, at licensed smog check stations, the department shall provide a reasonable period of time for the acquisition and installation of that new or changed equipment.
(c)
Notwithstanding any other provision of this chapter, the maximum emission standards and test procedures prescribed in subdivisions (a) and (b) for a motor vehicle class and model-year shall not be more stringent than the emission standards and test procedures under which that motor vehicle’s class and model-year was certified. Emission standards and test procedures prescribed by the department shall ensure that not more than 5 percent of the vehicles or engines, which would otherwise meet the requirements of this part, will fail the inspection and maintenance test for that class of vehicle or engine.