(a) Express Preemption:

(1) To the extent that any law or regulation of a State or a political subdivision of a State regulates or prohibits tailpipe carbon dioxide emissions from automobiles, such a law or regulation relates to average fuel economy standards within the meaning of 49 U.S.C. 32919.

(A) Automobile fuel economy is directly and substantially related to automobile tailpipe emissions of carbon dioxide;

(B) Carbon dioxide is the natural by-product of automobile fuel consumption;

(C) The most significant and controlling factor in making the measurements necessary to determine the compliance of automobiles with the fuel economy standards in this part is their rate of tailpipe carbon dioxide emissions;

(D) Almost all technologically feasible reduction of tailpipe emissions of carbon dioxide is achievable through improving fuel economy, thereby reducing both the consumption of fuel and the creation and emission of carbon dioxide;

(E) Accordingly, as a practical matter, regulating fuel economy controls the amount of tailpipe emissions of carbon dioxide, and regulating the tailpipe emissions of carbon dioxide controls fuel economy.

(2) As a law or regulation related to fuel economy standards, any law or regulation of a State or a political subdivision of a State regulating or prohibiting tailpipe carbon dioxide emissions from automobiles is expressly preempted under 49 U.S.C. 32919.

(3) A law or regulation of a State or a political subdivision of a State having the direct or substantial effect of regulating or prohibiting tailpipe carbon dioxide emissions from automobiles or automobile fuel economy is a law or regulation related to fuel economy standards and expressly preempted under 49 U.S.C. 32919.

(b) Implied Preemption:

(1) A law or regulation of a State or a political subdivision of a State regulating tailpipe carbon dioxide emissions from automobiles, particularly a law or regulation that is not attribute-based and does not separately regulate passenger cars and light trucks, conflicts with:

(A) The fuel economy standards in this part;

(B) The judgments made by the agency in establishing those standards; and

(C) The achievement of the objectives of the statute (49 U.S.C. Chapter 329) under which those standards were established, including objectives relating to reducing fuel consumption in a manner and to the extent consistent with manufacturer flexibility, consumer choice, and automobile safety.

(2) Any law or regulation of a State or a political subdivision of a State regulating or prohibiting tailpipe carbon dioxide emissions from automobiles is impliedly preempted under 49 U.S.C. Chapter 329.

(3) A law or regulation of a State or a political subdivision of a State having the direct or substantial effect of regulating or prohibiting tailpipe carbon dioxide emissions from automobiles or automobile fuel economy is impliedly preempted under 49 U.S.C. Chapter 329.

[84 FR 51362, Sept. 27, 2019]