EDF, Allies, Move to Defend California Clean Car and Truck Standards in Court

(January 29, 2025) Environmental Defense Fund and a broad group of allies is taking action to defend California’s protective clean vehicle standards, which provide vital protections for people’s health and the environment.

The groups recently filed motions to intervene with the U.S. Court of Appeals for the Ninth Circuit in two cases: a challenge to EPA’s preemption waivers for the Advanced Clean Cars II (ACCII) Standards; and a challenge to the Heavy-Duty Vehicle Low NO_x Omnibus Standards.

“California’s standards will help protect millions of people from dangerous traffic pollution, while also making it easier for people to buy the clean cars and trucks that will save them money,” said Andy Su, Clean Transportation Attorney for Environmental Defense. “EPA’s preemption waivers for these protective standards are rooted in Congress’s specific instructions in the Clean Air Act and in more than half a century of legal precedent.”

For more than 50 years, the Clean Air Act has included a waiver provision that allows California to adopt emission standards for new vehicles that are more protective than the national standards in order to safeguard people against harmful air pollution. EPA has granted more than 80 waivers in that time, during both Democratic and Republican administrations. Those waivers helped spur most of the key U.S. advances in motor vehicle pollution control – including the first leaded-gasoline phase-out requirements; the first emission standards for hydrocarbons, carbon monoxide, diesel particulates, and greenhouse gases; and technologies including three-way catalytic converters, fuel injection, and zero-emission technologies.

In December 2024, EPA continued that long precedent by approving several waivers for California programs, including the two now being challenged:

• The Advanced Clean Cars II (ACCII) program applies to new cars and passenger trucks starting in model year 2026. It requires gradually increasing sales of zero emission vehicles including plug-in hybrids through 2035 and increases choices for people who want to buy a car that saves them money on fuel and maintenance costs while also delivering cleaner, healthier air. More than two million zero-emitting vehicles have already been sold in California – more than a quarter of all recent sales. Eleven other states – Colorado, Delaware, Maryland, Massachusetts, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, and Washington – and the District of Columbia have also adopted ACCII.
• The Heavy-Duty Low NO_x Omnibus Standards will reduce certain types of tailpipe pollution from new heavy-duty vehicles like freight trucks and buses. The standards will help protect millions of people from NOx, which is a pollutant that causes smog, and particulate matter. Those types of pollution are linked to serious heart and lung diseases and premature deaths, and are especially dangerous for children, older people, people who work outdoors, and people with health conditions like asthma. Nine other states – Colorado, Massachusetts, New Jersey, New Mexico, New York, Oregon, Rhode Island, Vermont, and Washington – have also adopted the Heavy-Duty Low NOx Omnibus Standards.  

The American Free Enterprise Chamber of Commerce is challenging both preemption waivers. 

EDF and the Center for Biological Diversity, Conservation Law Foundation, Natural Resources Defense Council, Public Citizen, and Sierra Club filed a motion to intervene in defense of the preemption waiver for the ACCII standards.

EDF, Natural Resources Defense Council, and Sierra Club also moved to intervene in defense the Heavy-Duty Low NOx Omnibus standards.