
In a stunning but logical move, the California Air Resources Board (CARB) on Jan. 13 withdrew its request for a statutory waiver from the U.S. EPA that CARB would have required to implement its game-changing Advanced Clean Fleets (ACF) rule.
With the ACF rule — which California was poised to roll out in stages by truck type – now shelved, Canadian cross-border carriers and U.S.-based carriers won’t soon have to comply with yet another ominous set of emission regulations (which would be stricter than existing U.S. federal rules) just to operate within California.

Instead, they may keep spec’ing and buying trucks powered by current-generation diesel engines and not be driven to switch to electric power by a certain date.
By dropping its waiver request, CARB is bowing to the political reality that Donald Trump’s imminent return to power as president means obtaining an EPA waiver for ACF is literally impossible given his stance against all zero-emission vehicle rules and California’s other clean-air emission standards.
“California has withdrawn its pending waiver and authorization requests that U.S. EPA has not yet acted on,” said CARB chairwoman Liane Randolph in a statement. “While we are disappointed that EPA was unable to act on all the [California waiver] requests in time [before President Biden’s term ended], the withdrawal is an important step given the uncertainty presented by the incoming administration that previously attacked California’s programs to protect public health and the climate and has said will continue to oppose those programs.”
Out of state
CARB approved ACF in 2023 with compliance to begin last year, starting with vehicles that operate only in state. The U.S. EPA waiver was needed to apply the rule to out-of-state trucks that operate in California. CARB called ACF “a first-of-its-kind rule” that will transition fleets toward zero-emission medium- and heavy-duty vehicles.
More specifically, ACF was designed to help the state “fully transition the trucks that travel across the state to zero-emissions technology [electric or hydrogen] by 2045” largely via requiring fleets to phase in zero-emission trucks by application.
For example, last-mile delivery and yard trucks were to transition by 2035; work trucks and day cab tractors to be be zero-emission by 2039, and sleeper cab tractors and specialty vehicles by 2042.
“The California Trucking Association [CTA] has consistently stated the Advanced Clean Fleets Rule was unachievable,” Eric Sauer, CTA chief executive, said in a statement. He pointed out that the trucking will work with both CARB and EPA to further cut truck emissions in “a technologically feasible and cost-effective manner that preserves our state and the nation’s critical supply chain.”
Fork in the road
The Advanced Clean Fleet rule should not be confused with California’s separate Advanced Clean Trucks (ACT) rule of 2020 that consists of a ZEV sales requirement for truck makers and a one-time reporting requirement for large entities and fleets. The waiver for ACT was granted in time by the Biden Administration’s EPA, so this rule is not going away.
This alphabet soup makes some sense as ACT and ACF were “always meant to work together,” per a statement issued by the National Truck Equipment Association (NTEA). “ACT would force OEMs to build ZEVs, and ACF would force fleets to buy them. Each rule needed an EPA waiver as it exceeded federal emissions regulations.”
ACF will likely, if not for dead certain, stay shelved for at least four years until Trump’s new term ends. Whether CARB will dust off its waiver request in 2029 remains to be seen. That will turn on whether another Republican or a Democrat succeeds Trump.
Work ahead
Be aware that ACF being on the back burner doesn’t mean that other efforts to increase the share of electric trucks in California won’t go ahead, including those spearheaded by trucking industry associations and truck makers, including the Clean Freight Coalition.
CARB’s withdrawal of a waiver for ACF “can only be viewed as a major victory for our industry… [as it] represents a significant milestone in our industry’s efforts to curb this unattainable regulation,” David Heller, senior vice-president of safety and government affairs of the Truckload Carriers Association, said in a statement.
He said key questions trucking had on this rule “centered on the achievability, affordability and reliability of the equipment that was required and issues with our nation’s corresponding power grid and electricity generation.
Still, Heller said “our work is just beginning… [trucking] has long advocated for equipment that is environmentally friendly to create a better tomorrow, and our history has demonstrated exactly that. Now is the time to begin engaging with our representatives to lay out a strategy with achievable standards with real-world possibilities that places our industry in the driver’s seat.”
A word on waivers
Under the U.S. Clean Air Act (CAA) of 1970, only California has the option to adopt its own vehicle emissions standards. CAA also lets other states adopt California’s stricter emissions standards if each state’s standards are effectively identical to California’s. And California and other states can only enforce their standards after the U.S. EPA grants California a waiver of the applicable federal standards.
Credit: Source link