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EPA Gives California OK on Strict Truck Zero-Emission Rule

California is now free to require, by some projections, that more than half of all heavy-duty trucks to be sold in the state be powered by all-electric drive by 2035.

David Cullen
David Cullen[Former] Business/Washington Contributing Editor
Read David's Posts
March 31, 2023
EPA Gives California OK on Strict Truck Zero-Emission Rule

California is now free to require, by some projections, that more than half of all heavy-duty trucks to be sold in the state be powered by all-electric drive by 2035.

Photo: Cellcentric

5 min to read


As expected, on March 31 the Environmental Protection Agency granted two requests for “waivers of preemption” that will enable the California Air Resources Board to drastically tighten its heavy-duty vehicle and engine emission standards well beyond those of the federal government.

The gargantuan impact of this EPA action is California is now free to require-- by some projections-- that more than half of all heavy-duty trucks to be sold in the state — including everything from highway tractors to refuse trucks — be powered by all-electric drive by 2035.

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This bellwhether change will be driven by the state’s landmark Advanced Clean Trucks rule. Its regulations are, according to CARB, “part of a holistic approach to accelerate a large-scale transition of zero-emission medium-and heavy-duty vehicles from Class 2b to Class 8."

And thanks to a provision of the federal Clean Air Act dating back to 1967, six other states have instituted truck-emission rules modeled after California’s tougher standards and have been waiting for approval of the waivers requests before enforcing their new rules. Per EPA, other states can only adopt standards that are identical to California’s.

Zero Emissions

The Advanced Clean Trucks rule has two components: a manufacturer sales requirement and a reporting requirement:

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  • Zero-emission truck sales. Manufacturers who certify Class 2b-8 chassis or complete vehicles with combustion engines would be required to sell zero-emission trucks as an increasing percentage of their annual California sales from 2024 to 2035. By 2035, zero-emission truck/chassis sales would need to be 55% of Class 2b – 3 truck sales, 75% of Class 4 – 8 straight truck sales, and 40% of truck tractor sales.

  • Company and fleet reporting. Large employers, including retailers, manufacturers, brokers and others,. are required to report information about shipments and shuttle services. Fleet owners with 50 or more trucks are required to report about their existing fleet operations. "This information will help identify future strategies to ensure that fleets purchase available zero-emission trucks and place them in service where suitable to meet their needs." according to CARB.

The simple (but hugely expensive and massively disruptive) question all this raises is whether or not truck and engine makers will find it technologically and practically possible to comply with such rules in a mere 12 years.

EPA stated that the two waivers were granted after the agency reviewed the “technical information provided by CARB, reviewing comments submitted by the public, and applying the limited authority for review” under the Clean Air Act. In other words, there was very little the agency could have done to not approve these requests. As EPA put it, “Congress intentionally structured this waiver provision to restrict and limit EPA’s ability to deny a waiver.”

There is yet a third CARB waiver request in the wind, pertaining to truck tailpipe pollution standards, that EPA is expected to approve at some point.

EPA California Waiver Specifics

The two approved waivers pertain to these California programs:

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  1. 2018 Heavy-Duty 2018 warranty amendments, which "extend the emissions warranty periods for 2022 and subsequent model year on-road heavy-duty diesel engines and for 2022 and subsequent model year diesel vehicles with a gross vehicle weight rating exceeding 14,000 pounds powered by such engines."

  2. Advanced Clean Trucks regulation, which “requires that manufacturers, produce, and sell increasing quantities of medium- and heavy-duty zero-emission vehicles (ZEVs) and near zero emission vehicles (NZEVs) in California.” The second waiver request also covers these CARB regulations:

  • Zero Emission Powertrain (ZEP) certification regulation, which “establishes certification requirements and optional emission standards for 2021 and subsequent model year medium- and heavy-duty ZEVs and the zero-emission powertrains installed in such vehicles.”

  • Zero Emission Airport Shuttle Bus (ZEAS), which “establishes steadily increasing zero-emission airport shuttle fleet composition requirements.”

This is separate from the Advanced Clean Fleets rule currently making its way through the final regulatory process in California. That proposed regulation would require certain fleets to deploy zero-emissions vehicles starting in 2024 and would establish a clear end date for new medium- and heavy-duty internal combustion engine vehicle sales.

ATA: 'EPA is Sowing the Ground for a Future Supply Chain Crisis'

Just as the granting of the waivers was expected, so was negative reaction to them by trucking stakeholders. In the eyes of the American Trucking Associations, EPA “erred by allowing California to create regulatory patchwork.”

In a statement, ATA President and CEO Chris Spear said that “by granting California’s waiver for its so-called ‘advanced clean trucks’ rule, the EPA is handing over the keys as a national regulator. This isn’t the United States of California, and in order to mollify a never-satisfied fringe environmental lobby by allowing the state to proceed with these technologically infeasible rules on unworkable and unrealistic timelines, the EPA is sowing the ground for a future supply chain crisis.”

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On the other hand, Spear pledged that ATA “will continue to work tirelessly with the EPA on aggressive, achievable timelines for reducing emissions. Over the past 35 years, that collaboration has produced a 98% reduction in truck emissions.”

Spear added that the association “continues to be committed to the path to zero, and we hope EPA will, as it becomes clear that California’s rhetoric is not being matched by technology, reverse course and create a single, achievable national standard.”

Green Takes

Of course, not every organization sees things the way trucking does. Britt Carmon, National Resource Defense Council’s federal clean vehicles advocate, said in a statement that by granting these waivers, "EPA is upholding the authority of California and other states to protect their residents from harmful pollution. Communities across the country are struggling with dangerous air, and manufacturers have the technology to produce non-polluting trucks.

“These rules ensure those clean trucks get on the road and operate long into the future,” she continued. “With the industry announcing new investments in electric vehicles every day, strong standards will guarantee that these promises become reality.”  

Similarly, Dave Cooke, senior vehicles analyst, Clean Transportation Program, for the Union of Concerned Scientists, stated, “We know the damage that pollution from the freight sector is causing, and we know that the trucking industry can put new technologies in place that will reduce that pollution.

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“Now that EPA has issued the waivers, California and the six other states [Massachusetts, New Jersey, New York, Oregon, Vermont, and Washington] that adopted California’s Advanced Clean Truck rule can start implementing it,” he continued. “State leadership on heavy-duty truck rules will ensure that the freight industry reins in its pollution and accelerates the transition to a zero-emission future. We need EPA to approve the remaining waiver for cleaner trucks as quickly as possible.”

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