The EPA pointed to advances in zero-emission truck technology and to California's stricter ZEV...

The EPA pointed to advances in zero-emission truck technology and to California's stricter ZEV standards, both of which have been prompting events like this one from the Harbor Trucking Association to give fleets hands-on look at battery-electric and hydrogen fuel cell trucks.

Photo: Chris Brown

The Environmental Protection Agency on April 12 unveiled its proposed Phase 3 greenhouse gas standards for heavy-duty vehicles, which among other things includes a push for more zero-emission trucks.

The administration made the announcement at the same time it unveiled proposed emissions standards for light- and medium-duty vehicles.

EPA's Heavy-Duty Truck Proposed GHG Standards

“Greenhouse Gas Standards for Heavy-Duty Vehicles - Phase 3” would apply to heavy-duty vocational vehicles (such as delivery trucks, refuse haulers or dump trucks, and public utility trucks, as well as transit, shuttle, and school buses) and tractors (such as day cabs and sleeper cabs on tractor-trailer trucks).

EPA said these standards would complement the criteria pollutant standards for MY 2027 and beyond that EPA finalized last December that severely limit NOx emissions and represent the third phase of EPA’s Clean Trucks Plan.

EPA is proposing stronger CO2 standards for MY 2027 HD vehicles that go beyond the current standards that apply under the HD Phase 2 Greenhouse Gas program. The agency is also proposing an additional set of CO2 standards for heavy-duty vehicles that would begin to apply in MY 2028, with progressively lower standards each model year through 2032.

The EPA said the proposed “Phase 3” greenhouse gas regulations use “performance-based standards that enable manufacturers to achieve compliance efficiently based on the composition of their fleets.”

The proposed rules would update some elements of the agency’s credit-banking program (what it calls the Averaging Banking and Trading program), including eliminating the last model year of the HD GHG Phase 2 advanced technology incentive program for certain types of electric highway heavy-duty vehicles.

EPA is proposing to add warranty requirements for batteries and other components of zero-emission vehicles and to require customer-facing battery state-of-health monitors for plug-in hybrid and battery-electric vehicles.

The rulemaking also proposes additional revisions and clarification to certain highway heavy-duty vehicle provisions and certain test procedures for heavy-duty engines.

EPA Proposes Stricter Greenhouse Gas Standards for Heavy-Duty Trucks
EPA Proposes Stricter Greenhouse Gas Standards for Heavy-Duty Trucks

Faster Adoption of Zero-Emission Vehicles

The agency explained that the development of zero-emissions technologies for heavy-duty trucks have been advancing faster than it anticipated when it wrote the GHG Phase 2 rules in 2016.

EPA’s proposal pointed out that:

  • ZEV models are already in use today for some applications and are expected to expand to many more applications.
  • Costs of ZEV technologies have gone down and are projected to continue to fall.
  • Manufacturers have announced plans to rapidly increase their investments in ZEV technologies over the next decade.

It also pointed to states that are pushing for more zero-emission trucks. California and other states have adopted the Advanced Clean Trucks program that includes a manufacturer requirement for zero-emission truck sales. In addition, 17 states and the District of Columbia have signed a Memorandum of Understanding establishing goals to support widespread electrification of the HD vehicle market.

The administration also noted that the 2021 Infrastructure Investment and Jobs Act (commonly referred to as the “Bipartisan Infrastructure Law” or BIL) and the Inflation Reduction Act of 2022 (“Inflation Reduction Act” or IRA) together include many incentives for the development, production, and sale of ZEVs, electric charging infrastructure, and hydrogen, which are expected to spur significant innovation in the heavy-duty sector.

Impact on the Environment

The proposal is projected to avoid 1.8 billion tons of CO2 through 2055, equivalent to eliminating all greenhouse gas emissions from the entire current U.S. transportation sector for an entire year and deliver additional health benefits by reducing other pollutants from these vehicles.

“Despite the significant emissions reductions achieved by previous rulemakings, GHG emissions from HD vehicles continue to impact public health, welfare, and the environment," said the agency in its proposal. "The transportation sector is the largest U.S. source of GHG emissions, representing 27% of total GHG emissions. Within the transportation sector, heavy-duty vehicles are the second largest contributor to GHG emissions and are responsible for 25% of GHG emissions in the sector.”

However, the NRDC (National Resources Defense Council) said the proposed rules for commercial trucks “fall short of what’s needed….For the millions of Americans forced to breathe dirty air because of tailpipe pollution, these proposed truck standards are a disappointment.” It believes that all new trucks should be required to be zero emissions by 2035.

Light- and Medium-Duty Proposed Standards

On the same day, the EPA proposed standards for light- and medium-duty vehicles. These proposals leverage advances in clean vehicle technology to further reduce climate pollution and smog- and soot-forming emissions, according to the EPA.

For additional insight, the light- and medium-duty proposal was reported in more detail by Work Truck, but here are the highlights:

“Multi-Pollutant Emissions Standards for Model Years 2027 and Later Light-Duty and Medium Duty Vehicles” builds on EPA’s existing emissions standards for passenger cars and light trucks for model years 2023 through 2026.

EPA said its proposal considers a broad suite of available emission control technologies, and the standards are designed to allow manufacturers to meet the performance-based standards however works best for their products. EPA expects the standards to drive widespread use of filters to reduce gasoline particulate matter emissions and spur greater deployment of CO2-reducing technologies for gasoline-powered vehicles. The proposed standards are also projected to accelerate the transition to electric vehicles.

Industry Reaction

American Trucking Associations President and CEO Chris Spear issued a statement, saying, "We share the goal of reducing greenhouse gas emissions and improving fuel efficiency and believe any regulation must be practical, achievable, and based on sound science....the Phase 3 standards must take into account the complex challenges and operating conditions facing motor carriers as we manage the transition to a zero-emission future while simultaneously moving more than 72% of the economy's freight.

"As we review the proposed rule, ATA will remain engaged in the regulatory process to ensure the agency arrives at a regulation that has realistic equipment adoption timelines, is technologically feasible, and will not cause additional inflationary pressures if finalized."

He also said that ATA is "extremely disappointed that EPA has chosen to reopen the Phase 2 regulation, which has been set for years. To make the plans and investments necessary for a successful transtion, our industry needs regulatory certainty....our industry has always found ways to partner with EPA on regulations that are tough but achievable. If EPA wants us to remain a willing participant, their going bak and changing what was already agreed upon is not how to do it."

The Clean Freight Coalition, recently formed by a group of trucking and equipment manufacturer associations, issues a statement from Executive Director Jim Mullen. He pointed out that its members are committed to the transition to zero-emission heavy trucks. However, he noted, "Ensuring a feasible transition to new technologies is our primary goal. An adequate infrastructure, including the power grid and charging stations, and the sourcing of required minerals, are essential to the supply chain as part of the transition to a zero-emission future. Further, regulations must provide the lead time, stability, and certainty that allows for the industry to develop the technology, test in real-world conditions, and minimize downtime and operational disruption."

The Owner-Operator Independent Drivers Association, however, slammed the proposed rules.

“The Biden-Harris EPA is continuing their regulatory blitz on small-business truckers," said OOIDA President Todd Spencer in a statement. "The latest proposal comes on the heels of a hurried NOx emissions rulemaking finalized in December along with a California waiver mandating sales of electric trucks. Today’s announcement is a blatant attempt to force consumers into purchasing electric vehicles while a national charging infrastructure network remains absent for heavy-duty commercial trucks.

Noting that there are concerns about EV costs, mileage range, battery weight and safety, charging time, and availability, Spencer said, "It’s baffling that the EPA is pushing forward with more impractical emissions timelines without first addressing these overwhelming concerns with electric CMVs. The pursuit of this radical environmental agenda in conjunction with an anticipated speed limiter mandate will regulate the safest and most experienced truckers off the road."

How to Comment

Written comments may be submitted to the rulemaking docket via, docket ID No. EPA-HQ-OAR-2022-0985. Comments are due 50 days after publication in the Federal Register.

EPA plans to hold a two-day virtual public hearing the Phase 3 GHG proposal on May 2 and 3, 2023. To register to speak at the virtual hearing or attend the hearing (including those who do not intend to provide testimony) notify EPA by April 26, 2023, preferably by email to

Updated 12:00 p.m. EDT to add ATA comments. Updated 4/13/2023 8:40 EDT to add comments fro OOIDA and Clean Freight Coalition.

About the author
Deborah Lockridge

Deborah Lockridge

Editor and Associate Publisher

Reporting on trucking since 1990, Deborah is known for her award-winning magazine editorials and in-depth features on diverse issues, from the driver shortage to maintenance to rapidly changing technology.

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