EPA Proposes to Loosen Heavy-Duty Truck Emissions Rules

On July 9, 2026 the U.S. Environmental Protection Agency announced a rule change that would scale back two key provisions of the 2023 Biden-era heavy-duty truck emissions rule. The agency seeks to shorten the warranty period for emissions-control systems and to delay the increase in the “useful life” mileage requirement for new engines. It also proposes replacing the mandatory “limp-mode” speed restriction—triggered when emissions controls fail—with a driver alert system.

NPR

The 2023 rule, finalized under President Joe Biden, required diesel engines to meet stricter nitrogen-oxide (NOx) limits and extended the emissions-control warranty from 100,000 miles to 450,000 miles. It also raised the mileage over which standards apply from 435,000 miles to 650,000 miles beginning in model year 2027. The Trump administration has been rolling back several Biden climate and vehicle-emissions policies, including the 2009 Endangerment Finding and federal tailpipe standards for cars and trucks.

The Hill

• Lee Zeldin, EPA Administrator, leads the proposal.

EPA Proposes Easing Heavy-Duty Truck Pollution Rules

• Aaron Szabo, EPA Assistant Administrator for Air and Radiation, defends the changes as cost-saving.

EPA Proposes Easing Heavy-Duty Truck Pollution Rules

• Katherine García, director of the Sierra Club’s Clean Transportation for All campaign, leads environmental opposition.

NPR

• Environmental Defense Fund (EDF) and Peter Zalzal, associate vice president for clean-air strategies at EDF, represent the broader environmental community.

The Hill

• American Trucking Associations (ATA) and Kelly Loeffler, head of the U.S. Small Business Administration, advocate for the revisions on behalf of the trucking industry.

NPR

• EPA estimates industry savings of $12 billion total, or up to $6,000 per new truck.

Fox News (website)

• NPR reports per-engine savings of $4,130–$6,152.

Fox News (website)

• The EPA projects a 4.2 % increase in NOx emissions by 2030 and 11.6 % by 2055 under the proposal.

NPR

• The Hill notes the shorter warranty would reduce the rule’s effectiveness by 12 % in 2055.

The Hill

• EPA maintains that the rule would still achieve nearly 90 % of the NOx reductions originally forecasted.

Reuters

Heavy-duty trucks constitute only about 5 % of U.S. vehicles but are the largest source of pollutants that trigger asthma attacks, bronchitis, heart attacks, strokes and premature deaths. Changes to warranty and “limp-mode” requirements could allow higher-polluting engines to remain on the road longer, potentially worsening respiratory health outcomes and contributing to acid-rain formation.

NPR

• Lee Zeldin said the existing requirements were “unworkable, would drive up costs and result in fewer choices,” adding that the rule “will ease real burdens for operators.”

NPR

• Aaron Szabo argued the revisions would “reduce compliance costs by up to 50 percent” and help keep “engines cheaper and in turn lower the costs of the goods that trucks carry.”

EPA Proposes Easing Heavy-Duty Truck Pollution Rules

• The American Trucking Associations requested that manufacturers be allowed to pay penalties instead of meeting the warranty and useful-life provisions while they develop compliant engines.

NPR

• Katherine García warned that “clean truck standards save lives” and that weakening them would increase “toxic pollution in the air.”

NPR

• The Environmental Defense Fund stated, “This Trump EPA proposal to weaken vital clean air protections will mean more health harms and higher costs.”

The Hill

• Peter Zalzal echoed the health concerns, noting that higher NOx levels exacerbate asthma and increase susceptibility to respiratory infections.

The Hill

Sources differ on the projected impact of the rule: NPR quantifies a 4.2 % NOx rise by 2030, while Reuters emphasizes that “the decline in smog-forming nitrogen oxides still would be nearly 90 % of forecasted reductions.” The Hill estimates a 12 % reduction in rule effectiveness by 2055. No agency modeling of direct air-quality or public-health outcomes was provided.

The Hill

• “If finalized, these changes will help manufacturers keep improving their vehicles without being forced to rush products to market before they're ready,” — Lee Zeldin, EPA Administrator

NPR

• “Clean truck standards save lives,” — Katherine García, Director, Sierra Club Clean Transportation for All

NPR

• “This Trump EPA proposal to weaken vital clean air protections will mean more health harms and higher costs,” — Environmental Defense Fund

Reuters

• “Even if you’ve never driven a truck in your life, when it costs less to move goods, it costs less to buy them. Those savings get passed down to you at the grocery store, the hardware store on nearly everything a truck delivers.” — Lee Zeldin, EPA Administrator

EPA Proposes Easing Heavy-Duty Truck Pollution Rules

• “We're both making the products more reliable and decreasing the impact from DEF. And we're also bringing down the price of the whole supply chain by reducing the cost of these new trucks,” — Aaron Szabo, EPA Assistant Administrator

Fox News (website)

The EPA has opened a public-comment period for the proposal, but no specific timeline for a final rule has been announced. Stakeholders, including environmental groups and industry associations, are expected to submit comments before the agency decides whether to adopt the revisions.

NPR