Feature, Freight News, Logistics, Road

EPA Proposes Easing Heavy-Duty NOx Rule

[ July 24, 2026   //   Gary Burrows ]

The U.S. Environmental Protection Agency has proposed revising its heavy-duty nitrogen oxide (NOx) emissions standards for model year 2027 trucks, a move the agency says could reduce the cost of new commercial vehicles by as much as US$6,000 each while saving the trucking industry an estimated US$12 billion.

The proposal would modify emissions regulations adopted in 2022 that were scheduled to take effect with 2027 model-year heavy-duty trucks. The American Trucking Associations (ATA), which has argued the original rule relied on costly technologies that had not been sufficiently proven under real-world operating conditions, welcomed the proposed changes.

ATA President and CEO Chris Spear joined EPA Administrator Lee Zeldin at an announcement on the National Mall in Washington, D.C., where the agency outlined revisions that incorporate several recommendations previously submitted by the trucking industry.

“ATA has been clear from day one: new environmental standards must be achievable, affordable, and reliable,” Spear said in a statement. “If a truck cannot perform safely and efficiently on America’s highways, then the freight does not move, shelves do not get stocked, and our economy pays the price.”

Among the most significant proposed changes is maintaining the current five-year, 100,000-mile emissions warranty rather than implementing the longer warranty requirements contained in the existing rule. EPA also proposes delaying expanded useful-life requirements for heavy-duty engines until 2030, giving manufacturers additional time to demonstrate durability under real-world operating conditions.

The proposal would also expand compliance flexibility for engine manufacturers by modifying production allowances, broadening the use of emissions credits and establishing nonconformance penalties that would allow manufacturers to continue selling engines that temporarily fall short of the new NOx standard while paying a regulatory penalty.

For fleet operators, one of the most notable operational changes would eliminate automatic speed and power reductions triggered by certain diesel exhaust fluid (DEF) system faults. Instead, EPA proposes replacing those inducements with visible and audible dashboard warnings, responding to concerns that engine derates have contributed to roadside breakdowns, missed deliveries and safety risks.

According to ATA, heavy-duty truck emissions have declined by 99 percent since 1970. The association argued the 2022 rule required an additional 80 percent reduction in NOx emissions over a five-year period, creating significant cost and reliability concerns for fleets and equipment manufacturers.

EPA has opened the proposal for public comment through Aug. 29. A public hearing is scheduled for July 29 before the agency considers issuing a final rule.

For trucking fleets, equipment manufacturers and freight shippers, the outcome of the rulemaking will help determine the cost, availability and operational requirements of the next generation of heavy-duty trucks beginning with the 2027 model year.

What’s Changing Under EPA’s Proposal

Current Rule	Proposed Change
Extended warranty	Keep current warranty
Longer useful life	Delay to 2030
Production limits	More flexibility
DEF derates	Dashboard warnings
NOx credits	Expanded use
No NCP safety valve	Add nonconformance penalties

Tags: American Trucking Associations, U.S. Enviromental Protection Agency