(Ward DeWitt/Getty Images)
key takeaways:
- EPA is expected to release a draft NOx emissions proposal after OMB completes its review before the Independence Day holiday.
- ATA expects to add flexibility to the proposal, including changes to warranty requirements and compliance credit availability.
- Carriers are delaying truck purchases despite compliant engines available due to uncertainty over regulatory details.
According to the American Trucking Associations, the Environmental Protection Agency is expected to release a draft of its long-awaited notice of proposed rulemaking (NPRM) on changes to nitrogen oxide tailpipe emissions this week.
The Office of Management and Budget completed its review of EPA’s proposal to extend flexibility to truck makers before the Independence Day holiday, ATA chief advocacy and public affairs officer Henry Hanscom told members of the trade group in a July 6 letter.
An NPRM is a formal document issued by a federal agency announcing its intention to change, add, or remove regulations. It outlines the proposal and invites public comment. OMB reviews agency regulations and manages the federal budget.
The EPA is set to implement a Biden-era requirement that NOx emissions for heavy-duty trucks be reduced from 200 mg/hp-hour to 35 mg/hp-hour.
But the trucking industry is still waiting for clarity on key details – including warranty requirements – that typically would have been released much earlier when the rules were being implemented.
ATA expects EPA to rescind an extended warranty mandate and reinstate EPA’s previous warranty and useful-life requirements; Expand the availability and flexibility of compliance credits; and allow temporary use of non-conformity penalties for manufacturers.
EPA did not respond to a request for comment on when the NPRM will be released.
Some truck makers told carriers at the 2026 Advanced Clean Transportation Expo in May that the potential price increase could be halved if five-year, 100,000-mile warranty terms for engine emissions systems remain unchanged.
Those potential price increases have seen carriers take a wait-and-see approach to tractor purchases, even if truck makers have already prepared their EPA 2027-compliant engines.
David Hillman, vice president of integrated technology sales for International Motors, told ACT attendees: “Not a week goes by that I and my team aren’t asked ‘What’s the price?’ …We don’t know the price till date. But if you want to ask, I don’t mind.
“What we don’t want to do is set a price by looking at the rules on the books right now, and then an NPRM comes out that changes that dramatically and then everyone has to reshuffle.”
Traton Division International unveiled plans for an EPA 2027-compliant S13 engine in January. The S13 integrated powertrain was initially slated to be launched in August 2022.
Hanscom said in the letter that ATA supports emissions reductions and believes these flexibilities – combined with a continued commitment to using diesel exhaust fluids – will allow trucking to build on decades of environmental progress.
EPA Administrator Lee Zeldin announced in March 2025 that the 2022 heavy-duty nitrogen oxide (NOx) rule would be reevaluated.
