The Environmental Protection Agency (EPA) is preparing to soon release its updated final rule for Heavy-Duty Engine and Vehicles regarding the regulation of nitrous oxides (NOx) ahead of its impending January implementation.
The 2027 NOx rule was first released in 2022 by the Biden Administration. The rule was set to require heavy-duty commercial vehicles to limit NOx emissions to 0.035 grams per horsepower-hour during normal operation, 0.050 grams at low load, and 10.0 grams at idle, while also increasing the useful life of governed vehicles and dramatically extending emissions warranties.
EPA Administrator Lee Zeldin announced early in his tenure his intent to reconsider the rule, and in November committed to make ‘major changes’ while keeping the 2027 implementation timeline.
According to reporting this week by CCJ (owned by Fusable, parent company of TPS), those changes are expected to:
- Roll back warranty mandates: Rescind the extended warranty requirement, restoring the agency’s previous, less restrictive warranty and useful-life rules. Biden-era regulations required OEMs extend warranties to 450,000 miles from 100,000 and useful life limits to 650,000 miles from 435,000 miles.
- Boost compliance credits: Expand the availability and flexibility of the credit system manufacturers use to meet regulatory averages.
- Extend testing timelines: Grant OEMs more time to validate the reliability of new emissions-control systems under real-world operating conditions.
- Allow temporary penalties: Permit manufacturers to pay non-conformance penalties as a short-term alternative if they cannot immediately meet the hardware standards.
[RELATED: Cummins delays launch of two engines, cites regulatory uncertainty]
The proposal is, however, expected to maintain the NOx reduction levels of the initial rule. CCJ reports the White House office of Management and Budget completed its review of the EPA plan last week.
