EPA Proposes Tougher NOx Limits for Heavy-Duty Trucks Starting With Model Year 2027
In March 2022, EPA proposed the first step of its Clean Trucks Plan, a stricter nitrogen oxide standard for new heavy-duty engines.
On March 7, 2022, the US Environmental Protection Agency proposed stricter limits on nitrogen oxide (NOx) emissions from new heavy-duty diesel and gasoline engines, beginning with model year 2027. EPA described the proposal as the first step in its Clean Trucks Plan. The proposed rule was published in the Federal Register on March 28, 2022.
According to Transport Topics, EPA said the proposal could cut NOx emissions from trucks by as much as 60% by 2045. The federal NOx standard then in force, 0.2 gram per brake horsepower-hour, dated from 2010.
Two options on the table
EPA put forward two options. As summarized by the consulting firm Gladstein, Neandross & Associates and reported by Transport Topics:
- Option 1: about 0.035 gram per brake horsepower-hour for model years 2027 through 2030, tightening to 0.02 gram starting in 2031
- Option 2: 0.05 gram per brake horsepower-hour starting in model year 2027
EPA also proposed updating greenhouse gas standards for segments where electrification was moving faster, including short-haul tractors, delivery trucks, school buses and transit buses. The agency said it planned separate, broader greenhouse gas standards for heavy-duty vehicles as soon as model year 2030.
Industry reaction
American Trucking Associations said it shared EPA's clean-air goal and wanted a single national NOx standard that could be met with workable, reliable technology. The Truck and Engine Manufacturers Association also welcomed the prospect of a national standard and said it hoped the final rule would encourage turnover of older trucks.
Erik Neandross, CEO of Gladstein, Neandross, said either option would lead to "more expensive and more complicated diesel trucks, with lower fuel economy." Allen Schaeffer of the Diesel Technology Forum warned that a rule causing a pre-buy and low-buy cycle in the new truck market would be "bad for jobs, the economy and the environment."
The Union of Concerned Scientists urged EPA to make its rule at least as protective as California's existing low-NOx truck rule.
What it means for drivers and fleets
The proposal did not affect trucks already on the road. It targeted the engines that would go into new trucks starting in model year 2027.
For fleets, the main questions were price, reliability and fuel economy of those future engines, and whether to adjust buying plans ahead of the change. Equipment managers had reason to follow the rulemaking closely, because the choice between the two options would shape how demanding the new technology had to be.
The proposal was open for public comment, giving carriers, owner-operators and manufacturers a chance to weigh in before EPA decided on a final rule.