## EPA proposes new heavy-duty truck emissions rules

##### 08 March 2022

The US Environmental Protection Agency (EPA) is proposing new, stronger standards to promote clean air and reduce pollution from heavy-duty vehicles and engines starting in model year (MY) 2027.

The proposed multi-pollutant rule would further reduce air pollution from heavy-duty engines and vehicles across the United States, including ozone and particulate matter (PM). In addition, as part of this rulemaking, EPA is proposing targeted updates to the existing Heavy-Duty Greenhouse Gas Emissions Phase 2 program (HD GHG Phase 2). This proposed rulemaking builds on and improves the existing emission control program for on-highway heavy-duty engines and vehicles.

EPA is co-proposing two regulatory options for new NOx standards: proposed Option 1 and proposed Option 2. The proposed rulemaking would change key provisions of the heavy-duty emission control program, including the standards, test procedures, regulatory useful life, emission-related warranty, and other requirements. The two regulatory options (proposed Options 1 and 2) would result in different numeric levels of the standards and lengths of useful life and warranty periods.

The requirements in the proposed Option 1 and the proposed Option 2 would lower emissions of NOx and other air pollutants (PM, hydrocarbons (HC), air toxics, and carbon monoxide (CO)) beginning as early as model year (MY) 2027.

EPA estimates that if finalized as proposed:

• Proposed Option 1 would reduce NOx emissions from heavy-duty vehicles in 2040 by more than 50%; by 2045, a year by which most of the regulated fleet would have turned over, heavy-duty NOx emissions would be more than 60% lower than they would have been without this action.

• Proposed Option 2 would reduce heavy-duty NOx emissions in 2045 by 47%.

• In 2045, the proposed Option 1 would result in total annual monetized ozone- and PM2.5-related benefits of $12 and$33 billion at a 3% discount rate, and $10 and$30 billion at a 7% discount rate.

• In the same calendar year, proposed Option 2 would result in total annual monetized ozone- and PM2.5-related benefits of $9 and$26 billion at a 3% discount rate, and $8 and$23 billion at a 7% discount rate.

Given the analysis we present in this proposal, we currently believe that Option 1 may be a more appropriate level of stringency as it would result in a greater level of achievable emission reduction for the model years proposed.

—“Control of Air Pollution from New Motor Vehicles: Heavy-Duty Engine and Vehicle Standards”

The proposed revisions to existing GHG standards for MY2027 and beyond would set updated GHG emissions standards for subsectors where electrification is advancing at a more rapid pace. These sectors include school buses, transit buses, commercial delivery trucks, and short-haul tractors.

In a separate action, EPA will be setting new GHG emissions standards for heavy-duty vehicles as soon as model year 2030. This action will more comprehensively address the long-term trend towards zero emissions vehicles across the heavy-duty sector.