The US Environmental Protection Agency (EPA) released a proposed rulemaking for model year 2023-2026 light-duty vehicle greenhouse gas emissions standards, and outlined its plans to initiate a subsequent rulemaking to set standards for MY 2027 and beyond, to speed the transition of the light-duty vehicle fleet toward a zero emissions future. In addition, EPA announced plans to update air pollution standards for heavy-duty vehicles.

The proposal would establish more stringent standards for each model year starting in 2023. The proposed standards drive 10% greater emissions improvement than the SAFE rule standards for MY 2023 vehicles and then 5% greater emissions improvement each year after. This proposal would significantly strengthen current standards, which become only 1.5% more stringent each year. EPA is not proposing to revise GHG emissions standards for MY 2021 and MY 2022.

For Model Year 2026, this results in an EPA-projected fleet-wide CO₂ emissions standard of 171 grams per mile—approximately 52 mpg US, which in turn corresponds to a real-world label value of 38.2 mpg. (The “real-world” value does not incorporate the GHG emissions reduction benefits of improved air conditioning.)

EPA’s benefits analysis determines that:

• The proposed rule would save American drivers between $120 to $250 billion in fuel costs through 2050.

• This proposal would result in 2.2 billion tons of avoided CO₂ emissions through 2050. The cumulative emissions avoided through 2050 are roughly equal to GHG emissions from all petroleum combustion in the US for all of 2019.

• On average, the cost to auto manufacturers to comply would be just over $1,000 per vehicle in MY 2026.

• The proposal would provide between $86 and $140 billion in net benefits through 2050. Benefits result from improved public health, fuel savings, and reduced impacts from climate change such as property damages due to increased flooding and changes to agricultural production.

• Between $3.6 and $8.8 billion of the total benefits through 2050 are attributable to reduced emissions of non-GHG pollutants primarily those that contribute to ambient concentrations of smaller particulate matter (PM_2.5).

EPA projects that during the four-year ramping-up of the stringency of this proposed program, the standards could be met with a combination of internal combustion engine vehicles, hybrid electric vehicles, and gradually increasing sales of electric vehicles (EVs), up to about an 8% market share by MY 2026. Given that EVs represented about 2% of the new vehicle market in MY 2019, this would represent a significant increase in EV market penetration, the EPA said.

As with EPA’s previous light-duty GHG programs, EPA is proposing standards expressed as footprint-based curves for both passenger cars and trucks. Under this approach, each manufacturer has a unique standard for the passenger car and truck categories, for each model year, based on the sales-weighted footprint-based CO₂ targets of the vehicles produced in each MY.

Heavy-Duty Trucks. EPA also announced plans to reduce GHG emissions and other harmful air pollutants from heavy-duty trucks. The agency is working on a series of major rulemakings over the next three years. The first rulemaking, to be finalized in 2022, will apply to heavy duty vehicles starting in MY 2027.

That action will set new standards for criteria pollutants for the entire sector as well as targeted upgrades to the current “Phase 2” GHG emissions standards for that model year. A second rule would set more robust GHG emission standards for new heavy-duty vehicles sold as soon as MY 2030 and beyond.