Tier 4 Criteria Pollutant Standards, Part 1: Phase-In Schedule for Light-Duty and Medium-Duty Vehicles

Ford Motor Company supports the EPA's proposed revisions to the Tier 4 criteria pollutant standards, specifically endorsing the addition of NMOG+NOx bins and the continued use of a Tier 3 Averaging, Banking, and Trading fleet. The company also advocates for regulatory flexibility regarding California OBD requirements and highlights technical challenges related to gasoline particulate filter back pressure.

The Alliance for Automotive Innovation supports the EPA's proposal to extend the Tier 3 emissions program and delay the implementation of Tier 4 standards. They argue that the current EV market growth is slower than anticipated and that manufacturers need more lead time to develop the necessary technologies to meet the more stringent Tier 4 requirements.

The Alliance for Automotive Innovation supports the EPA's proposal to extend the Tier 3 emissions program and delay the implementation of Tier 4 standards. They argue that the current EV market growth is slower than anticipated and that manufacturers need more lead time to develop the necessary technologies to meet the more stringent Tier 4 requirements.

CZV, Inc. (Czinger Vehicles), a small volume manufacturer of hypercars, supports the EPA's proposal to delay the Tier 4 criteria pollutant standards. The company argues that the delay provides necessary development time for small manufacturers and notes that their low-volume production has a negligible impact on air quality.

The Southern Environmental Law Center (SELC) opposes the EPA's proposal to delay the phase-in schedule for Tier 4 criteria pollutant standards for light- and medium-duty vehicles. They argue that the delay is unnecessary because manufacturers have sufficient compliance pathways, and that the amendment will create regulatory uncertainty, harm public health, and increase climate-related damages.

Porsche Cars North America supports the EPA's proposal to delay the Tier 4 criteria pollutant standards by three years to allow for a reassessment of technical and market assumptions. The company argues that the current timeline is impractical due to slower-than-expected electric vehicle adoption and requests specific adjustments to testing procedures, vehicle classifications, and fuel specifications.

Hyundai Motor America supports the proposed 2-year delay of Tier 4 standards and the extension of Tier 3 standards for model years 2027-2028. The company emphasizes the need for regulatory certainty and an expeditious release of Part 2 to facilitate product planning and maintain competitiveness.

Volkswagen Group of America supports the EPA's proposed two-year delay of the Tier 4 program but requests an extension to a three-year delay to ensure the standards are achievable and sustainable. The company also advocates for specific regulatory adjustments, including "deemed compliance" provisions, streamlined OBD certification, and more realistic projections for battery electric vehicle sales.

North American Subaru, Inc. supports the EPA's proposal to delay the Tier 4 criteria pollutant standards, noting that current market realities for electric vehicles do not align with the original rapid deployment expectations. The company specifically requests that the delay be extended to three years to include the 2029 model year to provide manufacturers with a more stable and reasonable regulatory pathway.

Kia Corporation supports the EPA's proposal to extend Tier 3 standards for model years 2027 and 2028 to provide manufacturers with more lead time and market stability. The company also supports the proposal to issue a separate rulemaking for Tier 4 amendments starting in 2029 to ensure technological feasibility and consumer affordability.