Comment submitted by Trevar Kolodny and Sarah Wagoner

Summary: The Heritage Foundation supports the EPA's proposal to delay the Tier 4 criteria pollutant standards for light-duty and medium-duty vehicles due to market realities and technological infeasibility. They argue that the EPA should go further by extending the delay through model year 2029, removing certain On Board Diagnostic requirements, and updating economic analyses to reflect rising material costs and performance losses.