Regulations for Emissions from Vehicles and Engines

  • EPA Regulations

    Find information about Light- and Medium-duty Vehicles and Heavy-Duty Vehicles.

  • Onroad

    Vehicles on road
    • Regulations for onroad vehicles and engines.
    See onroad rules

  • Nonroad

    sea and mountain
    • Regulations for nonroad vehicles and engines.
    See nonroad rules

  • Greenhouse Gas

    Climate change, carbon dioxide

    Regulations for:

    • Light-duty passenger cars & trucks
    • Commercial trucks & buses
    • Aircraft
    • Federal fleets (EISA 141)
    See greenhouse gas rules

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Last updated on September 30, 2025