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Please note: This summary is provided to help you understand the regulations. Consult the references provided for links to the full text of the regulations.

Transportation Modes » Road » Engine Emissions

Diesel Exhaust Fluid (DEF) Summary Full Text
Diesel Fuel Requirements (Truck) Summary Full Text
Engine Emissions (Truck, Idling) Summary Full Text
Engine Emissions (Nonroad and Auxiliary Equipment) Summary Full Text
Engine Emissions (On-board Diagnostics) Summary Full Text
Engine Emissions (Truck, Tailpipe) Summary Full Text
Engine Tampering Summary Full Text
Greenhouse Gas Emissions Summary Full Text
LNG Tank Venting Summary Full Text
National Clean Diesel Program Summary Exit TERC
SmartWay Summary Exit TERC

Diesel Exhaust Fluids (DEF)
Applies to: Anyone who owns or operates a Diesel powered vehicle that uses a Selective Catalytic Reduction (SCR) system to meet federal engine emissions standards.
Requires: No additional requirements beyond those applying to engine maintenance and rebuilding -- article provides background and best practices information.
See also:
  • Clean Air Act
  • Engine Tampering
  • Diesel Fuel Requirements (Truck)
    Applies to: Applies directly to vehicle and engine manufacturers and the refining industry, who are required to produce cleaner running engines and diesel fuel. Applies indirectly to the transportation sector by affecting the cost and availability of fuel.
    Requires: Heavy-duty engines must meet emissions standards for particulates (soot) and ozone precursors (nitrogen oxides and hydrocarbons). Diesel fuel must meet limits on sulfur content.
    See also:
  • Clean Air Act
  • National Clean Diesel Campaign (exit TERC)
  • Engine Emissions (Truck, Idling)
    Applies to: All trucks operating in or passing through an area where state or local idling ordinances are in force. (There are no federal regulations limiting truck idling. However, more than half of U.S. states and dozens of cities and counties have enacted idling laws or ordinances.)
    Requires: Most frequently, idling laws limit the amount of time, in minutes, that a truck and operate its engine while not moving. Many exemptions apply, which can vary widely among locations and states.
    See also:
  • Engine Emissions (Truck, Tailpipe)
  • Fuel Efficiency
  • Greenhouse Gas Emissions
  • National Clean Diesel Campaign (exit TERC)
  • SmartWay Program (exit TERC)
  • Engine Emissions (Nonroad and Auxiliary Equipment)
    Applies to:

    The standards apply directly to engine and equipment manufacturers, rather than owners and operators. In some cases, owners may be required to register their equipment, and to keep records available for inspection.

    Requires:

    The standards limit the allowable level of emissions from a wide variety of non-vehicle engines sold in the United States. Some types of engines, such as forklift trucks and transport refrigeration units, are used widely in the transportation sector.

    See also:
  • Clean Air Act
  • Greenhouse Gas Emissions
  • Engine Emissions (Truck, Idling)
  • Engine Emissions (Truck, Tailpipe)
  • National Clean Diesel Campaign (exit TERC)
  • Engine Emissions (On-board Diagnostics)
    Applies to: Manufacturers or importers of new heavy-duty vehicles or engines intended for highway use; also applies to anyone who converts heavy-duty vehicles or engines used in highway vehicles to run on alternative fuels
    Requires:

    Manufacturers must install systems that monitor the functioning of the vehicle or engine emission control system, and that alerts the operator if corrective action is needed

    See also:
  • Engine Emissions (Truck, Idling)
  • Engine Emissions (Truck, Tailpipe)
  • National Clean Diesel Campaign (exit TERC)
  • SmartWay Program (exit TERC)
  • Engine Emissions (Truck, Tailpipe)
    Applies to: Emissions standards for new vehicles apply to manufacturers and importers. In many locations, inspection and maintenance regulations, and some operating restrictions, apply to vehicle owners and operators.
    Requires:

    New vehicles must emit levels of several hazardous pollutants below specified thresholds tested over standard driving cycles. Existing vehicles registered or operating in specified locations must be inspected periodically. Some states have instituted roadside monitoring programs to detect and test for smoke opacity. Idling restrictions apply in some locations.

    See also:
  • Alternative Fuels
  • Biodiesel
  • Clean Air Act
  • Diesel Fuel Requirements (Truck)
  • Engine Emissions (Truck, Idling)
  • Greenhouse Gas Emissions
  • National Clean Diesel Campaign (exit TERC)
  • SmartWay Program (exit TERC)
  • Engine Tampering
    Applies to: Anyone who is rebuilding or modifying a heavy-duty highway diesel engine from model year 2004 or later
    Requires:

    The rebuilt engine must continue to meet the same emissions standards as those that applied to the engine when new, and the owner must maintain records of work performed and other specified information for at least two years.

    See also:
  • Clean Air Act
  • Engine Emissions (Truck, Idling)
  • Engine Emissions (Truck, Tailpipe)
  • Fuel Efficiency
  • Greenhouse Gas Emissions
  • National Clean Diesel Campaign (exit TERC)
  • SmartWay Program (exit TERC)
  • Greenhouse Gas Emissions
    Applies to: Applies directly to vehicle and engine manufacturers. Applies indirectly to the transportation sector by affecting the cost and performance of vehicles.
    Requires: Rule requires manufacturers to certify that new Class 7 and 8 combination tractors, and many heavy-duty special purpose vehicles, meet fuel efficiency and greenhouse gas emissions standards.
    See also:
  • Clean Air Act
  • Engine Emissions (Truck, Idling)
  • Engine Emissions (Truck, Tailpipe)
  • Fuel Efficiency
  • SmartWay Program (exit TERC)
  • LNG Tank Venting
    Applies to: All liquefied natural gas (LNG) fuel tanks
    Requires: Both fuel level and internal tank temperature must be known to calculate how long an LNG tank can avoid venting fuel to the atmosphere.
    See also:
  • Alternative Fuels
  • Greenhouse Gas Emissions
  • National Clean Diesel Campaign (exit TERC)
    Applies to: EPA's National Clean Diesel Campaign (NCDC) promotes clean air strategies by working with manufacturers, fleet operators, air quality professionals, environmental and community organizations, and state and local officials to reduce diesel emissions
    Requires: Recent diesel rulemakings have focused on light- and heavy-duty highway vehicles, nonroad diesel equipment, locomotive and marine engines, and large ocean-going vessels
    See also:
  • SmartWay Program (exit TERC)
  • SmartWay Program (exit TERC)
    Applies to:

    Shippers, truck and rail transporters, logistics companies, truck stop operators, and others

    Requires:

    SmartWay is a voluntary program that provides resources to help achieve fuel efficiency improvements and emissions reduction, and identifies products and services that reduce transportation-related emissions

    See also:
  • Greenhouse Gas Emissions
  • National Clean Diesel Campaign (exit TERC)
  • Engine Emissions (Truck, Tailpipe)
  • TERC Home