Key Transportation Terminology

The Energy Policy Act (EPAct) includes specific transportation terminology. These key terms and definitions help state and alternative fuel provider fleets understand their EPAct requirements. Find additional terms and definitions in the statutes and regulations.

Alternative Compliance Vehicle

This term refers to a vehicle—or required alternative fuel vehicle (AFV)—that must be included in calculating a fleet's petroleum reduction requirement under the Alternative Compliance option. Alternative Compliance vehicles are:

  • AFVs acquired in previous model years in compliance with the Standard Compliance requirements (minus retirements)
  • Light-duty vehicles (conventional or AFV) planned to be acquired in the upcoming waiver model year instead of the AFV requirements that otherwise would be met under the Standard Compliance requirements
  • Light-duty vehicles (conventional or AFV) acquired in previous waiver model years instead of the AFV requirements that would otherwise be met under the Standard Compliance requirements (minus retirements)

Alternative Compliance Vehicle Inventory

This term refers to the Alternative Compliance vehicles in a fleet for the upcoming waiver model year. Alternative Compliance vehicles retired from the fleet before the start of the model year are not included in the Alternative Compliance vehicle inventory.

Alternative Fuels

The Energy Policy Act of 1992 defined these fuels as alternative fuels:

  • Methanol, ethanol, and other alcohols
  • Blends of 85% or more of alcohol with gasoline
  • Natural gas and liquid fuels domestically produced from natural gas
  • Liquefied petroleum gas (propane)
  • Coal-derived liquid fuels
  • Hydrogen
  • Electricity
  • Fuels (other than alcohol) derived from biological materials (including pure biodiesel (B100))1
  • P-Series.2
  • 1 In its March 1996 final rule establishing the Alternative Fuel Transportation Program regulations, the U.S. Department of Energy concluded that neat/pure biodiesel (B100) is derived from biological materials and therefore is an "alternative fuel." In January 2001, the Biodiesel Final Rule made it possible for fleets to earn EPAct credits for using biodiesel blends of at least 20%. This rule does not make B20 (a blend containing 20% pure biodiesel and 80% conventional diesel) an alternative fuel but gives one credit for every 450 gallons of pure biodiesel used in biodiesel blends of B20 or higher.
  • 2 In a May 1999 final rule, DOE classified three P-Series fuels as "alternative fuel."

Alternative Fuel Infrastructure

Alternative fuel infrastructure is property used for the storage and dispensing of an alternative fuel into the fuel tank of a motor vehicle propelled by such fuel, or used for recharging motor vehicles or neighborhood electric vehicles propelled by electricity. In plain English, alternative fuel infrastructure is an alternative fueling station, a charging station, or a battery-exchange station.

Alternative Fuel Non-Road Equipment

This term refers to mobile, non-road equipment that operates on alternative fuel, including but not limited to riding lawnmowers, forklifts, tractors, bulldozers, backhoes, front-end loaders, and rollers/compactors.

Alternative Fuel Vehicles

Alternative fuel vehicles (AFVs) include any dedicated or dual fueled vehicle, which is any vehicle that operates solely on, or is capable of operating on, at least one alternative fuel.

Covered Fleets

State and alternative fuel provider fleets are considered covered fleets if they own, operate, lease, or otherwise control 50 or more non-excluded light-duty vehicles (less than or equal to 8,500 pounds) and if at least 20 of those vehicles are used primarily within a single Metropolitan Statistical Area/Consolidated Metropolitan Statistical Area and are centrally fueled or capable of being centrally fueled.

Emerging Technology

This term refers to a pre-production or pre-commercially available version of a fuel cell electric vehicle, hybrid electric vehicle, medium- or heavy-duty electric vehicle, medium- or heavy-duty fuel cell electric vehicle, neighborhood electric vehicle (NEV), or plug-in electric drive vehicle.

Excluded Vehicles

The following vehicles do not count toward a fleet's annual light-duty vehicle count and the associated determination of AFV-acquisition requirements because they are excluded. They do count, however, toward satisfying AFV-acquisition requirements.

  • Emergency vehicles, including vehicles directly used in the emergency repair of transmission lines and in the restoration of electricity service following power outages
  • Law enforcement vehicles
  • Nonroad vehicles
  • Vehicles parked at private residences when not in use
  • Vehicles used for evaluating or testing products of a motor vehicle manufacturer, including those owned or held by a university for research purposes
  • Vehicles owned or held by a testing laboratory or other evaluation facility that are used solely for evaluating the vehicles' performance
  • Vehicles acquired and used for purposes that the U.S. Secretary of Defense certifies must be exempted for national security reasons
  • Vehicles held for lease or rental to the general public
  • Vehicles held for sale by motor vehicle dealers, including demonstration vehicles


The exemption provisions under the Alternative Fuel Transportation Program are specific to the AFV-acquisition requirements of Standard Compliance. Exemptions are based on a lack of available alternative fuels and/or AFVs and are not related to the Alternative Compliance option, under which fleets may adopt multiple strategies for compliance (aside from acquiring AFVs).

Fuel Cell Electric Vehicle

A fuel cell electric vehicle is a motor vehicle or non-road vehicle that uses a fuel cell. A fuel cell is a device that directly converts the chemical energy of a fuel, which is supplied from an external source, and an oxidant into electricity by electrochemical processes occurring at separate electrodes in the device.

Hybrid Electric Vehicle

A hybrid electric vehicle is a new qualified hybrid motor vehicle that draws propulsion energy from onboard sources of stored energy that are both an internal combustion or heat engine using consumable fuel and a rechargeable energy storage system. For more about the definition of a new qualified hybrid motor vehicle, see section 30B(d)(3) of the Internal Revenue Code of 1986 (26 U.S.C. 30B(d)(3)).

Medium-Duty/Heavy-Duty Fuel Cell Electric Vehicle

A medium- or heavy-duty fuel cell electric vehicle is a fuel cell electric vehicle with a gross vehicle weight rating of more than 8,500 pounds.

Medium-Duty/Heavy-Duty Electric Vehicle

These vehicles include electric, hybrid electric, and plug-in hybrid electric vehicles with a gross vehicle weight rating (GVWR) greater than 8,500 pounds. Note that of these vehicles, medium-duty/heavy-duty hybrid electric vehicles are not AFVs if they lack an engine that is capable of operating on a liquid or gaseous alternative fuel.

Model Year

For the purpose of the Alternative Fuel Transportation Program, a model year runs from September 1 through August 31 of the following calendar year. Model year 2024, for example, began on Sept. 1, 2023, and ends on Aug. 31, 2024.

Neighborhood Electric Vehicle

A neighborhood electric vehicle (NEV) is a four-wheeled on-road or non-road vehicle that: (1) has a top attainable speed in one mile of more than 20 mph and not more than 25 mph on a paved, level surface; and (2) is propelled by an electric motor and an on-board, rechargeable energy storage system that is rechargeable using an off-board source of electricity.

Non-AFV Electric Vehicle

Non-AFV electric vehicles include neighborhood electric vehicles and the non-AFV versions of the following light-duty vehicles:

  • Hybrid electric vehicles (HEVs)
  • Plug-in hybrid electric vehicles (PHEVs)
  • Fuel cell electric vehicles (FCEVs)

Plug-In Electric Drive Vehicle

A plug-in electric drive vehicle is a vehicle that:

  • Draws motive power from a battery with a capacity of at least 4 kilowatt hours
  • Can be recharged from an external source of electricity for motive power
  • Is a light-, medium-, or heavy-duty motor vehicle or non-road vehicle (A non-road vehicle is a vehicle that is powered by a non-road engine and that is not a motor vehicle or a vehicle used solely for competition. For more about the definitions of light-, medium-, and heavy-duty vehicles, see section 216 of the Clean Air Act (42 U.S.C. 7550).)
  • In the case of a plug-in hybrid electric vehicle, includes an on-board method of charging the energy storage system and/or providing motive power.

Regulatory Information Line

For help with understanding and meeting Energy Policy Act requirements, state and alternative fuel provider fleets may contact the Regulatory Information Line: