Alternative Fuel Vehicle Program

Bi-fuel Vehicles

  • Bi-fuel vehicles have two tanks for two separate fuels.
  • Gasoline is commonly paired with CNG or propane.
  • A switch is used to choose between the two fuels.

Dual-fuel Vehicles

  • Dual-fuel vehicles have two tanks for two separate fuels.
  • Both fuels are used at the same time in the combustion chamber to produce power.
  • This system is typically used in diesel engines where the diesel fuel is used as a pilot to ignite the other fuel.

Dedicated-fuel Vehicles

  • Dedicated AFVs use one alternative fuel full-time
  • Currently available are vehicles designed to run on propane
  • electricity
  • compressed or liquefied natural gas
  • battery-electric power
  • Generally, dedicated vehicles provide superior emissions and performance results because their design has been optimized for operations on only one fuel.


  • Operates with a common fuel tank designed to run on varying blends of unleaded gasoline with ethanol.
  • The fuel mixture can contain any mixture ratio up to 85% ethanol known as E85.


  • Operates on two or more energy sources, one of which is electricity.
  • HEVs may combine the engine and fuel system of a conventional vehicle with the batteries and electric motor of an electric vehicle in a single drivetrain.
  • Hybrid vehicles are typically 25-30% more fuel efficient than standard gasoline vehicles.
  • Hybrid vehicles produce fewer emissions due to the greater fuel efficiency.
  • Hybrid vehicles do not count toward EPAct requirements
  • The are considered AFVs under the Governor's EO - 111.
  • The state fleet currently has over 50 light-duty hybrid vehicles.


  • Diesel vehicles are not considered alternative fuel vehicles.
  • Do provide higher fuel economy than comparable gasoline versions.
  • Diesel vehicles operate on a compression ignition cycle which is inherently more fuel efficient than a standard gasoline engine.
  • The compression ignition engine is typically 30-40% more fuel efficient than spark fired gasoline engine.
  • Produces more emissions on a gallon of fuel basis than gasoline.
  • The majority of the state's heavy-duty fleet utilize diesel engines.
Last Updated: 07/01/2014