Flex-fuel Vehicles

Flex-fuel vehicles (FFV) have a single fuel tank, fuel system, and engine. The vehicles are designed to run on regular unleaded gasoline and an alcohol fuel (either ethanol or methanol) in any mixture - for example, 100% gasoline, E85 (85% ethanol, 15% gasoline), or M85 (85% methanol, 15% gasoline) or any combination of these fuels.

Bi-fuel Vehicles

A bi-fuel vehicle has two separate fuel systems, with the capability to easily switch from one to the other. The vehicle can be powered by either system. One fuel system is usually designed to run on gasoline or diesel, in order to assure a readily available fuel source. In currently available U.S. models, the other fuel system is usually designed to run on compressed natural gas (CNG) or liquefied propane gas (LPG).

Compressed Natural Gas (CNG)

Gasoline powered vehicles can be modified to use compressed natural gas. Vehicles can be designed for the dedicated use of CNG, or more commonly as bi-fuel vehicles which can use either CNG or gasoline.

Liquefied Petroleum Gas (LPG)
Gasoline-powered vehicles can be modified to use LPG (more commonly known as propane). LPG has been used to provide energy for transportation for over 60 years, and LPG vehicles are the most common alternative fuel vehicles. Vehicles can be designed for the dedicated use of propane or as bi-fuel vehicles that can use either propane or gasoline.

Electric Vehicles (EVs)

The only vehicles to meet California's Zero Emission Vehicle requirement, battery electric vehicles offer quiet, pollution-free operation. Unfortunately, electricity generation is not pollution free so EVs produce indirect environmental impacts, but are still far cleaner than gasoline-powered vehicles. Though still range limited, recent advances in battery and electric motor technologies have made EVs more practical than ever before.