Air Quality Division: Vehicle Emissions: Alternative Fuel Vehicles

ADEQ Alternative Fuel VehiclesAlternative fueled vehicles are vehicles that use forms of energy other than conventional gasoline and diesel fuel. A detailed definition is found in Arizona Revised Statutes § 1-215.4 . Pursuant to Arizona Revised Statutes (A.R.S.) § 28-2416, in order to qualify for an alternative fuel special plate, the vehicle must be exclusively powered by one of the alternative fuels identified in Arizona Revised Statutes (A.R.S.) § 1-215.4, and be incapable of operating on any other type of fuel.

All alternative fuel vehicles (except electric, solar and hydrogen powered) used to commute into metro Phoenix (Area A) or metro Tucson (Area B) are required to be emissions tested before they are registered.

New Alternative Fuel Vehicles

New alternative fuel vehicles being registered for the first time (with a manufacturer's statement of origin) are not required to be tested, but emissions testing will be required before registration in subsequent years. Alternative fuel vehicles may be tested at any of the vehicle emissions testing facilities.

For bi-fuel vehicles the test is the same as for a conventionally fueled vehicle of the same class, except that two tailpipe emissions tests will be run. A bi-fuel vehicle will first be tested on the fuel it is operating on at the time it is presented for testing. After the first test, the driver will be asked to switch fuels, and a second test will be run. The second test will begin after 30 seconds of operation on the second fuel. (Please note statutory change in A.R.S. § 28-2416, as listed above.)


An alternative fuel certificate is a document that ADEQ issues for vehicles that have been converted to operate on an alternative fuel and allows the vehicle owner to register the vehicle at reduced tax rate. The lower tax rate, intended to encourage the purchase or modification of vehicles to alternative fuels, is provided for in Arizona Revised Statutes § 28-5805 .

The following vehicles are eligible for an alternative fuel certificate:

  • Vehicles that have been converted to operate on an alternative fuel only (dedicated) and are incapable of operating on any other type of fuel.
  • Original equipment manufactured alternative fueled vehicles do not require an alternative fuel certificate. Just provide Motor Vehicle Division with a copy of the certificate from the manufacturer or dealer indicating that the vehicle is exclusively powered by alternative fuel (dedicated) and is incapable of operating on any other type of fuel.

Click here for more information about Alternative Fuel Certification in Phoenix and Tucson.