Emissions Testing in Arizona

Air pollution is a big cause for concern. Motor vehicle CO2 emissions are one of the major causes of air pollution, which is why there are laws on a state-by-state basis that enforce setting emissions standards through vehicle emissions testing. There is greatly increased traffic in the metropolitan areas of Phoenix and Tucson, which is why emissions testing in Arizona was implemented in the early 1990s.

The federal Clean Air Act of 1970 was the first law regulating emissions in vehicles on a national level – it required states with metropolitan areas that did not meet a certain air standard to implement testing. The Clean Air Act was amended in 1990, and it’s from this period that most of our modern emissions tests and testing facilities derive. According to the EPA, “aggregate emissions of six common pollutants dropped 70% between 1970 and 2015.” We are making great progress!

Arizona Department of Environmental Quality (ADEQ) is the agency that manages vehicle emissions, in order to preserve our health and the environment. ADEQ has created the Vehicle Emissions Inspection Program (VEIP), which is a program for vehicle emission testing and repairs.

In Arizona, all vehicles in the Phoenix or Tucson metro areas that were made after 1967, must to undergo an emissions inspection every two years. New vehicles which are powered by alternative fuels do not have to be tested when they are registered for the first time; however, an emissions inspection is compulsory prior to registration in the following years.

What Does Emissions Testing in Arizona Involve?

There are four types of emissions tests – the test that is done on your vehicle depends primarily on the age of the vehicle. The following are the tests done by Arizona to test your vehicle’s emissions to meet federal standards:

IM 147
For vehicles weighing less than 8500lbs GVWR and made between 1981 through 1995, this test simulates urban driving at different speeds while measuring the exhaust.

Steady State Loaded/Idle
This test is used for even older vehicles, starting with 1967 through 1995 in Tucson and through 1980 in Phoenix. This test is also used for some newer vehicles weighing over 8500lbs GVWR. In this test, the vehicle is tested both while idling as well as at roughly 25-30mph.

OBD (On-Board Diagnostics)
This is fast becoming the most commonly administered test as it is quick and easy, and used on all light duty vehicles 1996 and newer. It simply involves connecting directly to the computer of the vehicle and monitoring the engine emission control systems operation. This test especially is great for early recognition of engine problems.

Tests on diesel vehicles check for opacity, or smoke density, using an opacity meter to measure the exhaust.

Preparing for Your Emissions Test

Vehicles that do not pass emissions inspection can be tested again after they are repaired. To best prepare your vehicle for emissions testing in Arizona, you should make sure of the following:

  • Be sure your vehicle is warmed up, but not overheated.
  • Remove any trailers or attachments.
  • Do not have the air conditioning running.
  • Be sure to have at least a half tank of gas.
  • Try to have an oil change done soon beforehand, as well as a basic tune-up.
  • Be sure your check engine light is off – you will fail immediately if it is on!

You should also bring with you the test fee and a key for the gas tank if applicable. If you are taking a re-test, be sure to bring the original inspection report. If this is your first time registering in Arizona, also bring your previous year vehicle registration as well as the title or bill of sale.

You can find testing locations, as well as check for wait times here.

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