By Evan Reid, Founder of Haul Handbook · Updated Sep 28, 2026
Arizona tests diesel trucks for smoke only where the truck is registered in one of the two emissions areas, metro Phoenix (Area A) and Tucson (Area B). A.R.S. 49-542 requires a diesel vehicle registering in Area A to pass an annual emissions test, and the state will not register a vehicle until it passes or holds a certificate of waiver. In Area A a diesel over 8,500 pounds GVWR takes the SAE J1667 snap-acceleration opacity test; in Tucson the heaviest diesels take a loaded opacity test. Apportioned (IRP) vehicles are exempt, so the program reaches Arizona-registered trucks in the two metro areas, not interstate fleets on apportioned plates.
The program at a glance
- Program
- Arizona Vehicle Emissions Inspection Program (myAZcar), heavy diesel smoke opacity testing in metro Phoenix (Area A) and Tucson (Area B)
- Agency
- Arizona Department of Environmental Quality (ADEQ), which runs the emissions inspection program under A.R.S. 49-542 and the myAZcar.com test stations; the Arizona Department of Transportation, Motor Vehicle Division, withholds registration until a required test is passed
- Covered vehicles
- Diesel vehicles registered in Area A (metro Phoenix) or Area B (Tucson), plus vehicles registered outside those areas but used to commute to the driver's principal place of employment inside them (A.R.S. 49-542(A)). In Area A the SAE J1667 test applies to a diesel with a GVWR over 8,500 pounds; in Area B the loaded opacity test described below applies to a diesel over 26,000 pounds GVWR or with tandem axles, and lighter trucks get a dynamometer or brake-lugging test by weight class. Arizona apportioned (IRP) registered vehicles are exempt from Arizona emission testing (ADOT Motor Carrier Services FAQ; 49-542(J)(2)(c) lets the director exempt vehicles registered under the international proportional registration article). A.R.S. 49-542 also bars a diesel over 26,000 pounds gross weight that pays gross weight fees in Area A from operating there unless it was built in model year 1988 or later or its engine meets the 40 CFR 86 standards.
- Legal basis
- A.R.S. 49-542 creates the annual or biennial emissions inspection program for vehicles registered in Area A and Area B, requires a diesel registering in Area A to take and pass an annual test (a J1667-conforming test above 8,500 pounds GVWR), and bars registration until the vehicle passes or receives a certificate of waiver (49-542(D)). A.A.C. R18-2-1006 sets the test procedures and the Area A opacity cutpoints, and A.A.C. R18-2-1030(B) sets the visible emissions standard used for the Area B loaded opacity test.
Where the test happens and what it costs
- Where you register
- Arizona runs no carrier enrollment or reporting system for heavy diesel emissions. The test happens at an ADEQ emissions station in the Phoenix or Tucson area, or at a permitted fleet emissions inspection station for a fleet, and the result ties to the vehicle's registration renewal.
- What compliance takes
- The registration renewal notice from MVD says whether a vehicle needs a test that year. A vehicle may be tested at any Phoenix or Tucson station, but the tests differ by area. The inspection is due within the 90 days before the registration expiration date, and the program provides for fleet emissions inspection stations and for fleet operators to contract directly for testing.
- Inspection fee
- $23.75 (ADEQ's posted fee for the snap opacity test in the Phoenix area, the test a heavy diesel takes in Area A. The Tucson snap opacity fee is $20.45, and the loaded opacity test is $15.20 in Phoenix and $12.25 in Tucson. No 2027 figure is published. Payment is by cash, Arizona-bank check payable to ADEQ, or card.)
- Testing cadence
- Annual. 49-542 requires a diesel registering in Area A to pass an annual emissions test, and the Area B diesel table in R18-2-1006 lists heavy diesel testing as annual. The test is taken within the 90 days before the registration expires.
- Test methods
- Area A (metro Phoenix): diesel over 8,500 pounds GVWR takes the SAE J1667 (February 1996) snap-acceleration smoke opacity test, reported as percent opacity with the J1667 Appendix B ambient corrections. Area B (Tucson): a diesel over 26,000 pounds GVWR or with tandem axles takes a loaded opacity test on a chassis dynamometer, or lugged by its own brakes where no dynamometer is available, judged against the R18-2-1030(B) standard over 10 consecutive seconds. ADEQ's own test page says Tucson diesels over 26,000 pounds get the snap acceleration test; the rule text controls where the two differ. Every diesel also gets a tampering inspection.
- Registration holds
- Yes. A.R.S. 49-542(D): a vehicle shall not be registered until it has passed the emissions inspection and the tampering inspection or has been issued a certificate of waiver, and a waiver issues only once per vehicle after January 1, 1997. A waiver requires that the recommended repairs were done up to the statutory cost cap, $500 for a diesel over 26,000 pounds or with tandem axles in Area A and $300 in Area B.
Opacity cutpoints by engine model year
Opacity is the share of light the exhaust blocks. An older engine gets a looser number because the cutpoints were written around the technology of its build year, so a truck that passed last decade on a 40 percent limit is held to a tighter one once it is replaced.
Scroll sideways to see every column.
Area A cutpoints come from R18-2-1006, keyed to the engine model year on the emission control label. The ADEQ director may set a less stringent standard for an engine family that cannot meet the cutpoint in good repair, or that CARB has exempted. A truck that fails needs a low emissions tune-up before reinspection. The R18-2-1030(B) elevation bands apply to the Area B loaded tests; which band a given Tucson station uses was not stated in the sources read.
Who the program covers
The program is local. It reaches diesels registered in the two emissions areas, metro Phoenix and Tucson, plus vehicles registered elsewhere but driven to a job inside them. A truck registered in the rest of Arizona is outside it, and so is an apportioned fleet, which ADOT exempts from Arizona emission testing.
Metro Phoenix adds one more rule for the heaviest diesels that pay gross weight fees there: the truck must be at or past a set model year, or run an engine certified to the federal standards, to operate in the area at all.
Where the test happens, and what it costs
There is nothing to enroll in. Your registration renewal notice says whether the truck needs a test that year, and you take it at an ADEQ emissions station in the Phoenix or Tucson area within the window before registration expires. Fleets can use permitted fleet inspection stations instead.
ADEQ posts a flat fee for each test type, and the snap test costs a little more than the loaded test in both areas. Each posted amount carries its ADEQ source.
The opacity test and the cutpoints
In metro Phoenix a heavy diesel takes the SAE J1667 snap-acceleration test, reported as percent opacity, and the cutpoint depends on the engine model year printed on the emission control label. A missing or unreadable label means the stricter standard applies.
In Tucson the heaviest diesels take a loaded opacity test on a dynamometer, or lugged against their own brakes, judged against an elevation-based standard. ADEQ's own test page describes the Tucson heavy test differently, and where the two disagree the rule text controls.
What failing costs
Arizona enforces this program through the registration. A truck that has not passed, and holds no certificate of waiver, will not be registered. A failed truck needs a low emissions tune-up before it retests.
The waiver is narrow: it issues once per vehicle, only after the recommended repairs are done up to a statutory cost cap that is higher in Phoenix than in Tucson. No roadside smoke-testing program and no dollar penalty appear in the sources we read.
What this page does not cover
This program is registration-driven and local. It reaches a truck registered in metro Phoenix or Tucson, not a carrier based elsewhere in Arizona and not an apportioned (IRP) fleet, which ADOT exempts from Arizona emission testing. No dollar penalty for a missed heavy diesel test was found on the sources read and none is recorded: the consequence is that MVD will not renew the registration. The Area A 1988 model-year operating rule for diesels over 26,000 pounds is recorded under applies_to.
Where the inspection fits in the Arizona stack
The inspection deadline rides on the registration date, so it belongs on the same calendar as the credentials in start a trucking company in Arizona and the apportioned renewal in Arizona IRP registration. The rest of the state permit picture lives in Arizona trucking permits.