The BAC limit in Arizona is not a single number. For most drivers 21 and older, the per se blood alcohol concentration limit is 0.08%, but the state also sets a 0.04% limit for commercial drivers, a zero-tolerance rule for anyone under 21, and elevated offense tiers at 0.15% (Extreme DUI) and 0.20% (Super Extreme DUI). A driver can also be convicted of DUI with a BAC well below 0.08% under Arizona’s “impaired to the slightest degree” standard.
The Standard 0.08% Limit
For drivers 21 and older in a non-commercial vehicle, the per se BAC limit is 0.08%. If a chemical test shows your blood alcohol concentration at or above that level within two hours of driving, you are presumed to be under the influence under A.R.S. § 28-1381. The prosecution does not need additional evidence of impairment to bring the charge.1Arizona Legislature. Arizona Revised Statutes 28-1381 – Driving or Actual Physical Control While Under the Influence
That’s the number most drivers know. It isn’t the whole story.
You Can Be Convicted Below 0.08%
Arizona law makes it illegal to drive while impaired by alcohol or drugs “to the slightest degree.” The provision sits in the same statute, at A.R.S. § 28-1381(A)(1), and carries the same penalties as a per se violation.1Arizona Legislature. Arizona Revised Statutes 28-1381 – Driving or Actual Physical Control While Under the Influence
That means a BAC reading of 0.05% or 0.06% can support a conviction if the prosecution shows any measurable effect on your driving ability. Evidence in these cases comes largely from officer observations: weaving within a lane, delayed reactions, slurred speech, or poor performance on field sobriety tests. Officers often issue two citations after a DUI stop, one for impairment to the slightest degree and another for exceeding the 0.08% per se limit. If the BAC result gets excluded at trial, the impairment charge can still stand.
Staying under 0.08% is not, by itself, a legal shield.
Extreme DUI at 0.15% and Super Extreme DUI at 0.20%
Arizona raises the stakes at two higher BAC thresholds, both charged under a separate statute, A.R.S. § 28-1382.2Arizona Legislature. Arizona Revised Statutes 28-1382 – Driving or Actual Physical Control While Under the Extreme Influence of Intoxicating Liquor
- Extreme DUI applies when your BAC is between 0.15% and 0.199%. A first offense carries a minimum of 30 consecutive days in jail (reducible to 9 days with a 12-month ignition interlock) and at least $2,500 in fines and statutory assessments.
- Super Extreme DUI applies when your BAC is 0.20% or higher. A first offense carries a minimum of 45 consecutive days in jail (reducible to 14 days with a 12-month interlock), at least $2,750 in fines and assessments, and an 18-month ignition interlock requirement.3Arizona Legislature. Arizona Revised Statutes 28-3319 – Action After License Suspension, Revocation or Denial
Court surcharges push the actual out-of-pocket cost at each tier above the statutory minimums.
Commercial Drivers: 0.04%
If you hold a commercial driver’s license, the per se BAC limit drops to 0.04% while you are operating a commercial vehicle. That is exactly half the standard threshold, and it is written directly into A.R.S. § 28-1381(A)(4).1Arizona Legislature. Arizona Revised Statutes 28-1381 – Driving or Actual Physical Control While Under the Influence
The CDL consequences are separate from the criminal penalties and apply even when the DUI happened in your personal vehicle. Under A.R.S. § 28-3312, a first DUI conviction triggers at least a one-year disqualification from commercial driving. The disqualification is at least three years if you were transporting placarded hazardous materials. A second DUI conviction brings lifetime disqualification. All three tiers are mandatory.4Arizona Legislature. Arizona Revised Statutes 28-3312 – Mandatory Disqualification of Commercial Driver Licenses
Under 21: Zero Tolerance
Arizona enforces a zero-tolerance standard for drivers under the legal drinking age. Under A.R.S. § 4-244, it is illegal for a person under 21 to drive or be in physical control of a motor vehicle with any amount of alcohol in their body. No specific BAC reading is required. Any detectable amount triggers the violation.5Arizona Legislature. Arizona Revised Statutes 4-244 – Unlawful Acts
A violation is a Class 1 misdemeanor carrying up to six months in jail and up to $2,500 in fines, though there is no mandatory minimum jail time for a first offense. Drivers under 18 face a mandatory two-year license suspension on conviction.6Arizona Legislature. Arizona Revised Statutes 28-3320 – Suspension on Conviction of Certain Offenses by Person Under Eighteen An underage driver who reaches 0.08% or shows signs of impairment can also be charged under the standard DUI statute and face the same penalties as an adult.
Drugs and Marijuana
BAC limits only govern alcohol. Arizona runs a parallel rule for drugs. Under A.R.S. § 28-1381(A)(3), driving with any drug listed in A.R.S. § 13-3401, or its metabolite, in your body is a DUI offense. Covered substances include cocaine, methamphetamine, heroin, and prescription medications you take without a valid prescription. If a licensed practitioner prescribed the drug to you, you have a statutory defense against this specific charge.1Arizona Legislature. Arizona Revised Statutes 28-1381 – Driving or Actual Physical Control While Under the Influence
Marijuana is the major exception. After Arizona voters passed Proposition 207, the Smart and Safe Arizona Act, the metabolite-only rule no longer applies to marijuana. A driver cannot be convicted under the drug-metabolite provision solely for having marijuana or its metabolites in their system. The prosecution must prove actual impairment to the slightest degree.7Morrison Institute for Public Policy. Understanding Proposition 207, the Smart and Safe Arizona Act This matters because marijuana metabolites can remain detectable for weeks after use, long after any impairment has worn off.
Refusing a Breath or Blood Test
Staying under the limit is not the same as avoiding the test. By driving on Arizona roads, you have given implied consent to a chemical test of your blood, breath, or urine if an officer has reasonable grounds to suspect impaired driving. Refusing carries its own penalties under A.R.S. § 28-1321.8Arizona Legislature. Arizona Revised Statutes 28-1321 – Implied Consent; Tests; Refusal to Submit to Test
A first refusal results in an automatic 12-month license suspension. A second refusal within 84 months (seven years) extends the suspension to two years. These are administrative suspensions imposed by the Motor Vehicle Division and operate on a track separate from any criminal DUI case, so you can lose your license for refusing even if you are never charged with or convicted of DUI. After a first refusal, you may apply for a special ignition interlock restricted license once you complete alcohol or drug screening ordered by the department; that option is not available after a second or subsequent refusal within the 84-month window.