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If you have been pulled over in Tucson or anywhere else in Arizona and are wondering how the state decides whether to charge you with a DUI, the answer comes down to a few specific measurements.
Arizona is known for having some of the strictest DUI laws in the country, and understanding how those numbers work can help you understand exactly what you are facing.
At Mulembo Law PLLC, we are proudly serving Tucson and all of Arizona, and we regularly help clients who are confused about how their charges were calculated in the first place.
Here is a breakdown of the measurements Arizona relies on.
Blood Alcohol Concentration (BAC)
The most common measurement in a DUI case is Blood Alcohol Concentration, or BAC.
This is the percentage of alcohol in a person’s bloodstream, and Arizona law breaks DUI charges into three tiers based on this number:
- Standard DUI: A BAC of 0.08% or higher
- Extreme DUI: A BAC between 0.15% and 0.199%
- Super Extreme DUI: A BAC of 0.20% or higher
Each tier carries its own mandatory minimum penalties, and the jump from one tier to the next can mean a significant difference in jail time, fines, and how long an ignition interlock device is required.
A Super Extreme DUI conviction, for example, can bring a mandatory minimum of 45 days in jail on a first offense, compared to just one day for a standard DUI. Even a small difference in the BAC reading, sometimes just a hundredth of a percent, can push a case into a harsher category.
BAC is typically measured through a breath test, a blood test, or occasionally a urine test, and Arizona law requires the measurement to be taken within two hours of driving.
“Impaired to the Slightest Degree” Without a BAC Number
Arizona does not require a specific BAC number to charge someone with DUI. Under A.R.S. § 28-1381, a driver can be charged if they are impaired “to the slightest degree” by alcohol, drugs, or a combination of substances, even if their BAC comes back under 0.08%.
This means officers can rely on field sobriety tests, driving behavior, and general observations to build a case, which is one of the reasons DUI charges in Arizona can be more aggressive than in other states.
This standard also applies to impairment from legal prescription medications.
If you want to see how this plays out in real cases, our blog covers the challenges of defending DUI cases involving prescription medication in more detail.
Commercial Drivers and Minors
Arizona uses different, stricter measurements for certain drivers:
- Commercial drivers can be charged with a DUI at a BAC of just 0.04%.
- Drivers under 21 fall under Arizona’s zero tolerance law, meaning any detectable amount of alcohol in their system can result in charges, regardless of impairment.
Drug-Related DUIs
Arizona does not rely on a simple numeric threshold for drug related DUIs the way it does with alcohol.
Instead, the state can charge a driver if any amount of an illegal drug, or its metabolite, is found in their system while operating a vehicle.
This applies even to substances that may have been in a person’s system from prior use and are not currently causing impairment, which makes drug DUI cases especially complex and worth fighting with the right legal strategy.
Why These Measurements Matter for Your Defense
Because Arizona’s DUI penalties escalate so quickly based on precise measurements, the accuracy and legality of how that measurement was obtained becomes critical to your defense.
Breath testing equipment must be properly calibrated and maintained, blood draws must follow strict procedures, and officers must have valid legal grounds for the stop in the first place.
Any misstep in this process can open the door to challenging the charge.
If you are facing a DUI anywhere in Tucson or the surrounding areas, it is worth having an experienced attorney review exactly how your BAC was measured and whether the process followed Arizona law.
Learn more about how our firm approaches these cases on our DUI Defense page, part of our broader Criminal Defense practice.
Talk to a Tucson DUI Attorney Today
DUI charges move fast, and the measurements used against you deserve a closer look. At Mulembo Law PLLC, we are proud to serve clients throughout Tucson and all of Arizona with personalized, aggressive representation.
Call us today at (520) 462-5110 or schedule a consultation online to discuss your case and find out what your options are.
