If you’ve recently been charged with DUI in Surprise, Arizona, one of the most crucial elements of your case may hinge on the accuracy and admissibility of your breathalyzer test results. At AZ DUI Pros, we have one core mission: challenging breathalyzer results to protect your rights and fight for your future.
Our legal team has worked with hundreds of clients facing DUI allegations where the primary evidence was a questionable BAC reading. When law enforcement and machines determine your fate, you deserve a firm that knows exactly how to challenge that evidence. That’s where AZ DUI Pros comes in — and we’re just one phone call away at (602) 922-3755.
Understanding Breathalyzer Results in Arizona DUI Cases
Arizona takes DUI enforcement seriously. Under ARS § 28-1381, you can be charged with a DUI even if your driving wasn’t impaired — as long as your blood alcohol concentration (BAC) is 0.08% or higher.
But these machines are not foolproof. That’s why challenging breathalyzer results is a vital strategy in DUI defense, especially in Surprise, where roadside tests are increasingly common during traffic stops. Here are just a few reasons your breathalyzer result might not be as solid as the prosecution claims:
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Improper calibration or maintenance
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Operator error
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Mouth alcohol contamination
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Physiological variances (like acid reflux or ketosis)
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Rising BAC after you were already driving
Common Problems with Breathalyzer Accuracy
Many believe breathalyzer devices are scientifically precise. But there’s growing evidence that these machines are not only fallible but can be grossly inaccurate under certain conditions. The Intoxilyzer 8000, used throughout Arizona, has a long list of issues that defense attorneys use in challenging breathalyzer results.
Top Factors That Lead to Inaccurate Readings:
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Calibration Issues: Devices must be regularly maintained and recalibrated under Arizona Department of Public Safety standards. Failure to do so can void the result.
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Environmental Factors: Radio interference, temperature, and humidity can skew readings.
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Operator Error: If the officer didn’t follow proper protocols, the test may be inadmissible.
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Medical Conditions: GERD, diabetes, and other health issues can create “mouth alcohol,” skewing results.
These flaws form the foundation of successful defense strategies focused on challenging breathalyzer results in Surprise DUI cases.
Arizona DUI Law: ARS 28-1381
ARS § 28-1381 is the statute that governs DUI charges in Arizona. It establishes two types of DUI:
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Impairment DUI: Driving while impaired “to the slightest degree,” regardless of BAC.
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Per Se DUI: Driving with a BAC of 0.08% or more within two hours of operating a vehicle.
For those accused under this statute in Surprise, challenging breathalyzer results can be the difference between a conviction and a dismissal. If the BAC reading is proven unreliable, the prosecution may have no other evidence of impairment.
Breathalyzer Testing and Constitutional Rights
Understanding Your Rights During a DUI Stop
When you’re pulled over for suspected DUI in Surprise, Arizona, your constitutional rights don’t disappear at the roadside. One of the most overlooked but critical areas in challenging breathalyzer results is whether those results were obtained in a way that respects the Fourth and Fifth Amendments of the U.S. Constitution.
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Fourth Amendment: Protects against unreasonable searches and seizures
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Fifth Amendment: Guards against self-incrimination
A breathalyzer test can implicate both, depending on how it was administered and whether the officer followed proper legal procedures.
Was the Breathalyzer a Legal Search?
Many DUI arrests hinge on the legality of the initial stop and the ensuing test. In Arizona, law enforcement needs probable cause before they can demand a breath test. If an officer initiates a stop without a valid reason — such as a vague suspicion or profiling — it could form the foundation for challenging breathalyzer results based on illegal search.
Additionally, consent plays a major role. While Arizona operates under an “implied consent” law, you still have the right to refuse a breathalyzer — although that may lead to license suspension. But if an officer forces the test without consent or a warrant, that could constitute a rights violation.
Miranda Rights and Self-Incrimination
Some Surprise DUI cases also involve statements made during or after the test. If officers question you without advising you of your Miranda rights, anything you say could be suppressed — and that includes admissions about drinking, which prosecutors often use alongside BAC results.
If your defense team can show that your rights were violated at any point, it may be possible to exclude the breathalyzer results altogether. That’s why challenging breathalyzer results isn’t just a scientific battle — it’s also a constitutional one.
Why This Matters for Your Case
Even a high BAC doesn’t guarantee a conviction if it was obtained illegally. At AZ DUI Pros, our attorneys regularly file motions to suppress evidence when constitutional rights are violated. These motions can result in:
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Entire DUI cases being dismissed
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Reduced charges
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Weakened prosecution leverage in plea negotiations
If you believe your rights were violated during your arrest in Surprise, challenging breathalyzer results may be your strongest path to justice.
Hypothetical Scenario 1 – The Faulty Machine
Tom, a 45-year-old schoolteacher in Surprise, Arizona, was pulled over for a broken tail light. The officer claimed he smelled alcohol and administered a breathalyzer test. The result? 0.10% BAC — just over the legal limit. Tom was arrested and charged under ARS § 28-1381(A)(2).
However, Tom insisted he had only one drink three hours before driving. His attorney at AZ DUI Pros immediately started challenging breathalyzer results in the case. During discovery, it was revealed that the Intoxilyzer 8000 used had not been properly calibrated in over six weeks, violating the Arizona Department of Health Services’ administrative code.
The attorney filed a motion to suppress the breath test, arguing the machine’s readings were unreliable and should be excluded. The court agreed, and without a valid BAC reading, the prosecution couldn’t meet its burden of proof under ARS § 28-1381. The case was dismissed.
In this scenario, challenging breathalyzer results was a decisive factor in Tom avoiding a DUI conviction.
Hypothetical Scenario 2 – The Rising BAC Defense
Lena, a 28-year-old graphic designer, was driving home through Surprise after a company dinner. She was pulled over for making a wide right turn. Officers conducted a field sobriety test and later used a breathalyzer, which read 0.09%. She was charged under ARS § 28-1381(A)(2).
Lena told officers she had two glasses of wine but had stopped drinking 30 minutes prior. Her legal team at AZ DUI Pros employed the rising BAC defense — one of the most powerful tools in challenging breathalyzer results. The argument is simple: alcohol takes time to be absorbed into the bloodstream. Lena’s BAC could have been under the legal limit while she was driving but rose to 0.09% by the time she took the breathalyzer.
The defense presented expert testimony and Lena’s meal timeline, showing her BAC was likely below 0.08% when she was actually behind the wheel. This created enough reasonable doubt for the case to be dropped.
Once again, challenging breathalyzer results was critical in preserving Lena’s clean record.
Field Sobriety Tests vs. Breathalyzer Results: What Holds Up in Court?
Two Very Different Types of Evidence
When someone is arrested for DUI in Surprise, the state often relies on two main types of evidence: Field Sobriety Tests (FSTs) and breathalyzer results. But these tests are not created equal in the eyes of the law — and understanding their differences is crucial to challenging breathalyzer results effectively.
FSTs include:
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Walk and Turn
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One-Leg Stand
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Horizontal Gaze Nystagmus (HGN)
These are subjective assessments based on the officer’s interpretation of your physical performance. Breathalyzers, on the other hand, produce numerical BAC data — which gives them a scientific edge. Or so it seems.
Field Sobriety Test Problems
FSTs are inherently flawed for a few reasons:
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Physical condition: Injuries, fatigue, or medical conditions can impair performance
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Environment: Uneven ground, poor lighting, or bad weather affects results
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Officer bias: These are subjective judgments that often favor the prosecution
Defense attorneys often use poor FST performance to create reasonable doubt — or to highlight inconsistencies when challenging breathalyzer results.
When Results Don’t Match
Here’s where it gets interesting: Sometimes a person performs well on FSTs but poorly on the breathalyzer, or vice versa. These inconsistencies are ripe for legal challenge.
Imagine a Surprise driver aces the walk-and-turn and one-leg stand but blows a 0.09% on the breathalyzer. This contradiction can be presented in court to argue that the breathalyzer result is unreliable, especially when supported by the driver’s appearance and behavior at the time of arrest.
In other words, a clean FST record can undermine a breath test, and that’s a powerful tool when challenging breathalyzer results in Surprise courts.
Strategic Defense: Use One to Discredit the Other
The key to building a strong DUI defense is understanding how to leverage one type of evidence to discredit the other. At AZ DUI Pros, we frequently use FST performance to challenge the validity of BAC readings. Conversely, if FSTs were poorly administered, we highlight procedural errors to cast doubt on the entire arrest.
So whether it’s a subjective field test or a supposedly scientific breathalyzer, both have weaknesses — and when used together strategically, they offer multiple angles for challenging breathalyzer results in your defense.
Frequently Asked Questions
Q: What should I do immediately after failing a breathalyzer in Surprise, AZ?
A: Contact AZ DUI Pros at (602) 922-3755 immediately. Early legal intervention is essential in challenging breathalyzer results.Q: Are breathalyzer results always admissible in court?
A: No. If the device wasn’t calibrated, the officer was untrained, or protocols weren’t followed, the results may be thrown out.Q: Can medical issues affect breathalyzer accuracy?
A: Yes. Conditions like GERD, asthma, or diabetes can skew results — a key angle in challenging breathalyzer results.Q: How long do DUI cases take in Surprise Municipal Court?
A: It depends, but typically 3–6 months. The more aggressive your legal team is in challenging breathalyzer results, the sooner it may be resolved.Q: Will a DUI show on my background check if charges are dropped?
A: It can, unless the record is sealed or expunged. That’s why a strong defense from AZ DUI Pros is essential.
Conclusion: Why AZ DUI Pros Is Your Best Ally
At AZ DUI Pros, we believe no one should be convicted based on flawed science or faulty machines. If you’ve been arrested in Surprise or the greater Phoenix area, and you’re serious about challenging breathalyzer results, we’re the team to call.
We understand the law. We understand the science. Most importantly, we understand how to win.
📞 Call us now at (602) 922-3755 for a confidential consultation. Don’t leave your future to chance.
Relevant Arizona Statutes
ARS § 28-1381 – DUI
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Driving or being in actual physical control of a vehicle while under the influence of intoxicating liquor, any drug, a vapor releasing substance, or any combination thereof.
ARS § 28-1381(A)(2) – Per Se DUI
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Having a BAC of 0.08 or more within two hours of driving.
ARS § 28-1323 – Breath Testing Protocols
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Mandates that breath testing devices be properly calibrated and that operators be certified.
These statutes form the legal backdrop for challenging breathalyzer results and can be crucial in your defense.
