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August 8, 2023

Most Common Types of DUI Defenses

Driving under the influence, more commonly known as drunk driving or driving while intoxicated, is a heavily punishable criminal offense in Tucson, Arizona. The state considers DUI a “violent crime” and results in harsh punishments, even for first offenders. 

DUI: The Legal Definition in Arizona

ARS § 28-1381 defines a DUI offense as being in physical control of a vehicle while under the influence of intoxicating liquor, drugs, vapor-releasing substance, or a combination of these substances that can impair a driver at even the slightest degree. More specifically, people are considered intoxicated if they have a blood-alcohol content (BAC) level of 0.08% or higher. If they drive a vehicle within two hours of exceeding the minimum BAC, they can be subject to a DUI charge, lose their driver’s license, and serve jail time.

Not everything is black and white, however, and every DUI case has different circumstances. If you or someone you love gets a drunk-driving charge, you’ll need solid DUI defense strategies and an experienced DUI defense attorney to defend your rights. 

Common DUI Defenses 

Here are examples of DUI defense options that you can use depending on the circumstances surrounding your case. Note that DUI defenses aren’t a remedy to dismiss your case instantly. Rather, they are a good starting point to build your case, so having an experienced DUI defense lawyer on your side is vital. 

Let’s get started.

  1. Unreliable Breath Alcohol Test Results

Police officers use breathalyzers to determine if a driver has exceeded the acceptable intoxication threshold. These devices analyze the amount of alcohol vapor in the lungs and determine a person’s BAC level. However, the value that breathalyzers provide is an indirect measurement of a person’s blood alcohol level. Moreover, they can give false positives due to several factors:

  • You sipped an alcoholic drink just before taking the test.
  • You just had a spicy meal, ripe fruit, or an energy drink.
  • You have certain medical conditions like acid reflux, hyperacidity, GERD, heartburn, etc.
  • The device wasn’t calibrated correctly. 

If any of these scenarios apply, you can add this argument to your DUI defense strategies. 

  1. Unreliable Blood Test Results

Like with the breathalyzer results, you can challenge the integrity of your blood tests if you have reason to believe your sample may have been contaminated, tampered with, or improperly handled, such as it wasn’t stored properly or it took hours before your blood sample was tested in a lab. BAC findings are often evidence in drunk-driving cases, so contesting its accuracy and reliability is also one of the most common DUI defenses.

  1. Improper Field Sobriety Testing (FST)

Most people behave exactly as you would expect of a drunk person. Hence, police officers conduct FST to verify intoxication. The three standardized FSTs are the one-leg stand, walk-and-turn, and horizontal gaze nystagmus test. 

The first thing you should know is you’re not required to do an FST in Arizona. You have the right to refuse, which you should do if circumstances aren’t in your favor:

  • You’re wearing high heels.
  • You are overweight.
  • You have a disability that impairs your ability to walk straight.
  • You are of retirement age.

If you agree to perform FSTs, your performance can be used against you. Suppose you complied with the tests and didn’t do so well. You can counter with these DUI defenses:

  • You were asked to perform non-standardized tests (i.e., reciting the alphabet, Rhomberg-Modified balancing tests, finger-to-nose exercises) that aren’t approved by the National Highway Traffic Safety Administration (NHTSA).
  • You weren’t driving over the speed limit or swerving (there was no reason for the officer to pull you over, save for a haunch).

The second counter argument brings us to another of the most common DUI defenses you can use, not because it is a loophole but because many officers violate this rule.

  1. Illegal Stop of Your Vehicle

Traffic law states that officers can only pull over a vehicle if they have a reasonable and articulable basis of cause. This means they can only stop a moving car on the road and check for the possibility of a DUI if:

  • The driver broke a traffic law.
  • The driver broke non-traffic laws.


Police officers only need minor violations like broken tail lights to pull over a vehicle legally. Only then can they investigate you for possible intoxication. But if you didn’t break any laws and they have no reasonable cause for suspicion, your DUI defense attorney can build a case for dismissal. 

This is one of the textbook DUI defenses attorneys can use: prove that the officers performed an unlawful stop because they had no basis to stop your vehicle. If the court agrees, any evidence the police obtains after pulling you over – an over 0.08% breathalyzer result or failed FSTs – will become inadmissible under the exclusionary rule. The prosecutor will have no choice but to drop the charges against you. 

  1. No Probable Cause for Arrest

The Fourth Amendment of the US Constitution protects everybody from unreasonable searches and seizures. The state bears the burden of proving they have legally obtained evidence that a crime has been committed. 


This applies to getting pulled over for suspected drunk driving. The burden of proof lies on the police officers, and they cannot pull you over simply because they have a hunch that you’re intoxicated. Watch out for unreasonable causes for stopping your car; they are some of the best DUI defense strategies you can use to dismiss your DUI charge:

  • You were spotted leaving a bar before getting into your car.
  • You were driving late at night.
  1. No Actual Driving or Physical Control of the Vehicle

Arizona’s law explicitly defines DUI as driving and having physical control of a vehicle while under the influence of alcohol, thereby becoming a threat to others. So, if you weren’t driving or in control of a vehicle at the time of arrest, the state doesn’t have a case against you. 

For example, if you sat inside your car with the engine running to turn on the air conditioning, fully intending to wait until the effects of the alcohol wore off, you can make a case before the jury that you weren’t driving and aren’t guilty of DUI. This is one of the most common DUI defense options your defense attorney can use. However, you may need solid evidence, like interior dash cam footage, to strengthen your case. 

Here are more examples of circumstances that can benefit from this argument:

  • You had already pulled over and parked your car before the police found you.
  • The police didn’t actually see you driving.
  • You had a drink after parking your car or getting into a road accident.
  • You were drunk, but it wasn’t you behind the wheel.

It’s difficult to disprove “actual physical control of a vehicle” in court. The prosecution will use the following to prove that you were:

  • You were seated in the driver’s seat.
  • The keys were in the ignition.
  • Both your hands were on the steering wheel.
  • The car was in Drive (if the vehicle is automatic). 

Choose a Seasoned Tucson DUI Defense Attorney To Represent You

Knowing your DUI defense options is just half of what you need. You must also have a reliable Tucson dui defense attorney who knows can chip away at the prosecution’s case against you. 

Atty. Efthymios Katsarelis of Katsarelis Law, PLLC, is a top-rated criminal defense attorney in Tucson who can help you build a strong case against a DUI charge. He has years of experience in litigation for various DUI offenses, like drunk driving, first-time offenders, felony hit and run, and out-of-state DUI. If you are charged with any of these offenses, contact us right away. 

You may call (520) 510-0439, email us at [email protected], or fill out our Contact Form to get in touch.  

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Don’t know where to start yet? It is necessary to find yourself a highly experienced criminal defense lawyer who will help you navigate through better. Speaking with an experienced assault attorney will explain to you the available options and assist you in getting the best possible outcome.

For any charges that need an attorney to help, reach us on 520-510-0439, 177 North Church Avenue, Suite 600, or send us a mail at [email protected]. Our crime attorneys in Arizona and Tucson are dedicated to helping clients achieve the best possible outcomes in their cases. We do this by negotiating with the government, preparing for trial, and litigating motions to suppress evidence. Assault is a serious crime that could result in jail time and other penalties. Let us help you avoid these consequences as much as possible.

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