When you get a DUI in Arizona, it can seem like the cards are stacked against you—and in many ways, they are. But, there is one critical aspect of Arizona’s DUI laws that protects suspects no matter what. This is the prosecution’s burden of proof.

Understanding the Burden of Proof in an Arizona DUI Case

Driving under the influence (DUI) in Arizona is a criminal offense. In fact, it is a felony offense in many cases. Since DUI is a criminal offense, the burden of proof rests with the prosecution.

What is the “burden of proof”? Simply put, it means that the prosecution needs to prove that you were driving under the influence in order to secure a conviction. If the prosecution cannot prove that you are guilty, you do not need to prove your innocence. In this scenario, the prosecution failed to meet its burden, and this means you are entitled to walk free.

Arizona’s “Beyond a Reasonable Doubt” Standard for DUI Cases

The prosecution must prove your guilt “beyond a reasonable doubt to meet its burden of proof.” The Supreme Court of Arizona explained what this means in the case of State v. Portillo, 18 Ariz. 592, 596 (1995):

“Proof beyond a reasonable doubt is proof that leaves you firmly convinced of the defendant’s guilt. There are very few things in this world that we know with absolute certainty, and in criminal cases the law does not require proof that overcomes every doubt. If, based on your consideration of the evidence, you are firmly convinced that the defendant is guilty of the crime charged, you must find him/her guilty. If, on the other hand, you think there is a real possibility that he/she is not guilty, you must give him/her the benefit of the doubt and find him/her not guilty.”

As you can see, Arizona law requires jurors to be “firmly convinced” of a defendant’s guilt. If jurors believe there is a “real possibility” that a defendant is not guilty, they must find in the defendant’s favor.

The requirement to prove a criminal defendant’s guilt “beyond a reasonable doubt” is rooted in the constitutional principle of due process. If a court allows a defendant to be convicted on proof that falls below this constitutional standard, then the defendant’s conviction should not stand. However, it is up to the defendant to establish that his or her constitutional rights have been violated; in this case, the burden rests with the defendant.

How Can the Prosecution Prove Guilt “Beyond a Reasonable Doubt” in a DUI Case?

While it might seem difficult to convince a panel of jurors of a defendant’s guilt “beyond a reasonable doubt,” prosecutors routinely secure convictions for DUI and other crimes. The government’s attorneys have access to all of the evidence obtained by the police, and, if they decide to take a case to trial, it is generally because they believe they have what they need to secure a conviction.

In some DUI cases, a single piece of evidence (or just a few pieces of evidence) may be enough. For example, if prosecutors present a breathalyzer reading of 0.08% or above, if the arresting officer testifies that the defendant was driving before his or her arrest, and if the defendant fails to challenge the officer’s account or the reliability of his or her blood alcohol concentration (BAC), then the jury may be left with little choice but to find the defendant guilty. This is based on Arizona’s “strict liability” DUI law, which states that a person is guilty, “[i]f the person has an alcohol concentration of 0.08 or more within two hours of driving or being in actual physical control of the vehicle.”

Prosecutors will need other evidence when they are not able to rely on a defendant’s BAC, but they may be able to obtain this evidence from various sources. The arresting officer’s testimony, field sobriety test results, evidence of open containers, the defendant’s own statements, and various other forms of evidence can all be used to present a compelling case for guilt. Even if one piece of evidence isn’t enough to convince the jury members on its own, the prosecution’s entire body of evidence may leave the jury “firmly convinced” that the defendant is guilty of DUI.

How Can DUI Defendants Prevent Prosecutors From Meeting Their Burden of Proof?

If you are facing a DUI charge in Arizona, what can you do (if anything) to prevent prosecutors from meeting their burden of proof?

There are several ways to fight a DUI charge in the Arizona courts. Since prosecutors have the burden of proof, they must be able to prove each element of the defendant’s charge “beyond a reasonable doubt.” This means that casting doubt on any single element of a DUI under Arizona law can be enough to avoid a conviction. With this in mind, some of the ways DUI defendants may be able to fight their charges include:

  • Challenging the prosecution’s evidence that the defendant was “under the influence”
  • Challenging the reliability or accuracy of the defendant’s BAC reading
  • Challenging the prosecution’s evidence that the defendant was in “actual physical control”
  • Challenging the prosecution’s evidence that the defendant was driving a “vehicle”
  • Challenging the admissibility of the prosecution’s evidence in court (i.e., due to an unconstitutional traffic stop or arrest)

Additionally, while defendants don’t need to prove their innocence to avoid a conviction, proving innocence can be a strong defense strategy in appropriate cases. If, working with your DUI lawyer, you can clearly establish that you had not been drinking before your arrest, then presenting evidence of your innocence could be more than enough to establish a “real possibility” that you are not guilty in the minds of the jurors.

Request a Free Consultation with a Tempe DUI Lawyer at The Weingart Firm

If you need to know more about defending against a DUI charge in Arizona, we encourage you to contact us for a free consultation. To speak with a Tempe DUI lawyer at The Weingart Firm in confidence as soon as possible, call 480-405-7922 or tell us how we can reach you online now.