Court Rejects Defendant’s Expert Testimony in Recent Arizona DUI Case

Expert testimony is often necessary in Arizona DUI cases. Therefore, understanding the use and limits of expert testimony is essential. In a recent Arizona DUI case, an appellate court considered whether the trial court exceeded its authority in limiting expert testimony.

According to the court’s decision, the defendant was driving in Tucson, when his car crossed into the median, which was lined with palm trees. The defendant’s car crashed into a tree, and three passengers died, one of whom was pregnant. The defendant was also taken to the hospital, and a blood test showed that he had a blood-alcohol content (BAC) of .180. The defendant was charged with multiple counts of DUI, manslaughter, and negligent homicide.

At trial, the defendant argued that the roadway was defective, and that the roadway’s design caused the crash. The jury found him guilty, and he was sentenced to a total of 16.5 years in prison. On appeal, the defendant argued that he did not receive a fair trial, in part because the court excluded testimony from his expert witnesses. He argued that most of his expert’s testimony was improperly precluded.

On appeal, the court first noted that the expert was permitted to testify that the intersection was “unsafe” and presented a higher likelihood of severe injury due to the presence of the trees in the median. The court went on to explain that the expert was properly precluded from testifying about the city’s knowledge of the dangerousness of the intersection because the testimony was irrelevant and posed a danger of unfair prejudice.

The court also held that the defendant’s second expert witness, who was a former traffic engineer, was also properly prevented from testifying. The expert planned on testifying that the intersection was “abnormally complex” and that better maintenance and markings would have prevented the deaths. The court explained that the probative value of the testimony was outweighed by the danger of unfair prejudice and because the expert was not available for the trial. Moreover, the court found, the evidence repeated evidence already presented by the defendant’s other expert witness. Therefore, the court affirmed the jury’s verdict.

Expert Testimony

Expert testimony is generally governed by Arizona Rule of Evidence 702. Rule 702 states that an expert may testify in the form of an opinion or otherwise if:

(a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue;
(b) the testimony is based on sufficient facts or data;
(c) the testimony is the product of reliable principles and methods; and
(d) the expert has reliably applied the principles and methods to the facts of the case.

Trial court judges have the discretion to limit expert testimony if the testimony is unreliable or irrelevant. However, the jury generally determines the credibility and weight to afford expert testimony.

Contact a Mesa DUI Defense Attorney

Arizona has very harsh drunk driving laws and severe penalties for those who are found guilty of an Arizona DUI. If you have been arrested for DUI, talk to an experienced DUI attorney as soon as possible. James Novak of the Law Office of James E. Novak has over 13 years of experience representing those charged with Arizona DUI offenses. He represents individuals throughout Tempe and the surrounding areas, including, Mesa, Gilbert, Chandler, Phoenix, Scottsdale, and East Valley. Contact the Law Office of James E. Novak at 480-413-1499 to schedule a free consultation today.