PA Superior Court: DUI Defendant May Call Expert Witness to Attack Validity of Field Sobriety Tests

Philadelphia Criminal Defense Lawyer Zak Goldstein

Philadelphia Criminal Defense Lawyer Zak Goldstein

The Pennsylvania Superior Court has decided the case of Commonwealth v. Taylor. In Taylor, the Superior Court reversed the defendant’s conviction for DUI because the trial court improperly prohibited the defendant’s expert witness from testifying that field sobriety tests have not been scientifically validated for use in detecting impairment due to drugs. This is an important decision for defendants who are facing DUI charges and who may not have submitted to a blood test because it may allow the defendant to use expert testimony to attack the validity of field sobriety tests. 

Commonwealth v. Taylor

The defendant was driving her car in York County, Pennsylvania with her 18-month-old child secured in the back seat.. She was driving twenty miles above the speed limit, and  when a traffic light in front of her turned red, the defendant abruptly braked and nearly rear-ended a stopped vehicle in front of her. A few seconds after the light turned green, the defendant rapidly accelerated her car over a nearby curb and crashed into a utility pole located about 100 feet from the road.

A motorist who saw the accident pulled over next to the defendant’s car and offered to help her. The defendant got out of her car and told the motorist that she was not injured. Thankfully, her child was also unharmed. While speaking with the motorist, the defendant attempted to shut her car door, but the motorist stopped it from shutting because it could have hit the child’s outstretched arm.

A local police officer arrived at the scene of the accident a few minutes later. He observed the defendant having blood shot eyes and slurred speech, but he did not smell alcohol on her. Per the officer, the defendant also appeared to be confused and very tired. The officer then had the defendant perform two standard field sobriety tests. He had her walk in a straight line and and then do a test involving walking and turning 180 degrees. According to the officer, the defendant performed poorly on the tests. She allegedly had trouble  balancing herself and following directions. The defendant’s body swayed during the tests, and she used her arms to keep steady. She also started the tests before being told to do so.

The officer arrested the defendant on suspicion of DUI and Endangering the Welfare of a Child (“EWOC”). While in custody, she admitted to taking Adderall and Xanax, but she could not provide the amounts taken or how long before the accident she had taken the medications. She denied having any injuries or medical conditions that could have affected her ability to operate a motor vehicle. At trial, the Commonwealth did not allege that the defendant was impaired by alcohol. Further, the Commonwealth did not introduce the results of any blood testing into evidence. Instead, the Commonwealth relied primarily on the arresting officer’s testimony regarding the defendant’s car accident and how she performed on the field sobriety tests. The officer testified at length regarding his expertise in administering those tests. Other than describing the scene of the accident, almost all of the officer’s testimony was focused on how poorly the defendant performed on the tests. He further testified that the defendant’s performance indicated impairment due to drug use.

The defense attributed the defendant’s performance to a possible head injury from the accident. Additionally, the defendant attempted to rebut the officer’s testimony with the opinion of its own expert witness, a medical toxicologist and physician. The doctor planned to testify that there was no scientific basis to rely on field sobriety tests to detect drug impairment because they have only been validated to reveal intoxication from alcohol. The trial court qualified the doctor as an expert in toxicology and on the scientific basis for field sobriety tests.

The doctor testified that he reviewed the defendant’s medical history and confirmed that she had been prescribed Xanax and Adderall. He also testified that after using the medication for 30 days, the medications should have little to no side effects. The defendant had been prescribed the medication for over 30 days prior to the accident, but there was no evidence regarding what dosages she took. However, when the doctor attempted to testify about field sobriety tests, the Commonwealth objected and the court sustained the objection. As such, the doctor could not testify about the utility of field sobriety’s tests in detecting drug impairment. At the conclusion of the trial, the jury found the defendant guilty of DUI and EWOC. The defendant then filed post-sentence motions which were denied. The defendant then filed a timely appeal.

What is Expert Testimony?

Rule 702 of the Pennsylvania Rules of Evidence governs expert testimony. Expert testimony is not relevant in every case. In other words, you cannot call an expert to claim that a witness is lying. It is only admissible when an expert has an opinion on a subject which requires knowledge, information, or skill beyond what is possessed by the ordinary juror. In criminal cases, expert witnesses are most often used in cases that involve some form of medicine or science. They are common in DUI cases and many motor vehicle cases.

In determining whether to qualify someone as an expert, courts are supposed to employ a liberal standard when determining if a witness qualifies as an expert in a particular field of study. The witness does not need to possess all of the knowledge in a given field, but the witness must possess more knowledge than is otherwise within the ordinary range of training, knowledge, intelligence or experience. Further, a witness does not need formal education to qualify as an expert, although it certainly helps. This case focused on whether a witness can testify as an expert witness without having practical, hands-on experience in the field. In this case, the trial court prohibited the doctor from testifying that the tests had not been validated for detecting drug usage because the doctor was not a police officer and had never performed the tests on someone himself.

The Superior Court’s Decision

The Superior Court held that it was reversible error for the trial court to preclude the doctor’s testimony concerning field sobriety tests. As a preliminary matter, the Superior Court held that the doctor was qualified as an expert in this particular field and that the Commonwealth did not dispute any of these qualifications. Additionally, the Superior Court found that the  testimony would have gone to the heart of the issues in the defendant’s trial.

The Commonwealth was trying to prove that the defendant was impaired due to drug use, and prosecutors did not have any blood test results. They sought to prove intoxication by using the testimony of the officer and his observations of the defendant. They specifically sought to base a potential conviction on his observations of the defendant when she performed the field sobriety tests. If the doctor’s  testimony had been admitted, it could have rebutted the officer’s conclusion that the defendant was impaired by drugs. As a result of the judge’s preclusion of  the doctor’s testimony, the officer’s opinion on the defendant’s drug impairment went unchallenged. Therefore, this error in excluding the expert testimony resulted in significant prejudice to the defendant, and she will receive a new trial.

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Philadelphia Criminal Defense Lawyers Demetra Mehta and Zak Goldstein

Philadelphia Criminal Defense Lawyers Demetra Mehta and Zak Goldstein

If you are facing criminal charges or are under investigation by the police, we can help. We have successfully defended thousands of clients against criminal charges in courts throughout Pennsylvania and New Jersey. We have won cases involving charges such as Conspiracy, DUI, Aggravated Assault, Rape, Possession with the Intent to Deliver, and Homicide. Our award-winning Philadelphia criminal defense lawyers offer a free criminal defense strategy session to any potential client. Call 267-225-2545 to speak with an experienced and understanding defense attorney today.