Do I Need Expert Witnesses for DUI Charges?

When do you need expert witnesses for DUI charges? In Hamrick v. State, the SC Supreme Court reversed a felony DUI conviction because the trial court allowed an officer to testify as an expert witness when the officer was not qualified as an expert witness.

Although 1) the Court did not qualify the officer as an expert witness and 2) the officer did not have the training and experience necessary to be qualified as an expert witness, the Court allowed him to testify as to accident reconstruction principles and the location of a construction worker when the defendant’s vehicle struck him – a critical issue in the case.

The Supreme Court found that it was error to allow the testimony by the officer, that it was not “harmless error,” and went on to find that it was also error for the trial court to not allow evidence from the defendant’s accident reconstruction expert.

Attorneys often think of expert witnesses as essential in the context of civil cases – medical malpractice, construction defects, or trucking accidents, for example. But what about criminal trials? Specifically, what about DUI trials?

When do I need expert witnesses for DUI charges, and when does the State need expert witnesses in a DUI trial?

When Does the State Need Expert Witnesses for DUI Charges?

If “scientific, technical, or other specialized knowledge” is required to explain an issue to jurors, then the witness must be qualified as an expert by the Court. Rule 702 of the SC Rules of Evidence says:

If scientific, technical, or other specialized knowledge will assist the trier of fact to understand the evidence or to determine a fact in issue, a witness qualified as an expert by knowledge, skill, experience, training, or education, may testify thereto in the form of an opinion or otherwise.

Expert testimony can be in the form of an opinion – a witness who has been qualified as an expert can give their opinion on what they think happened, based on their training, expertise, research, or tests that they have conducted.

A non-expert witness, also called a “lay witness,” cannot testify as to their opinion, answer hypothetical questions, or educate the jurors on matters that require “specialized knowledge.” According to Rule 701 of the SC Rules of Evidence:

If the witness is not testifying as an expert, the witness’ testimony in the form of opinions or inferences is limited to those opinions or inferences which (a) are rationally based on the perception of the witness, (b) are helpful to a clear understanding of the witness’ testimony or the determination of a fact in issue, and (c) do not require special knowledge, skill, experience or training.

Basically, a lay witness is only permitted to testify as to things they saw, heard, or otherwise personally experienced.

A Police Officer Cannot Give an “Expert” Opinion Unless They are Qualified as an Expert

In Hamrick, the state attempted to use the officer to testify as an expert in accident reconstruction despite the officer’s lack of expertise in the area. Over repeated objections, the trial judge allowed his testimony – calling what was clearly an attempt at expert testimony “lay testimony.”

To convict for felony DUI, it is not enough for the state to prove that a person was driving under the influence. It is also not enough for the State to prove that a person was driving under the influence and another person was injured or died.

The state must prove that the defendant committed an “act forbidden by law or neglect[ed] any duty imposed by law in the driving of the motor vehicle, which . . . proximately cause[d] great bodily injury . . . to another person.”

In this case, the State wanted to prove that Hamrick 1) was speeding; 2) failed to keep a proper lookout; and 3) that he struck the alleged victim, a road construction worker, outside of the lane of travel.

Instead of calling an accident reconstructionist (malpractice that would be the subject of a lawsuit if the prosecutor were instead a civil attorney), the State repeatedly attempted to qualify their chief investigator as an expert in accident reconstruction – the problem is that he was not an expert in accident reconstruction.

Despite not being present at the time of the accident and not personally witnessing what lane the defendant was traveling in, the officer gave his opinion on what happened, including the position of the vehicle and the alleged victim, as the judge called it “lay testimony.”

What should the prosecution have done? They should have contacted an accident reconstructionist and called them to testify at the trial.

Why didn’t they?

When Do I Need Expert Witnesses for DUI Charges?

Do you know who did call an accident reconstructionist for the trial? The defendant’s defense lawyer.

Except the trial judge, who allowed the State’s non-expert to give an expert opinion, also refused to allow the defense’s qualified accident reconstructionist to present a videotape of an experiment designed to determine whether it was possible for the defendant to have struck the alleged victim outside the lane of travel.

Finger on the scale much?

Without mentioning what appears to be a clear bias on the part of the trial court, the Supreme Court points out why the defense’s actual expert should have been allowed to present the results of his experiment:

We find the trial court conducted an erroneous analysis of the admissibility of the video. The proper analysis begins with the question of whether the evidence is relevant. See Rule 402, SCRE (“All relevant evidence is admissible . . . .”). Rule 401 provides evidence is relevant if it has “any tendency to make the existence of any fact that is of consequence to the determination of the action more probable or less probable than it would be without the evidence.” Rule 401, SCRE. The video of Poplin’s experiment was clearly relevant because the video tended to prove Hamrick could not have struck Garland in the construction zone as the State claimed he did.

Although the bad rulings from the trial court limited the effectiveness of the defense’s expert witness (and enabled the prosecutor to cheat and violate the rules to get a conviction), there is no doubt that an expert witness was necessary for the defense in this case and that they will be allowed to present their complete testimony on retrial.

What are some other examples of situations where you may need expert witnesses for DUI charges?

  • Accident reconstructionists are almost always needed in any felony DUI prosecution;
  • To challenge the validity of field sobriety tests administered on the roadside;
  • To challenge the validity of test results like the breathalyzer, blood tests, or urine tests;
  • To explain the effects of specific medications, food, drink, or other variables on a breathalyzer result;
  • To explain the effects of physical limitations on field sobriety tests; or
  • Any other situation that arises that requires “scientific, technical, or other specialized knowledge.”

Felony DUI Defense in Charleston, SC

Grant B. Smaldone is a SC DUI defense lawyer based in Charleston, SC, who accepts criminal defense cases including felony DUI charges.

If you have been charged with a crime in state or federal court in SC, call now at (843) 808-2100 or contact us online to talk to a Charleston, SC criminal defense attorney today.


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