Role Of An Expert Witness in Montgomery County DUI Cases

In a Maryland DUI case, the use of expert witnesses can be an important factor for both the prosecution and the defense. Below, a Montgomery County DUI lawyer discusses the use of expert witnesses and the impact they can have on a case. For assistance with your case, call and schedule a consultation today.

How The Prosecution Uses Expert Witnesses

There’s going to be one expert witness in a DUI case that the prosecution is always going to call. In Maryland in the past couple of years, the States Attorney’s Office has be forced to qualify a police officer as an expert in order for them to testify as to the results of a horizontal gaze nystagmus test, which is one of the three standardized field sobriety test that officers will give to suspected DUI drivers.

This recent development has resulted in one of two things happening in different jurisdictions:

  1. One, the state will send a letter saying that we intend to qualify this officer as an expert pre-trial to your defense attorney.
  2. Other jurisdictions have decided they’re going to avoid the hassle of admitting or qualifying the officer as an expert and have stopped trying to admit the horizontal gaze nystagmus test.

Due to the fact that the case law states that the horizontal gaze nystagmus test is only admissible to show the presence of alcohol, rather than any kind of impairment by alcohol, the test has the same evidentiary value as the officer saying “I smelled alcohol or the individual admitted drinking alcohol.” As such, a lot of State’s Attorney’s Offices haven’t decided that that evidentiary benefit is worth the hassle of qualifying officers as expert.

What Other Types of Experts Might The Prosecution Call?

The other types of expert witnesses you’ll see, however, are a lot rarer, but they’re a lot more important to the state’s case, and those will almost always be medical witnesses. If an individual is hospitalized and can’t give a breath sample, then they will be asked to submit a hospital blood draw for purposes of determining alcohol impairment.

Unlike a breath test, there are no presumptions that are attributed to a blood test—meaning that if an individual submits to certified breath test conducted by a certified operator on a certified machine, then that numeric result will create certain presumptions in the court. There is no equivalency in the realm of a blood test. Anytime an individual submits to a blood test, the prosecutor is going to need to call in an expert to explain the result of that blood test to the court. They normally bring in the state’s chief medical officer , or one of his assistants. This witness is a qualified expert because they have given this type of testimony in lots of different cases all over Maryland. That is going to be the second most common expert that you see in DUI cases.

How Can a DUI Lawyer Refute These Claims?

There are a couple of ways for a Montgomery County DUI lawyer to refute the claims of a government expert. One way is to challenge the expert himself. You can say that this individual isn’t really an expert by challenging their qualifications prior to their testimony being admitted. You can question them on other literature material that may disagree with their expert opinion. You can use professional publications and other texts to challenge the expert, or you can bring in your own expert that has drawn a different set of conclusions from the same set of facts.

How The Defense Uses Experts

The defense attorney can call a number of different experts to help build a Dui defense in Montgomery County. They can include:

  • Accident reconstruction experts
  • Experts in the administration of field sobriety test in some circumstances.
  • Experts in breath test or blood test analysis.

How Important is An Attorney Who Knows Good Experts?

If the case is going to turn on a battle of experts, you want to have the best experts possible. You want to have the strongest possible defense. So hiring an attorney who really has experience handling expert witnesses and who has a pool of expert witnesses that they can call on that have been successful in other cases is going to be really important in your case.

Weight Experts Are Given At Trial

The judge or jury, whoever is hearing the case, is going to decide how much weight the testimony is given in the end. It’s going to depend on the quality of the expert, how well you can make your case. There’s no one-size-fits-all formula for that. It really is one of those human aspects of the practice of law. An experienced DUI attorney is someone who understands how to use these intangible factors in order to help their clients.