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Expert Witness Testimony in DC DUI Cases

Evidence is vital in DUI cases. Besides photographs and test results, another form of evidence that can be valuable is expert witness testimony. Expert witnesses are individuals who are experts in specific areas of knowledge, and use that knowledge to explain certain concepts on behalf of the prosecution and the defense. Expert witness testimony in DC DUI cases can help validate the defense’s argument and/or could also focus calling into question the prosecution’s case. Speak with an experienced DUI attorney that could help you retain the services of a reliable expert witness.

Process of Verifying an Expert Witness

At trial, the government calls an expert and qualifies them in a subprocess known as voir dire. The prosecution must show that the expert has the expertise, the technical knowledge, and the experience to testify and give an opinion. Once the expert is qualified, they can give their opinion; but that is on both the prosecutor and the defense side.

The judge also instructs the jury about how seriously to take expert witness testimony. The law is that an expert can testify about matters based on their experience and knowledge to give an opinion. Jurors or judges can either credit or discredit expert witness testimony in DC DUI cases. It is up to the fact finder, the jury or the judge, to give the weight of an expert’s opinion the importance they feel it deserves.

Requirements for Expert Witnesses

For someone to be an expert witness in the District of Columbia, there is a standard based on the Daubert case that says a witness qualified as an expert by knowledge, skill, experience, training, or education can testify by giving an opinion if the expert’s scientific, technical, or other specialties can help a judge or a jury understand the evidence.

Their testimony must be based on sufficient facts and reliable principles and methods. The expert has, in a reliable way, applied those methods and principles to the facts of the case. That is a change in the rules. The standard used to be under Frye, but this is the new standard that many courts use now including the District of Columbia local courts when verifying expert witness testimony in DC DUI cases

Role of an Expert Witness in the Prosecution’s Case

Prosecutors sometimes use different types of experts. They use a police officer as an expert in the application or administration of standardized field sobriety tests particularly the Horizontal Gaze Nystagmus (HGN) test. Sometimes, the prosecutors use an expert to talk about blood or breath alcohol levels if the issue is more complicated. For example, they use blood testing or urine testing as opposed to simply the breath test.

The experts called by the prosecution in DUI court are the police officer to talk about the administration of a standardized field sobriety test such as the HGN test and a toxicologist when there is an allegation of drugs being in someone’s system while they were driving. When there is an issue of testing, for example, the prosecutors try to establish that while a person’s blood alcohol level or breath alcohol level might have been lower when they were testing, it might have been higher using a regression analysis.

How Does a DUI Lawyer Challenge the Claims of the Government’s Experts?

A DUI lawyer can challenge the claims of the government’s experts in two ways. One is by cross-examining the government’s expert to show that the information they are relying on is not reliable, that the expert is not qualified to make the analysis, or they are biased because they are being paid money for their opinion. The defense attorney can call their own expert in the defense case to refute a government expert’s testimony.

Value of an Expert Witness in the Defense of a DUI

There are a couple of ways the defense can use expert witness testimony in DC DUI cases. One is to consult with to prepare for cross-examination of a government’s expert witness. The other is to call a defense expert in the defense case. It depends on the strategy of the defense because in some situations, there is not much government evidence. The lawyer may just want to use the consultation with a defense expert to get ready to cross-examine and not put on a defense expert. In other situations, the defense lawyer may want to put on their own expert and that decision can be made during the trial.

Typically, the expert a defense might call is an expert who can testify about breath testing procedures or blood and urine testing procedures when there is an issue in the case. Sometimes, the defense can call an expert about the standardized field sobriety tests and how those were administered.

Benefits of Working With a DC DUI Attorney That Knows Reputable Experts

The benefit of working with a qualified DUI lawyer is that they will have experience utilizing expert witness testimony in DC DUI cases. An attorney may have relationships with reputable experts in the case.

There is no benefit to the defense or the prosecution calling experts that are not reputable. They do not have any credibility and it is easy to poke holes in that type of testimony. It beneficial to work with an attorney who knows experts that are well-regarded, because it quickly becomes quite clear when an expert is not highly regarded. If an individual has been charged with a DUI offense they should speak with a lawyer that could help them retain the services of an expert witness that could help.

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