Role of Expert Witnesses in Manassas DUI Cases

If accused of driving under the influence in Manassas, Virginia, an expert witness may be used at trial. Below, a Manassas DUI lawyer discusses the different types of witnesses that may be used in a DUI case and how much weight these experts are given. To learn more, call and schedule a consultation today.

Roles of Expert Witnesses in Prosecution of DUI Cases

The prosecution would not generally rely on experts for witnesses in alcohol-based DUI cases. This is because they have a per se level written into the statute indicating 0.08 or higher is considered intoxicated. They don’t need any experts to testify about what an alcohol level relates to in a person’s impairment. They will, however, have to rely on expert witnesses to address the issue of impairment in drug related cases. In many cases where the Commonwealth alleges the presence of drugs in the person’s system, the Commonwealth is also alleging the impairment of that person. They need to have an expert explain to the court what a certain level of certain drugs really means when in a person’s blood system.

How a Manassas DUI Lawyer Refutes or Challenges the Opposing Expert’s Claims

If they have an expert, we’re going to need one too. Our expert will look at the analysis performed by the government’s expert and see if the procedures or theories used by the government expert might be flawed. Then our expert will bring that to life and perform their own analysis of the situation and evidence to determine if the government’s claims are accurate.

Experts the Defense May Call in Manassas DUI Cases

It depends on the case type and what we’re trying to establish. Generally speaking, we may potentially call a toxicology expert to address the possible shortcomings of the breath testing process. We might call a gas chromatography expert to challenge the blood testing process or the blood testing analysis. We might call a toxicology expert to address the issue of impairment in blood cases that involve drugs that don’t have presumptive levels under the statute. There are lots of rules for experts in these kinds of cases because they are based in science. When science meets the law, experts are almost always required.

Why Is It Important to Have an Attorney Who Knows Good Experts?

It’s important to have an attorney who knows good experts. It’s likely that the attorney has worked with those experts before and understands what they’re bringing to the table in terms of experience and credentials. The attorney will know how to work well with the expert to extract the right kind of information while testifying. I personally have experts I have been using that I’ve known for well over a decade. I find that the familiarity with them really helps me prepare the case for trial and in trying the case itself.

Weight Experts Are Given in Trial

It depends on the expert and what kind of credentials they have. It also depends on what kind of testing they’ve done in the past. In cases where an expert testifies for the government and an expert testifies for the defense, I don’t think that the government’s expert necessarily is valued more than the defense’s expert if the defense’s expert has the right experience and credentials and also appears to have analyzed the evidence impartially.