Role of Expert Witnesses in Virginia DUI Cases

If accused of driving under the influence and brought to trial, an expert witness may be used in your case. Below, a Virginia DUI lawyer discusses the impact an expert witness can have on your case, the types of experts the defense can use, and the weight that an expert witness will carry at trial. For more information on how a witness can have an impact on your case, call and schedule a consultation with an attorney today.

How Experts Are Used in Virginia DUI Cases

In the majority of DUI drug cases, expert witnesses will be called upon by the government in order to lay the proper foundation for the admissibility of the blood test. While these experts are important to the prosecution’s case, they can often be challenged by a Virginia DUI lawyer regarding the blood’s chain of custody, the methods that were used to collect the blood, whether proper procedure was followed, and whether there was any opportunity for contamination.

Experts Called By The Defense

The defense can also call forensic experts who can refute the accuracy of the blood test, explain why a breathalyzer machine may have been malfunctioning, or who can testify that the blood alcohol that has shown in the test could not possibly have been correct because the accused did not consume enough alcohol to generate that result.

Importance of Experts To The Defense

Good experts can make the difference in a DUI case between being convicted and being acquitted. Just like other kinds of witnesses and other kinds of evidence, there are some expert witnesses who do very well testifying at trial and there are others who don’t do as well under cross examination. Having an attorney who knows good expert witnesses and knows which ones to use and which ones to avoid can be invaluable in your case.

How Much Weight Are Experts Given In a DUI Trial?

At trial, the experts are called as witnesses who are going to give opinions about certain things. Most witnesses can only testify as to facts that they know, or in other words, things that they have seen or heard or have received through the five senses in some way. They cannot give opinions or interpretations, however, an expert witness, once it is shown that they are an expert in a particular field, can offer opinions about certain things.

For example, a forensic scientist who is an expert on the breathalyzer machines could give testimony that the breathalyzer machine was not operated properly by a police or that the machine was malfunctioning or some other procedure was not followed. This kind of testimony is given significant weight by judges in certain kinds of cases. This kind of expert testimony can often be the difference between being convicted and being acquitted.