Expert Witnesses in Virginia DUI Cases 

Most DUI cases do not use an expert witness for either side because Virginia law creates a presumption of impairment at anything higher than a 0.08 BAC. If a person just has alcohol in their system and the government has a chemical test, either blood or breath, to determine that number, the government does not need an expert to prove their case. Circumstances under which a person would need an expert include cases in which a person had no alcohol but rather drugs in their system. There is no presumptive impairment level of any drug in Virginia, so the government must have an expert come in and testify. Contact a skilled attorney for more information on experts

How DUI Lawyers Challenge Prosecution

Lawyers are not scientists, but lawyers who practice DUI law must possess a significant grasp of the science that can be involved in these kinds of cases. That training will guide an attorney in questions or themes of cross-examination to try to exploit some of the potential weaknesses in the science that can be involved in DUI cases. The other way is by having their own expert, somebody who can come in and testify that the government’s expert has faulty reasoning. An experienced attorney will know how to properly use an expert witness in a Virginia DUI case.

Who Experts Are

If it is a blood-related case, the person that conducted the blood test in the field of gas chromatography might be called upon as an expert witness in a Virginia DUI case. That person will describe the testing process and explain why it is or is not considered accurate. If there were drugs present, as opposed to alcohol, then there is no presumption of impairment and therefore the government must have an expert who can testify as to what that level of toxicity in the blood means in terms of a person’s ability to operate a motor vehicle safely.

Weight of Expert Witnesses

The weight of expert witnesses in Virginia DUI cases depends on how good the expert is and how good the lawyer is at extracting the expert’s testimony. It also depends on the court and on the government’s experts. When one expert says something different than another expert, the judge has to decide which side is right and which side is wrong. Judges are also lawyers and few judges have any scientific backgrounds, so it is up to lawyers to present the expert testimony in a coherent way that allows the court to see the rightness of their expert’s side and the wrongness of the government’s expert’s side.

Challenging Experts

Challenging the experts depends on what expert witnesses of the government the defense is trying to discredit or. If it is a toxicity case in which the court is concerned about the level of a certain drug in a person’s system, the government expert might say that the person would be impaired if they had a certain level of a certain drug in their system.

However, that might not be well-founded science and the defense might have an expert witness in a Virginia DUI case who claims something to the contrary. Also, the defense might have an expert come in to talk about the process of the blood test itself and whether or not the procedure used by the Virginia Department of Forensic Science was appropriate. Very often it is found that blood tests are not conducted the way that they are supposed to be conducted and that there are flaws in the science that is involved. Having an expert witness is critical to explain to a court why that is a flawed process.

What Happens at Trial with Experts

When the expert in a Virginia DUI case takes the stand, they will first have to be proposed as an expert to the court and subjected to questioning by both sides as to their viability as an expert. The witness’s history, training, and general expertise comes into play. At the conclusion of the questioning, the judge will make a ruling as to whether or not the court will accept that person as an expert witness and then the expert will be afforded certain facts about the case and asked to give an opinion as to what their expertise means in terms of the question they were called upon to answer.

Benefits of Expert Witnesses

The benefit of an expert witness is that they can speed up a case. Attorneys have several experts of all variations in their contact list who they can call upon at a moment’s notice to give an honest opinion about the facts of the case and whether or not their information or expertise would be useful in each case. For more on expert witnesses in Virginia DUI cases, call a professional attorney.