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How an Alcohol Expert Witness Can Help in DUI Cases

Drivers that get behind the wheel while intoxicated may run the risk of being pulled over by law enforcement officers. When charged and convicted of these crimes, they have driving under the influence offenses on their record. For many states, the more of these on a person’s record, the worse the penalties become as they progress.

However, it is possible to have a positive outcome in a case with no conviction through an experienced lawyer and an expert witness who may explain various aspects that lead the judge to believe that the individual was not actually intoxicated while he or she drove on the road. This may include medications, alcohol still in the mouth from before the trip, liquor still digesting and similar issues.

There are many aspects to a DUI case that need to be clarified, explained and disputed. Of these, field sobriety tests or breathalyzer machines need to be examined thoroughly. These devices could be calibrated incorrectly, handled and maintained inappropriately and the officers using them may not have the proper training to ensure readings are accurate. This means that there are some persons convicted of a DUI that were not over the national legal blood alcohol
content level of .08. It may take an expert witness to assist in determining this fact. If medication is the reason, the professional should be able to discover and explain this situation as well.

The Expert Witness

When someone is hired as an expert witness in a case, he or she has the experience in the field necessary to explain certain aspects, facts or evidence of the issue. This person has extensive understanding and knowledge of a subject, and this usually includes education, special skills, years of training and practical applications of the concept. For a DUI expert witness, this individual is able to understand what the law enforcement officers go through, what devices are used and what is needed to complete the forensic toxicology with blood, urine and breath samples. This person is able to testify for the defending party in court and explain away various elements.

There are several fields of study that an expert witness may have trained under, and this would affect the case in how this aspect is utilized. An example of this would be a professional in the medical field knowing that certain samples have only so much of a shelf life before they degrade and the results may be skewed. Scientific procedures may explain why certain breathalyzers have different analysis than others and how calibration may affect the sample taken in the field. Medical backgrounds may also assist with medication and health complications with DUI cases. These processes are invaluable at proving the defendant was not intoxicated while driving.

Other Expert Fields Related to the DUI

There are a number of other professionals and experts used to assist with DUI cases. The expert witness may be from various different fields of study. If he or she has a working knowledge of law enforcement, then he or she knows the procedures that will occur for the person charged with the crime. He or she will also understand what the individual goes through and what the officers attempt to accomplish. With another field of forensic toxicology, the professional may have a greater grasp of the science and procedures behind the case in regards to the alcohol levels. The blood alcohol content may be analyzed through certain tests, but this expert may explain to the judge or jury how the results may be inaccurate based on how the test was administered, what tools were used and similar concerns.

Experts that understand field sobriety tests may detail to the court that administration is often completed incorrectly or with equipment known to be unreliable to determine true BAC levels. Some health conditions could cause up to 25 percent error in results. It may also be argued that road conditions and weather may have affected the driving of the individual arrested. If there was a traffic incident involved with the DUI arrest, the professional may be needed to reconstruct the event to the judge or jury are able to understand the nature of the problem and what truly occurred.


Coupling the details of the case together with the testimony of the expert witness, it is possible to deliberate with all the information regarding the incident. Hiring one of these professionals for the case often increases the chances of a successful resolution to the case.

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Disclaimer: While every effort has been made to ensure the accuracy of this publication, it is not intended to provide legal advice as individual situations will differ and should be discussed with an expert and/or lawyer.

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