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Expert Witnesses in Atlanta DUI Cases

If you get arrested for drunk driving – officially called driving under the influence, or DUI, in Georgia – then you will get a first-hand look at our criminal justice system. This includes everything from the initial criminal charge, to evidence gathering and trial preparation, to negotiations with the prosecution, to the trial, itself.

Among the other things that you will see is how witnesses are used by the court. This comes up both during trial preparation, and in the actual trial. Witnesses are often the backbone of a criminal case, and the field of DUI cases is no exception to this rule.

Both the prosecution and your criminal defense attorney will use witnesses in most DUI cases. The prosecution will call upon the police officer who made the arrest, as well as the person who conducted a blood or urine test, if one was administered. Either side may bring in people who were present at the arrest, or expert witnesses, who can challenge evidence or make statements about what they think of the case. Throughout, your criminal defense attorney will challenge whoever the prosecutor calls on, and try to poke holes in the case against you. The prosecution will try to do the same to whoever your defense attorney takes to the stand.

This might seem fairly simple and straightforward. That is because we have only covered the basics, so far. Now, we will go over the complexities, when it comes to witnesses in a DUI case.

Witnesses in a DUI Case

You can categorize all witnesses in a DUI case into two groups: Regular witnesses, and expert witnesses. Each group has its advantages and its disadvantages, and each group can effectively do some things, in a properly conducted trial, but not others.

Here are the details on each group.

Regular Witnesses

Regular witnesses are the people who have a direct knowledge of the specific case that is being heard by the court. In a DUI case, regular witnesses can include you, as the driver, as well as any passengers in the car, the policeman who made the traffic stop, any other people in the area who saw the event unfold, and anyone who directly handled evidence that was gathered during the investigation. When a regular witness takes the stand in a DUI trial, they can answer questions about what happened in this particular case.

During a DUI case, the police officer is often the most important witness, because what they did during the traffic stop can make or break the case for the prosecution. Not only were they the ones who initiated the traffic stop and the arrest, but they are also the person who is the most involved the criminal proceedings, outside of the driver being arrested. This means that they see much more of the law enforcement's investigation than other witnesses involved in the case.

Additionally, the actions of the police officer are crucial to the development of the case. If the police officer did not perform a sobriety test correctly, or decided to pull the driver over without a valid reason, then some evidence, or even the entire case, can be thrown out because the police officer acted improperly.

For both of these reasons, the police officer is a crucial witness to a DUI case, and is why they are almost always present at a DUI trial. It also makes their cross-examination – when the criminal defense attorney gets to challenge what they have said and done – one of the key points in the trial.

Some of these reasons also seem to suggest that you, as the driver, would also be an important witness, as well. Testifying as a witness has the potential to help your case, but it also has the potential to severely undermine it, as well. This is because, while testifying allows you to get on the stand and say exactly what you saw happen, how you were feeling, what you did, and why, it also gives the prosecutor the opportunity to cross-examine you. They will try to take everything that you have said, in your defense, and make it sound like you are even more guilty of DUI. Additionally, if you have a prior criminal history, taking the stand allows them to ask questions about it, so the jury can hear that you have a criminal background. Testifying is often a very unpleasant experience.

Luckily, taking the stand in your own defense in a trial is an option that you have. You should discuss this option with your defense attorney, who will have a good idea of whether it will help in your defense, or whether it might hurt your case.

Expert Witnesses

The other category of witnesses are expert witnesses. Expert witnesses were not there at the time of the traffic stop, or at any time during the investigation, but have a great deal of knowledge of the things that are involved in the case. Therefore, expert witnesses can talk about how things work, in general, and then give their opinion on how it affects your particular case. For example, your defense attorney can use an expert witness who understands exactly how the specific breath testing machine used by the police works, and have them explain how the machine could have given inaccurate results in your case. Or, they can use a retired police officer to explain to the jury how the arresting officer improperly administered a sobriety test.

While expert witnesses can be incredibly helpful to win a DUI case, they are also very expensive to use, as they all charge a fee to take the stand in your case. Whether you need an expert witness in order to win your case is something that you should discuss with your attorney as soon as the decision to take the case to trial has been made.


While witnesses will always fall into these two categories, the types of things that they will say on the stand varies, depending on the type of case before the court. Having an experienced DUI attorney on your side is crucial, as they will know the best ways to interact with witnesses, in the DUI context. Not only do I have more than 20 years defending DUI cases, I started my career as a prosecutor, so I also know what the prosecution is thinking, which is often invaluable. Call me at (404) 816-4440, if you have been arrested and charged with DUI in Georgia.

Call Us 24 Hours a Day

We have a line that will be answered any time, day or night. If you have been arrested for DUI and are facing arraignment at 8:00am tomorrow, or if you are anywhere else in the judicial process, contact the Office of Richard Lawson as soon as possible. Call Us 24 Hours a Day: (404) 800-5810


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