Question: Why would you need an expert witness in a DUI case in Maryland?
Answer: Well, a drunk driving charge is, of course, very serious and it has long-term consequences across the board—whether it be work or license or professional licensing and all that kind of stuff. The proof of a DRE case is actually quite scientific, and can be quite scientific, depending on how deep, one gets into it and what the nature of your defense in your case is. So, for example, in a breath test case, there are defense experts that can come to court and you have to retain these experts and they will talk about the breath machine and exactly how they work and exactly how the machine can be affected, either by a police officer saying or doing something wrong, or by a defendant not so much saying but doing something wrong.
So, for example, if a police officer tells you to take a deep breath and then hold that breath and then blow in the machine as hard as you can, by taking that deep breath and holding it you’re allowing more oxygen to interact in your esophagus and in your lungs, more specifically, and yet the alcohol content in your lungs is exchanging and the BAC volume that you are going to exhale, that number is going to be increased dramatically, versus if you simply took in a breath and exhaled it. Now, the police know perfectly well, the trained ones, that if you tell somebody to take a deep breath and hold it for as long as they can and then blow it in the machine, they know what they’re doing. Why else would they ask you to hold your breath? It’s not necessary to hold your breath. You simply breathe in, you breathe out and that would ostensibly be an effective and an accurate test. But instead, they ask you to hold your breath and when they do that, they are doing that because they want you to blow a falsely high number.
So you can bring in, one can retain the services of an expert to talk about the machine and to talk about how behavior like that can provide a falsely high number. There are also other things, there are medical conditions that one can go into, like partition ratios in different human beings and experts can come in and talk about how different people have different partition ratios, and how the breath machines are generically built on one specific partition ratio, and if a human being has a higher or lower ratio, their number is going to be off, either higher or lower, based on the machines. And an expert would have to come in and talk about that—an expert on the machine and, quite possibly, depending on how deep somebody wanted to go, perhaps a medical doctor to talk about partition ratios.
Conversely, in talking about a blood test, they have elaborate machines that they use at the crime lab in Pikesville, Maryland that test one’s blood and that would potentially require an expert to come in to explain how the machine works and what problems that machine can have and if the maintenance on the machine was not done accurately. But, more specifically than that, if you’re going to bring an expert in, he can talk about the proper procedures to operate these machines and perhaps it was not done by the crime lab and the results are skewed in one form or another. So, if you really want to get deep into the defense of these cases, then you would have to bring in an expert to do that, you would have to pay for such an expert to come in. But they can be an extremely effective way to help defend cases.
Aside from having those types of experts, one can bring in medical experts of one form or another that can speak to different things, different characteristics that a person may have that might affect the machine. So, you can bring in experts from the medical field, you could bring in experts, if it’s a breath machine, there are experts in the country that can come talk about the breath machine and where their shortcomings are and how it affected you in this case. And there are experts that can talk about the gas machines that the crime lab uses to evaluate blood numbers. There are many, many different types of scientific experts, because if you want to get into the nitty gritty of a DUI case, these are the types of experts that you may need to bring in, and they can be helpful.